Re: [PATCH] kvm-pr: manage illegal instructions

[Thomas Huth]

On 18.05.2016 12:53, Thomas Huth wrote:
> On 18.05.2016 12:18, Thomas Huth wrote:
>> On 17.05.2016 19:49, Laurent Vivier wrote:
>>>
>>>
>>> On 17/05/2016 10:37, Alexander Graf wrote:
 On 05/17/2016 10:35 AM, Laurent Vivier wrote:
>
> On 12/05/2016 16:23, Laurent Vivier wrote:
>>
>> On 12/05/2016 11:27, Alexander Graf wrote:
>>> On 05/12/2016 11:10 AM, Laurent Vivier wrote:
 On 11/05/2016 13:49, Alexander Graf wrote:
> On 05/11/2016 01:14 PM, Laurent Vivier wrote:
>> On 11/05/2016 12:35, Alexander Graf wrote:
>>> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
 While writing some instruction tests for kvm-unit-tests for
 powerpc,
 I've found that illegal instructions are not managed correctly
 with
 kvm-pr,
 while it is fine with kvm-hv.

 When an illegal instruction (like ".long 0") is processed by
 kvm-pr,
 the kernel logs are filled with:

  Couldn't emulate instruction 0x (op 0 xop 0)
  kvmppc_handle_exit_pr: emulation at 700 failed ()

 While the exception handler receives an interrupt for each
 instruction
 executed after the illegal instruction.

 Signed-off-by: Laurent Vivier 
 ---
  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)

 diff --git a/arch/powerpc/kvm/book3s_emulate.c
 b/arch/powerpc/kvm/book3s_emulate.c
 index 2afdb9c..4ee969d 100644
 --- a/arch/powerpc/kvm/book3s_emulate.c
 +++ b/arch/powerpc/kvm/book3s_emulate.c
 @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
 *run,
 struct kvm_vcpu *vcpu,
switch (get_op(inst)) {
  case 0:
 -emulated = EMULATE_FAIL;
  if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
  (inst == swab32(inst_sc))) {
  /*
 @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
 *run,
 struct kvm_vcpu *vcpu,
  kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
  kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
  emulated = EMULATE_DONE;
 +} else {
 +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>>> But isn't that exactly what the semantic of EMULATE_FAIL is?
>>> Fixing it
>>> up in book3s_emulate.c is definitely the wrong spot.
>>>
>>> So what is the problem you're trying to solve? Is the SRR0 at the
>>> wrong
>>> spot or are the log messages the problem?
>> No, the problem is the host kernel logs are filled by the message
>> and
>> the execution hangs. And the host becomes unresponsiveness, even
>> after
>> the end of the tests.
>>
>> Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR
>> host,
>> and check the kernel logs (dmesg), then try to ssh to the host...
> Ok, so the log messages are the problem. Please fix the message
> output
> then - or remove it altogether. Or if you like, create a module
> parameter that allows you to emit them.
>
> I personally think the best solution would be to just convert the
> message into a trace point.
>
> While at it, please see whether the guest can trigger similar host
> log
> output excess in other code paths.
 The problem is not really with the log messages: they are
 consequence of
 the bug I try to fix.

 What happens is once kvm_pr decodes an invalid instruction all the
 valid
 following instructions trigger a Program exception to the guest
 (but are
 executed correctly). It has no real consequence on big machine like
 POWER8, except that the guest become very slow and the log files of
 the
 host are filled with messages (and qemu uses 100% of the CPU). On a
 smaller machine like a  PowerMac G5, the machine becomes simply
 unusable.
>>> It's probably more related to your verbosity level of kernel messages.
>>> If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
>>> the messages printed to serial which is what's slowing you down.
>>>
>>> The other problem sounds pretty severe, but the only thing your patch
>>> does any different from the current code flow would be the patch below.
>>> Or did I miss anything?
>>>

Re: [PATCH] kvm-pr: manage illegal instructions

[Thomas Huth]

On 18.05.2016 12:53, Thomas Huth wrote:
> On 18.05.2016 12:18, Thomas Huth wrote:
>> On 17.05.2016 19:49, Laurent Vivier wrote:
>>>
>>>
>>> On 17/05/2016 10:37, Alexander Graf wrote:
 On 05/17/2016 10:35 AM, Laurent Vivier wrote:
>
> On 12/05/2016 16:23, Laurent Vivier wrote:
>>
>> On 12/05/2016 11:27, Alexander Graf wrote:
>>> On 05/12/2016 11:10 AM, Laurent Vivier wrote:
 On 11/05/2016 13:49, Alexander Graf wrote:
> On 05/11/2016 01:14 PM, Laurent Vivier wrote:
>> On 11/05/2016 12:35, Alexander Graf wrote:
>>> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
 While writing some instruction tests for kvm-unit-tests for
 powerpc,
 I've found that illegal instructions are not managed correctly
 with
 kvm-pr,
 while it is fine with kvm-hv.

 When an illegal instruction (like ".long 0") is processed by
 kvm-pr,
 the kernel logs are filled with:

  Couldn't emulate instruction 0x (op 0 xop 0)
  kvmppc_handle_exit_pr: emulation at 700 failed ()

 While the exception handler receives an interrupt for each
 instruction
 executed after the illegal instruction.

 Signed-off-by: Laurent Vivier 
 ---
  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)

 diff --git a/arch/powerpc/kvm/book3s_emulate.c
 b/arch/powerpc/kvm/book3s_emulate.c
 index 2afdb9c..4ee969d 100644
 --- a/arch/powerpc/kvm/book3s_emulate.c
 +++ b/arch/powerpc/kvm/book3s_emulate.c
 @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
 *run,
 struct kvm_vcpu *vcpu,
switch (get_op(inst)) {
  case 0:
 -emulated = EMULATE_FAIL;
  if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
  (inst == swab32(inst_sc))) {
  /*
 @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
 *run,
 struct kvm_vcpu *vcpu,
  kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
  kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
  emulated = EMULATE_DONE;
 +} else {
 +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>>> But isn't that exactly what the semantic of EMULATE_FAIL is?
>>> Fixing it
>>> up in book3s_emulate.c is definitely the wrong spot.
>>>
>>> So what is the problem you're trying to solve? Is the SRR0 at the
>>> wrong
>>> spot or are the log messages the problem?
>> No, the problem is the host kernel logs are filled by the message
>> and
>> the execution hangs. And the host becomes unresponsiveness, even
>> after
>> the end of the tests.
>>
>> Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR
>> host,
>> and check the kernel logs (dmesg), then try to ssh to the host...
> Ok, so the log messages are the problem. Please fix the message
> output
> then - or remove it altogether. Or if you like, create a module
> parameter that allows you to emit them.
>
> I personally think the best solution would be to just convert the
> message into a trace point.
>
> While at it, please see whether the guest can trigger similar host
> log
> output excess in other code paths.
 The problem is not really with the log messages: they are
 consequence of
 the bug I try to fix.

 What happens is once kvm_pr decodes an invalid instruction all the
 valid
 following instructions trigger a Program exception to the guest
 (but are
 executed correctly). It has no real consequence on big machine like
 POWER8, except that the guest become very slow and the log files of
 the
 host are filled with messages (and qemu uses 100% of the CPU). On a
 smaller machine like a  PowerMac G5, the machine becomes simply
 unusable.
>>> It's probably more related to your verbosity level of kernel messages.
>>> If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
>>> the messages printed to serial which is what's slowing you down.
>>>
>>> The other problem sounds pretty severe, but the only thing your patch
>>> does any different from the current code flow would be the patch below.
>>> Or did I miss anything?
>>>
>>> diff --git 

Re: [PATCH] kvm-pr: manage illegal instructions

[Thomas Huth]

On 18.05.2016 12:18, Thomas Huth wrote:
> On 17.05.2016 19:49, Laurent Vivier wrote:
>>
>>
>> On 17/05/2016 10:37, Alexander Graf wrote:
>>> On 05/17/2016 10:35 AM, Laurent Vivier wrote:

 On 12/05/2016 16:23, Laurent Vivier wrote:
>
> On 12/05/2016 11:27, Alexander Graf wrote:
>> On 05/12/2016 11:10 AM, Laurent Vivier wrote:
>>> On 11/05/2016 13:49, Alexander Graf wrote:
 On 05/11/2016 01:14 PM, Laurent Vivier wrote:
> On 11/05/2016 12:35, Alexander Graf wrote:
>> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
>>> While writing some instruction tests for kvm-unit-tests for
>>> powerpc,
>>> I've found that illegal instructions are not managed correctly
>>> with
>>> kvm-pr,
>>> while it is fine with kvm-hv.
>>>
>>> When an illegal instruction (like ".long 0") is processed by
>>> kvm-pr,
>>> the kernel logs are filled with:
>>>
>>>  Couldn't emulate instruction 0x (op 0 xop 0)
>>>  kvmppc_handle_exit_pr: emulation at 700 failed ()
>>>
>>> While the exception handler receives an interrupt for each
>>> instruction
>>> executed after the illegal instruction.
>>>
>>> Signed-off-by: Laurent Vivier 
>>> ---
>>>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/powerpc/kvm/book3s_emulate.c
>>> b/arch/powerpc/kvm/book3s_emulate.c
>>> index 2afdb9c..4ee969d 100644
>>> --- a/arch/powerpc/kvm/book3s_emulate.c
>>> +++ b/arch/powerpc/kvm/book3s_emulate.c
>>> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
>>> *run,
>>> struct kvm_vcpu *vcpu,
>>>switch (get_op(inst)) {
>>>  case 0:
>>> -emulated = EMULATE_FAIL;
>>>  if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>>>  (inst == swab32(inst_sc))) {
>>>  /*
>>> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
>>> *run,
>>> struct kvm_vcpu *vcpu,
>>>  kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>>>  kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>>>  emulated = EMULATE_DONE;
>>> +} else {
>>> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>> But isn't that exactly what the semantic of EMULATE_FAIL is?
>> Fixing it
>> up in book3s_emulate.c is definitely the wrong spot.
>>
>> So what is the problem you're trying to solve? Is the SRR0 at the
>> wrong
>> spot or are the log messages the problem?
> No, the problem is the host kernel logs are filled by the message
> and
> the execution hangs. And the host becomes unresponsiveness, even
> after
> the end of the tests.
>
> Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR
> host,
> and check the kernel logs (dmesg), then try to ssh to the host...
 Ok, so the log messages are the problem. Please fix the message
 output
 then - or remove it altogether. Or if you like, create a module
 parameter that allows you to emit them.

 I personally think the best solution would be to just convert the
 message into a trace point.

 While at it, please see whether the guest can trigger similar host
 log
 output excess in other code paths.
>>> The problem is not really with the log messages: they are
>>> consequence of
>>> the bug I try to fix.
>>>
>>> What happens is once kvm_pr decodes an invalid instruction all the
>>> valid
>>> following instructions trigger a Program exception to the guest
>>> (but are
>>> executed correctly). It has no real consequence on big machine like
>>> POWER8, except that the guest become very slow and the log files of
>>> the
>>> host are filled with messages (and qemu uses 100% of the CPU). On a
>>> smaller machine like a  PowerMac G5, the machine becomes simply
>>> unusable.
>> It's probably more related to your verbosity level of kernel messages.
>> If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
>> the messages printed to serial which is what's slowing you down.
>>
>> The other problem sounds pretty severe, but the only thing your patch
>> does any different from the current code flow would be the patch below.
>> Or did I miss anything?
>>
>> diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
>> index 5cc2e7a..4672bc2 100644
>> --- a/arch/powerpc/kvm/emulate.c

Re: [PATCH] kvm-pr: manage illegal instructions

[Thomas Huth]

On 18.05.2016 12:18, Thomas Huth wrote:
> On 17.05.2016 19:49, Laurent Vivier wrote:
>>
>>
>> On 17/05/2016 10:37, Alexander Graf wrote:
>>> On 05/17/2016 10:35 AM, Laurent Vivier wrote:

 On 12/05/2016 16:23, Laurent Vivier wrote:
>
> On 12/05/2016 11:27, Alexander Graf wrote:
>> On 05/12/2016 11:10 AM, Laurent Vivier wrote:
>>> On 11/05/2016 13:49, Alexander Graf wrote:
 On 05/11/2016 01:14 PM, Laurent Vivier wrote:
> On 11/05/2016 12:35, Alexander Graf wrote:
>> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
>>> While writing some instruction tests for kvm-unit-tests for
>>> powerpc,
>>> I've found that illegal instructions are not managed correctly
>>> with
>>> kvm-pr,
>>> while it is fine with kvm-hv.
>>>
>>> When an illegal instruction (like ".long 0") is processed by
>>> kvm-pr,
>>> the kernel logs are filled with:
>>>
>>>  Couldn't emulate instruction 0x (op 0 xop 0)
>>>  kvmppc_handle_exit_pr: emulation at 700 failed ()
>>>
>>> While the exception handler receives an interrupt for each
>>> instruction
>>> executed after the illegal instruction.
>>>
>>> Signed-off-by: Laurent Vivier 
>>> ---
>>>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/powerpc/kvm/book3s_emulate.c
>>> b/arch/powerpc/kvm/book3s_emulate.c
>>> index 2afdb9c..4ee969d 100644
>>> --- a/arch/powerpc/kvm/book3s_emulate.c
>>> +++ b/arch/powerpc/kvm/book3s_emulate.c
>>> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
>>> *run,
>>> struct kvm_vcpu *vcpu,
>>>switch (get_op(inst)) {
>>>  case 0:
>>> -emulated = EMULATE_FAIL;
>>>  if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>>>  (inst == swab32(inst_sc))) {
>>>  /*
>>> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
>>> *run,
>>> struct kvm_vcpu *vcpu,
>>>  kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>>>  kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>>>  emulated = EMULATE_DONE;
>>> +} else {
>>> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>> But isn't that exactly what the semantic of EMULATE_FAIL is?
>> Fixing it
>> up in book3s_emulate.c is definitely the wrong spot.
>>
>> So what is the problem you're trying to solve? Is the SRR0 at the
>> wrong
>> spot or are the log messages the problem?
> No, the problem is the host kernel logs are filled by the message
> and
> the execution hangs. And the host becomes unresponsiveness, even
> after
> the end of the tests.
>
> Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR
> host,
> and check the kernel logs (dmesg), then try to ssh to the host...
 Ok, so the log messages are the problem. Please fix the message
 output
 then - or remove it altogether. Or if you like, create a module
 parameter that allows you to emit them.

 I personally think the best solution would be to just convert the
 message into a trace point.

 While at it, please see whether the guest can trigger similar host
 log
 output excess in other code paths.
>>> The problem is not really with the log messages: they are
>>> consequence of
>>> the bug I try to fix.
>>>
>>> What happens is once kvm_pr decodes an invalid instruction all the
>>> valid
>>> following instructions trigger a Program exception to the guest
>>> (but are
>>> executed correctly). It has no real consequence on big machine like
>>> POWER8, except that the guest become very slow and the log files of
>>> the
>>> host are filled with messages (and qemu uses 100% of the CPU). On a
>>> smaller machine like a  PowerMac G5, the machine becomes simply
>>> unusable.
>> It's probably more related to your verbosity level of kernel messages.
>> If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
>> the messages printed to serial which is what's slowing you down.
>>
>> The other problem sounds pretty severe, but the only thing your patch
>> does any different from the current code flow would be the patch below.
>> Or did I miss anything?
>>
>> diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
>> index 5cc2e7a..4672bc2 100644
>> --- a/arch/powerpc/kvm/emulate.c
>> +++ 

Re: [PATCH] kvm-pr: manage illegal instructions

[Thomas Huth]

On 17.05.2016 19:49, Laurent Vivier wrote:
> 
> 
> On 17/05/2016 10:37, Alexander Graf wrote:
>> On 05/17/2016 10:35 AM, Laurent Vivier wrote:
>>>
>>> On 12/05/2016 16:23, Laurent Vivier wrote:

 On 12/05/2016 11:27, Alexander Graf wrote:
> On 05/12/2016 11:10 AM, Laurent Vivier wrote:
>> On 11/05/2016 13:49, Alexander Graf wrote:
>>> On 05/11/2016 01:14 PM, Laurent Vivier wrote:
 On 11/05/2016 12:35, Alexander Graf wrote:
> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
>> While writing some instruction tests for kvm-unit-tests for
>> powerpc,
>> I've found that illegal instructions are not managed correctly
>> with
>> kvm-pr,
>> while it is fine with kvm-hv.
>>
>> When an illegal instruction (like ".long 0") is processed by
>> kvm-pr,
>> the kernel logs are filled with:
>>
>>  Couldn't emulate instruction 0x (op 0 xop 0)
>>  kvmppc_handle_exit_pr: emulation at 700 failed ()
>>
>> While the exception handler receives an interrupt for each
>> instruction
>> executed after the illegal instruction.
>>
>> Signed-off-by: Laurent Vivier 
>> ---
>>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kvm/book3s_emulate.c
>> b/arch/powerpc/kvm/book3s_emulate.c
>> index 2afdb9c..4ee969d 100644
>> --- a/arch/powerpc/kvm/book3s_emulate.c
>> +++ b/arch/powerpc/kvm/book3s_emulate.c
>> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
>> *run,
>> struct kvm_vcpu *vcpu,
>>switch (get_op(inst)) {
>>  case 0:
>> -emulated = EMULATE_FAIL;
>>  if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>>  (inst == swab32(inst_sc))) {
>>  /*
>> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
>> *run,
>> struct kvm_vcpu *vcpu,
>>  kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>>  kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>>  emulated = EMULATE_DONE;
>> +} else {
>> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> But isn't that exactly what the semantic of EMULATE_FAIL is?
> Fixing it
> up in book3s_emulate.c is definitely the wrong spot.
>
> So what is the problem you're trying to solve? Is the SRR0 at the
> wrong
> spot or are the log messages the problem?
 No, the problem is the host kernel logs are filled by the message
 and
 the execution hangs. And the host becomes unresponsiveness, even
 after
 the end of the tests.

 Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR
 host,
 and check the kernel logs (dmesg), then try to ssh to the host...
>>> Ok, so the log messages are the problem. Please fix the message
>>> output
>>> then - or remove it altogether. Or if you like, create a module
>>> parameter that allows you to emit them.
>>>
>>> I personally think the best solution would be to just convert the
>>> message into a trace point.
>>>
>>> While at it, please see whether the guest can trigger similar host
>>> log
>>> output excess in other code paths.
>> The problem is not really with the log messages: they are
>> consequence of
>> the bug I try to fix.
>>
>> What happens is once kvm_pr decodes an invalid instruction all the
>> valid
>> following instructions trigger a Program exception to the guest
>> (but are
>> executed correctly). It has no real consequence on big machine like
>> POWER8, except that the guest become very slow and the log files of
>> the
>> host are filled with messages (and qemu uses 100% of the CPU). On a
>> smaller machine like a  PowerMac G5, the machine becomes simply
>> unusable.
> It's probably more related to your verbosity level of kernel messages.
> If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
> the messages printed to serial which is what's slowing you down.
>
> The other problem sounds pretty severe, but the only thing your patch
> does any different from the current code flow would be the patch below.
> Or did I miss anything?
>
> diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
> index 5cc2e7a..4672bc2 100644
> --- a/arch/powerpc/kvm/emulate.c
> +++ b/arch/powerpc/kvm/emulate.c
> @@ -302,7 +302,11 @@ int kvmppc_emulate_instruction(struct kvm_run
> *run,
> struct kvm_vcpu 

Re: [PATCH] kvm-pr: manage illegal instructions

[Thomas Huth]

On 17.05.2016 19:49, Laurent Vivier wrote:
> 
> 
> On 17/05/2016 10:37, Alexander Graf wrote:
>> On 05/17/2016 10:35 AM, Laurent Vivier wrote:
>>>
>>> On 12/05/2016 16:23, Laurent Vivier wrote:

 On 12/05/2016 11:27, Alexander Graf wrote:
> On 05/12/2016 11:10 AM, Laurent Vivier wrote:
>> On 11/05/2016 13:49, Alexander Graf wrote:
>>> On 05/11/2016 01:14 PM, Laurent Vivier wrote:
 On 11/05/2016 12:35, Alexander Graf wrote:
> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
>> While writing some instruction tests for kvm-unit-tests for
>> powerpc,
>> I've found that illegal instructions are not managed correctly
>> with
>> kvm-pr,
>> while it is fine with kvm-hv.
>>
>> When an illegal instruction (like ".long 0") is processed by
>> kvm-pr,
>> the kernel logs are filled with:
>>
>>  Couldn't emulate instruction 0x (op 0 xop 0)
>>  kvmppc_handle_exit_pr: emulation at 700 failed ()
>>
>> While the exception handler receives an interrupt for each
>> instruction
>> executed after the illegal instruction.
>>
>> Signed-off-by: Laurent Vivier 
>> ---
>>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kvm/book3s_emulate.c
>> b/arch/powerpc/kvm/book3s_emulate.c
>> index 2afdb9c..4ee969d 100644
>> --- a/arch/powerpc/kvm/book3s_emulate.c
>> +++ b/arch/powerpc/kvm/book3s_emulate.c
>> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
>> *run,
>> struct kvm_vcpu *vcpu,
>>switch (get_op(inst)) {
>>  case 0:
>> -emulated = EMULATE_FAIL;
>>  if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>>  (inst == swab32(inst_sc))) {
>>  /*
>> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
>> *run,
>> struct kvm_vcpu *vcpu,
>>  kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>>  kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>>  emulated = EMULATE_DONE;
>> +} else {
>> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> But isn't that exactly what the semantic of EMULATE_FAIL is?
> Fixing it
> up in book3s_emulate.c is definitely the wrong spot.
>
> So what is the problem you're trying to solve? Is the SRR0 at the
> wrong
> spot or are the log messages the problem?
 No, the problem is the host kernel logs are filled by the message
 and
 the execution hangs. And the host becomes unresponsiveness, even
 after
 the end of the tests.

 Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR
 host,
 and check the kernel logs (dmesg), then try to ssh to the host...
>>> Ok, so the log messages are the problem. Please fix the message
>>> output
>>> then - or remove it altogether. Or if you like, create a module
>>> parameter that allows you to emit them.
>>>
>>> I personally think the best solution would be to just convert the
>>> message into a trace point.
>>>
>>> While at it, please see whether the guest can trigger similar host
>>> log
>>> output excess in other code paths.
>> The problem is not really with the log messages: they are
>> consequence of
>> the bug I try to fix.
>>
>> What happens is once kvm_pr decodes an invalid instruction all the
>> valid
>> following instructions trigger a Program exception to the guest
>> (but are
>> executed correctly). It has no real consequence on big machine like
>> POWER8, except that the guest become very slow and the log files of
>> the
>> host are filled with messages (and qemu uses 100% of the CPU). On a
>> smaller machine like a  PowerMac G5, the machine becomes simply
>> unusable.
> It's probably more related to your verbosity level of kernel messages.
> If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
> the messages printed to serial which is what's slowing you down.
>
> The other problem sounds pretty severe, but the only thing your patch
> does any different from the current code flow would be the patch below.
> Or did I miss anything?
>
> diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
> index 5cc2e7a..4672bc2 100644
> --- a/arch/powerpc/kvm/emulate.c
> +++ b/arch/powerpc/kvm/emulate.c
> @@ -302,7 +302,11 @@ int kvmppc_emulate_instruction(struct kvm_run
> *run,
> struct kvm_vcpu *vcpu)
> 

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

On 17/05/2016 10:37, Alexander Graf wrote:
> On 05/17/2016 10:35 AM, Laurent Vivier wrote:
>>
>> On 12/05/2016 16:23, Laurent Vivier wrote:
>>>
>>> On 12/05/2016 11:27, Alexander Graf wrote:
 On 05/12/2016 11:10 AM, Laurent Vivier wrote:
> On 11/05/2016 13:49, Alexander Graf wrote:
>> On 05/11/2016 01:14 PM, Laurent Vivier wrote:
>>> On 11/05/2016 12:35, Alexander Graf wrote:
 On 03/15/2016 09:18 PM, Laurent Vivier wrote:
> While writing some instruction tests for kvm-unit-tests for
> powerpc,
> I've found that illegal instructions are not managed correctly
> with
> kvm-pr,
> while it is fine with kvm-hv.
>
> When an illegal instruction (like ".long 0") is processed by
> kvm-pr,
> the kernel logs are filled with:
>
>  Couldn't emulate instruction 0x (op 0 xop 0)
>  kvmppc_handle_exit_pr: emulation at 700 failed ()
>
> While the exception handler receives an interrupt for each
> instruction
> executed after the illegal instruction.
>
> Signed-off-by: Laurent Vivier 
> ---
>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/kvm/book3s_emulate.c
> b/arch/powerpc/kvm/book3s_emulate.c
> index 2afdb9c..4ee969d 100644
> --- a/arch/powerpc/kvm/book3s_emulate.c
> +++ b/arch/powerpc/kvm/book3s_emulate.c
> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
> *run,
> struct kvm_vcpu *vcpu,
>switch (get_op(inst)) {
>  case 0:
> -emulated = EMULATE_FAIL;
>  if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>  (inst == swab32(inst_sc))) {
>  /*
> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
> *run,
> struct kvm_vcpu *vcpu,
>  kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>  kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>  emulated = EMULATE_DONE;
> +} else {
> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
 But isn't that exactly what the semantic of EMULATE_FAIL is?
 Fixing it
 up in book3s_emulate.c is definitely the wrong spot.

 So what is the problem you're trying to solve? Is the SRR0 at the
 wrong
 spot or are the log messages the problem?
>>> No, the problem is the host kernel logs are filled by the message
>>> and
>>> the execution hangs. And the host becomes unresponsiveness, even
>>> after
>>> the end of the tests.
>>>
>>> Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR
>>> host,
>>> and check the kernel logs (dmesg), then try to ssh to the host...
>> Ok, so the log messages are the problem. Please fix the message
>> output
>> then - or remove it altogether. Or if you like, create a module
>> parameter that allows you to emit them.
>>
>> I personally think the best solution would be to just convert the
>> message into a trace point.
>>
>> While at it, please see whether the guest can trigger similar host
>> log
>> output excess in other code paths.
> The problem is not really with the log messages: they are
> consequence of
> the bug I try to fix.
>
> What happens is once kvm_pr decodes an invalid instruction all the
> valid
> following instructions trigger a Program exception to the guest
> (but are
> executed correctly). It has no real consequence on big machine like
> POWER8, except that the guest become very slow and the log files of
> the
> host are filled with messages (and qemu uses 100% of the CPU). On a
> smaller machine like a  PowerMac G5, the machine becomes simply
> unusable.
 It's probably more related to your verbosity level of kernel messages.
 If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
 the messages printed to serial which is what's slowing you down.

 The other problem sounds pretty severe, but the only thing your patch
 does any different from the current code flow would be the patch below.
 Or did I miss anything?

 diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
 index 5cc2e7a..4672bc2 100644
 --- a/arch/powerpc/kvm/emulate.c
 +++ b/arch/powerpc/kvm/emulate.c
 @@ -302,7 +302,11 @@ int kvmppc_emulate_instruction(struct kvm_run
 *run,
 struct kvm_vcpu *vcpu)
  advance = 0;
  printk(KERN_ERR "Couldn't emulate instruction
 0x%08x "
 

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

On 17/05/2016 10:37, Alexander Graf wrote:
> On 05/17/2016 10:35 AM, Laurent Vivier wrote:
>>
>> On 12/05/2016 16:23, Laurent Vivier wrote:
>>>
>>> On 12/05/2016 11:27, Alexander Graf wrote:
 On 05/12/2016 11:10 AM, Laurent Vivier wrote:
> On 11/05/2016 13:49, Alexander Graf wrote:
>> On 05/11/2016 01:14 PM, Laurent Vivier wrote:
>>> On 11/05/2016 12:35, Alexander Graf wrote:
 On 03/15/2016 09:18 PM, Laurent Vivier wrote:
> While writing some instruction tests for kvm-unit-tests for
> powerpc,
> I've found that illegal instructions are not managed correctly
> with
> kvm-pr,
> while it is fine with kvm-hv.
>
> When an illegal instruction (like ".long 0") is processed by
> kvm-pr,
> the kernel logs are filled with:
>
>  Couldn't emulate instruction 0x (op 0 xop 0)
>  kvmppc_handle_exit_pr: emulation at 700 failed ()
>
> While the exception handler receives an interrupt for each
> instruction
> executed after the illegal instruction.
>
> Signed-off-by: Laurent Vivier 
> ---
>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/kvm/book3s_emulate.c
> b/arch/powerpc/kvm/book3s_emulate.c
> index 2afdb9c..4ee969d 100644
> --- a/arch/powerpc/kvm/book3s_emulate.c
> +++ b/arch/powerpc/kvm/book3s_emulate.c
> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
> *run,
> struct kvm_vcpu *vcpu,
>switch (get_op(inst)) {
>  case 0:
> -emulated = EMULATE_FAIL;
>  if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>  (inst == swab32(inst_sc))) {
>  /*
> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
> *run,
> struct kvm_vcpu *vcpu,
>  kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>  kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>  emulated = EMULATE_DONE;
> +} else {
> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
 But isn't that exactly what the semantic of EMULATE_FAIL is?
 Fixing it
 up in book3s_emulate.c is definitely the wrong spot.

 So what is the problem you're trying to solve? Is the SRR0 at the
 wrong
 spot or are the log messages the problem?
>>> No, the problem is the host kernel logs are filled by the message
>>> and
>>> the execution hangs. And the host becomes unresponsiveness, even
>>> after
>>> the end of the tests.
>>>
>>> Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR
>>> host,
>>> and check the kernel logs (dmesg), then try to ssh to the host...
>> Ok, so the log messages are the problem. Please fix the message
>> output
>> then - or remove it altogether. Or if you like, create a module
>> parameter that allows you to emit them.
>>
>> I personally think the best solution would be to just convert the
>> message into a trace point.
>>
>> While at it, please see whether the guest can trigger similar host
>> log
>> output excess in other code paths.
> The problem is not really with the log messages: they are
> consequence of
> the bug I try to fix.
>
> What happens is once kvm_pr decodes an invalid instruction all the
> valid
> following instructions trigger a Program exception to the guest
> (but are
> executed correctly). It has no real consequence on big machine like
> POWER8, except that the guest become very slow and the log files of
> the
> host are filled with messages (and qemu uses 100% of the CPU). On a
> smaller machine like a  PowerMac G5, the machine becomes simply
> unusable.
 It's probably more related to your verbosity level of kernel messages.
 If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
 the messages printed to serial which is what's slowing you down.

 The other problem sounds pretty severe, but the only thing your patch
 does any different from the current code flow would be the patch below.
 Or did I miss anything?

 diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
 index 5cc2e7a..4672bc2 100644
 --- a/arch/powerpc/kvm/emulate.c
 +++ b/arch/powerpc/kvm/emulate.c
 @@ -302,7 +302,11 @@ int kvmppc_emulate_instruction(struct kvm_run
 *run,
 struct kvm_vcpu *vcpu)
  advance = 0;
  printk(KERN_ERR "Couldn't emulate instruction
 0x%08x "
 "(op %d 

Re: [PATCH] kvm-pr: manage illegal instructions

[Alexander Graf]

On 05/17/2016 10:35 AM, Laurent Vivier wrote:


On 12/05/2016 16:23, Laurent Vivier wrote:


On 12/05/2016 11:27, Alexander Graf wrote:

On 05/12/2016 11:10 AM, Laurent Vivier wrote:

On 11/05/2016 13:49, Alexander Graf wrote:

On 05/11/2016 01:14 PM, Laurent Vivier wrote:

On 11/05/2016 12:35, Alexander Graf wrote:

On 03/15/2016 09:18 PM, Laurent Vivier wrote:

While writing some instruction tests for kvm-unit-tests for powerpc,
I've found that illegal instructions are not managed correctly with
kvm-pr,
while it is fine with kvm-hv.

When an illegal instruction (like ".long 0") is processed by kvm-pr,
the kernel logs are filled with:

 Couldn't emulate instruction 0x (op 0 xop 0)
 kvmppc_handle_exit_pr: emulation at 700 failed ()

While the exception handler receives an interrupt for each
instruction
executed after the illegal instruction.

Signed-off-by: Laurent Vivier 
---
 arch/powerpc/kvm/book3s_emulate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_emulate.c
b/arch/powerpc/kvm/book3s_emulate.c
index 2afdb9c..4ee969d 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
struct kvm_vcpu *vcpu,
   switch (get_op(inst)) {
 case 0:
-emulated = EMULATE_FAIL;
 if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
 (inst == swab32(inst_sc))) {
 /*
@@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
*run,
struct kvm_vcpu *vcpu,
 kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
 kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
 emulated = EMULATE_DONE;
+} else {
+kvmppc_core_queue_program(vcpu, SRR1_PROGILL);

But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
up in book3s_emulate.c is definitely the wrong spot.

So what is the problem you're trying to solve? Is the SRR0 at the
wrong
spot or are the log messages the problem?

No, the problem is the host kernel logs are filled by the message and
the execution hangs. And the host becomes unresponsiveness, even after
the end of the tests.

Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
and check the kernel logs (dmesg), then try to ssh to the host...

Ok, so the log messages are the problem. Please fix the message output
then - or remove it altogether. Or if you like, create a module
parameter that allows you to emit them.

I personally think the best solution would be to just convert the
message into a trace point.

While at it, please see whether the guest can trigger similar host log
output excess in other code paths.

The problem is not really with the log messages: they are consequence of
the bug I try to fix.

What happens is once kvm_pr decodes an invalid instruction all the valid
following instructions trigger a Program exception to the guest (but are
executed correctly). It has no real consequence on big machine like
POWER8, except that the guest become very slow and the log files of the
host are filled with messages (and qemu uses 100% of the CPU). On a
smaller machine like a  PowerMac G5, the machine becomes simply unusable.

It's probably more related to your verbosity level of kernel messages.
If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
the messages printed to serial which is what's slowing you down.

The other problem sounds pretty severe, but the only thing your patch
does any different from the current code flow would be the patch below.
Or did I miss anything?

diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index 5cc2e7a..4672bc2 100644
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -302,7 +302,11 @@ int kvmppc_emulate_instruction(struct kvm_run *run,
struct kvm_vcpu *vcpu)
 advance = 0;
 printk(KERN_ERR "Couldn't emulate instruction
0x%08x "
"(op %d xop %d)\n", inst, get_op(inst),
get_xop(inst));
+#ifdef CONFIG_PPC_BOOK3S
+   kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
+#else
 kvmppc_core_queue_program(vcpu, 0);
+#endif
 }
 }


Do you want I send an updated patch with your changes?


Well, you reported the issue and narrowed it down, so feel free to send 
it under your name :). I merely simplified your patch a bit.



Alex

Re: [PATCH] kvm-pr: manage illegal instructions

[Alexander Graf]

On 05/17/2016 10:35 AM, Laurent Vivier wrote:


On 12/05/2016 16:23, Laurent Vivier wrote:


On 12/05/2016 11:27, Alexander Graf wrote:

On 05/12/2016 11:10 AM, Laurent Vivier wrote:

On 11/05/2016 13:49, Alexander Graf wrote:

On 05/11/2016 01:14 PM, Laurent Vivier wrote:

On 11/05/2016 12:35, Alexander Graf wrote:

On 03/15/2016 09:18 PM, Laurent Vivier wrote:

While writing some instruction tests for kvm-unit-tests for powerpc,
I've found that illegal instructions are not managed correctly with
kvm-pr,
while it is fine with kvm-hv.

When an illegal instruction (like ".long 0") is processed by kvm-pr,
the kernel logs are filled with:

 Couldn't emulate instruction 0x (op 0 xop 0)
 kvmppc_handle_exit_pr: emulation at 700 failed ()

While the exception handler receives an interrupt for each
instruction
executed after the illegal instruction.

Signed-off-by: Laurent Vivier 
---
 arch/powerpc/kvm/book3s_emulate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_emulate.c
b/arch/powerpc/kvm/book3s_emulate.c
index 2afdb9c..4ee969d 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
struct kvm_vcpu *vcpu,
   switch (get_op(inst)) {
 case 0:
-emulated = EMULATE_FAIL;
 if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
 (inst == swab32(inst_sc))) {
 /*
@@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
*run,
struct kvm_vcpu *vcpu,
 kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
 kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
 emulated = EMULATE_DONE;
+} else {
+kvmppc_core_queue_program(vcpu, SRR1_PROGILL);

But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
up in book3s_emulate.c is definitely the wrong spot.

So what is the problem you're trying to solve? Is the SRR0 at the
wrong
spot or are the log messages the problem?

No, the problem is the host kernel logs are filled by the message and
the execution hangs. And the host becomes unresponsiveness, even after
the end of the tests.

Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
and check the kernel logs (dmesg), then try to ssh to the host...

Ok, so the log messages are the problem. Please fix the message output
then - or remove it altogether. Or if you like, create a module
parameter that allows you to emit them.

I personally think the best solution would be to just convert the
message into a trace point.

While at it, please see whether the guest can trigger similar host log
output excess in other code paths.

The problem is not really with the log messages: they are consequence of
the bug I try to fix.

What happens is once kvm_pr decodes an invalid instruction all the valid
following instructions trigger a Program exception to the guest (but are
executed correctly). It has no real consequence on big machine like
POWER8, except that the guest become very slow and the log files of the
host are filled with messages (and qemu uses 100% of the CPU). On a
smaller machine like a  PowerMac G5, the machine becomes simply unusable.

It's probably more related to your verbosity level of kernel messages.
If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
the messages printed to serial which is what's slowing you down.

The other problem sounds pretty severe, but the only thing your patch
does any different from the current code flow would be the patch below.
Or did I miss anything?

diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index 5cc2e7a..4672bc2 100644
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -302,7 +302,11 @@ int kvmppc_emulate_instruction(struct kvm_run *run,
struct kvm_vcpu *vcpu)
 advance = 0;
 printk(KERN_ERR "Couldn't emulate instruction
0x%08x "
"(op %d xop %d)\n", inst, get_op(inst),
get_xop(inst));
+#ifdef CONFIG_PPC_BOOK3S
+   kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
+#else
 kvmppc_core_queue_program(vcpu, 0);
+#endif
 }
 }


Do you want I send an updated patch with your changes?


Well, you reported the issue and narrowed it down, so feel free to send 
it under your name :). I merely simplified your patch a bit.



Alex

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

On 12/05/2016 16:23, Laurent Vivier wrote:
> 
> 
> On 12/05/2016 11:27, Alexander Graf wrote:
>> On 05/12/2016 11:10 AM, Laurent Vivier wrote:
>>>
>>> On 11/05/2016 13:49, Alexander Graf wrote:
 On 05/11/2016 01:14 PM, Laurent Vivier wrote:
> On 11/05/2016 12:35, Alexander Graf wrote:
>> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
>>> While writing some instruction tests for kvm-unit-tests for powerpc,
>>> I've found that illegal instructions are not managed correctly with
>>> kvm-pr,
>>> while it is fine with kvm-hv.
>>>
>>> When an illegal instruction (like ".long 0") is processed by kvm-pr,
>>> the kernel logs are filled with:
>>>
>>> Couldn't emulate instruction 0x (op 0 xop 0)
>>> kvmppc_handle_exit_pr: emulation at 700 failed ()
>>>
>>> While the exception handler receives an interrupt for each
>>> instruction
>>> executed after the illegal instruction.
>>>
>>> Signed-off-by: Laurent Vivier 
>>> ---
>>> arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/powerpc/kvm/book3s_emulate.c
>>> b/arch/powerpc/kvm/book3s_emulate.c
>>> index 2afdb9c..4ee969d 100644
>>> --- a/arch/powerpc/kvm/book3s_emulate.c
>>> +++ b/arch/powerpc/kvm/book3s_emulate.c
>>> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
>>> struct kvm_vcpu *vcpu,
>>>   switch (get_op(inst)) {
>>> case 0:
>>> -emulated = EMULATE_FAIL;
>>> if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>>> (inst == swab32(inst_sc))) {
>>> /*
>>> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
>>> *run,
>>> struct kvm_vcpu *vcpu,
>>> kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>>> kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>>> emulated = EMULATE_DONE;
>>> +} else {
>>> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>> But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
>> up in book3s_emulate.c is definitely the wrong spot.
>>
>> So what is the problem you're trying to solve? Is the SRR0 at the
>> wrong
>> spot or are the log messages the problem?
> No, the problem is the host kernel logs are filled by the message and
> the execution hangs. And the host becomes unresponsiveness, even after
> the end of the tests.
>
> Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
> and check the kernel logs (dmesg), then try to ssh to the host...
 Ok, so the log messages are the problem. Please fix the message output
 then - or remove it altogether. Or if you like, create a module
 parameter that allows you to emit them.

 I personally think the best solution would be to just convert the
 message into a trace point.

 While at it, please see whether the guest can trigger similar host log
 output excess in other code paths.
>>> The problem is not really with the log messages: they are consequence of
>>> the bug I try to fix.
>>>
>>> What happens is once kvm_pr decodes an invalid instruction all the valid
>>> following instructions trigger a Program exception to the guest (but are
>>> executed correctly). It has no real consequence on big machine like
>>> POWER8, except that the guest become very slow and the log files of the
>>> host are filled with messages (and qemu uses 100% of the CPU). On a
>>> smaller machine like a  PowerMac G5, the machine becomes simply unusable.
>>
>> It's probably more related to your verbosity level of kernel messages.
>> If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
>> the messages printed to serial which is what's slowing you down.
>>
>> The other problem sounds pretty severe, but the only thing your patch
>> does any different from the current code flow would be the patch below.
>> Or did I miss anything?
>>
>> diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
>> index 5cc2e7a..4672bc2 100644
>> --- a/arch/powerpc/kvm/emulate.c
>> +++ b/arch/powerpc/kvm/emulate.c
>> @@ -302,7 +302,11 @@ int kvmppc_emulate_instruction(struct kvm_run *run,
>> struct kvm_vcpu *vcpu)
>> advance = 0;
>> printk(KERN_ERR "Couldn't emulate instruction
>> 0x%08x "
>>"(op %d xop %d)\n", inst, get_op(inst),
>> get_xop(inst));
>> +#ifdef CONFIG_PPC_BOOK3S
>> +   kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>> +#else
>> kvmppc_core_queue_program(vcpu, 0);
>> +#endif
>> }
>> }
>>

Do you want I send an updated patch with your changes?

Laurent

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

On 12/05/2016 16:23, Laurent Vivier wrote:
> 
> 
> On 12/05/2016 11:27, Alexander Graf wrote:
>> On 05/12/2016 11:10 AM, Laurent Vivier wrote:
>>>
>>> On 11/05/2016 13:49, Alexander Graf wrote:
 On 05/11/2016 01:14 PM, Laurent Vivier wrote:
> On 11/05/2016 12:35, Alexander Graf wrote:
>> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
>>> While writing some instruction tests for kvm-unit-tests for powerpc,
>>> I've found that illegal instructions are not managed correctly with
>>> kvm-pr,
>>> while it is fine with kvm-hv.
>>>
>>> When an illegal instruction (like ".long 0") is processed by kvm-pr,
>>> the kernel logs are filled with:
>>>
>>> Couldn't emulate instruction 0x (op 0 xop 0)
>>> kvmppc_handle_exit_pr: emulation at 700 failed ()
>>>
>>> While the exception handler receives an interrupt for each
>>> instruction
>>> executed after the illegal instruction.
>>>
>>> Signed-off-by: Laurent Vivier 
>>> ---
>>> arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/powerpc/kvm/book3s_emulate.c
>>> b/arch/powerpc/kvm/book3s_emulate.c
>>> index 2afdb9c..4ee969d 100644
>>> --- a/arch/powerpc/kvm/book3s_emulate.c
>>> +++ b/arch/powerpc/kvm/book3s_emulate.c
>>> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
>>> struct kvm_vcpu *vcpu,
>>>   switch (get_op(inst)) {
>>> case 0:
>>> -emulated = EMULATE_FAIL;
>>> if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>>> (inst == swab32(inst_sc))) {
>>> /*
>>> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
>>> *run,
>>> struct kvm_vcpu *vcpu,
>>> kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>>> kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>>> emulated = EMULATE_DONE;
>>> +} else {
>>> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>> But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
>> up in book3s_emulate.c is definitely the wrong spot.
>>
>> So what is the problem you're trying to solve? Is the SRR0 at the
>> wrong
>> spot or are the log messages the problem?
> No, the problem is the host kernel logs are filled by the message and
> the execution hangs. And the host becomes unresponsiveness, even after
> the end of the tests.
>
> Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
> and check the kernel logs (dmesg), then try to ssh to the host...
 Ok, so the log messages are the problem. Please fix the message output
 then - or remove it altogether. Or if you like, create a module
 parameter that allows you to emit them.

 I personally think the best solution would be to just convert the
 message into a trace point.

 While at it, please see whether the guest can trigger similar host log
 output excess in other code paths.
>>> The problem is not really with the log messages: they are consequence of
>>> the bug I try to fix.
>>>
>>> What happens is once kvm_pr decodes an invalid instruction all the valid
>>> following instructions trigger a Program exception to the guest (but are
>>> executed correctly). It has no real consequence on big machine like
>>> POWER8, except that the guest become very slow and the log files of the
>>> host are filled with messages (and qemu uses 100% of the CPU). On a
>>> smaller machine like a  PowerMac G5, the machine becomes simply unusable.
>>
>> It's probably more related to your verbosity level of kernel messages.
>> If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
>> the messages printed to serial which is what's slowing you down.
>>
>> The other problem sounds pretty severe, but the only thing your patch
>> does any different from the current code flow would be the patch below.
>> Or did I miss anything?
>>
>> diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
>> index 5cc2e7a..4672bc2 100644
>> --- a/arch/powerpc/kvm/emulate.c
>> +++ b/arch/powerpc/kvm/emulate.c
>> @@ -302,7 +302,11 @@ int kvmppc_emulate_instruction(struct kvm_run *run,
>> struct kvm_vcpu *vcpu)
>> advance = 0;
>> printk(KERN_ERR "Couldn't emulate instruction
>> 0x%08x "
>>"(op %d xop %d)\n", inst, get_op(inst),
>> get_xop(inst));
>> +#ifdef CONFIG_PPC_BOOK3S
>> +   kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>> +#else
>> kvmppc_core_queue_program(vcpu, 0);
>> +#endif
>> }
>> }
>>

Do you want I send an updated patch with your changes?

Laurent

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

On 12/05/2016 11:27, Alexander Graf wrote:
> On 05/12/2016 11:10 AM, Laurent Vivier wrote:
>>
>> On 11/05/2016 13:49, Alexander Graf wrote:
>>> On 05/11/2016 01:14 PM, Laurent Vivier wrote:
 On 11/05/2016 12:35, Alexander Graf wrote:
> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
>> While writing some instruction tests for kvm-unit-tests for powerpc,
>> I've found that illegal instructions are not managed correctly with
>> kvm-pr,
>> while it is fine with kvm-hv.
>>
>> When an illegal instruction (like ".long 0") is processed by kvm-pr,
>> the kernel logs are filled with:
>>
>> Couldn't emulate instruction 0x (op 0 xop 0)
>> kvmppc_handle_exit_pr: emulation at 700 failed ()
>>
>> While the exception handler receives an interrupt for each
>> instruction
>> executed after the illegal instruction.
>>
>> Signed-off-by: Laurent Vivier 
>> ---
>> arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kvm/book3s_emulate.c
>> b/arch/powerpc/kvm/book3s_emulate.c
>> index 2afdb9c..4ee969d 100644
>> --- a/arch/powerpc/kvm/book3s_emulate.c
>> +++ b/arch/powerpc/kvm/book3s_emulate.c
>> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
>> struct kvm_vcpu *vcpu,
>>   switch (get_op(inst)) {
>> case 0:
>> -emulated = EMULATE_FAIL;
>> if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>> (inst == swab32(inst_sc))) {
>> /*
>> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
>> *run,
>> struct kvm_vcpu *vcpu,
>> kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>> kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>> emulated = EMULATE_DONE;
>> +} else {
>> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
> up in book3s_emulate.c is definitely the wrong spot.
>
> So what is the problem you're trying to solve? Is the SRR0 at the
> wrong
> spot or are the log messages the problem?
 No, the problem is the host kernel logs are filled by the message and
 the execution hangs. And the host becomes unresponsiveness, even after
 the end of the tests.

 Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
 and check the kernel logs (dmesg), then try to ssh to the host...
>>> Ok, so the log messages are the problem. Please fix the message output
>>> then - or remove it altogether. Or if you like, create a module
>>> parameter that allows you to emit them.
>>>
>>> I personally think the best solution would be to just convert the
>>> message into a trace point.
>>>
>>> While at it, please see whether the guest can trigger similar host log
>>> output excess in other code paths.
>> The problem is not really with the log messages: they are consequence of
>> the bug I try to fix.
>>
>> What happens is once kvm_pr decodes an invalid instruction all the valid
>> following instructions trigger a Program exception to the guest (but are
>> executed correctly). It has no real consequence on big machine like
>> POWER8, except that the guest become very slow and the log files of the
>> host are filled with messages (and qemu uses 100% of the CPU). On a
>> smaller machine like a  PowerMac G5, the machine becomes simply unusable.
> 
> It's probably more related to your verbosity level of kernel messages.
> If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
> the messages printed to serial which is what's slowing you down.
> 
> The other problem sounds pretty severe, but the only thing your patch
> does any different from the current code flow would be the patch below.
> Or did I miss anything?
> 
> diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
> index 5cc2e7a..4672bc2 100644
> --- a/arch/powerpc/kvm/emulate.c
> +++ b/arch/powerpc/kvm/emulate.c
> @@ -302,7 +302,11 @@ int kvmppc_emulate_instruction(struct kvm_run *run,
> struct kvm_vcpu *vcpu)
> advance = 0;
> printk(KERN_ERR "Couldn't emulate instruction
> 0x%08x "
>"(op %d xop %d)\n", inst, get_op(inst),
> get_xop(inst));
> +#ifdef CONFIG_PPC_BOOK3S
> +   kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> +#else
> kvmppc_core_queue_program(vcpu, 0);
> +#endif
> }
> }
> 

OK, that fixes the problem. Thanks. :)

Could you apply it?

Laurent

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

On 12/05/2016 11:27, Alexander Graf wrote:
> On 05/12/2016 11:10 AM, Laurent Vivier wrote:
>>
>> On 11/05/2016 13:49, Alexander Graf wrote:
>>> On 05/11/2016 01:14 PM, Laurent Vivier wrote:
 On 11/05/2016 12:35, Alexander Graf wrote:
> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
>> While writing some instruction tests for kvm-unit-tests for powerpc,
>> I've found that illegal instructions are not managed correctly with
>> kvm-pr,
>> while it is fine with kvm-hv.
>>
>> When an illegal instruction (like ".long 0") is processed by kvm-pr,
>> the kernel logs are filled with:
>>
>> Couldn't emulate instruction 0x (op 0 xop 0)
>> kvmppc_handle_exit_pr: emulation at 700 failed ()
>>
>> While the exception handler receives an interrupt for each
>> instruction
>> executed after the illegal instruction.
>>
>> Signed-off-by: Laurent Vivier 
>> ---
>> arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kvm/book3s_emulate.c
>> b/arch/powerpc/kvm/book3s_emulate.c
>> index 2afdb9c..4ee969d 100644
>> --- a/arch/powerpc/kvm/book3s_emulate.c
>> +++ b/arch/powerpc/kvm/book3s_emulate.c
>> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
>> struct kvm_vcpu *vcpu,
>>   switch (get_op(inst)) {
>> case 0:
>> -emulated = EMULATE_FAIL;
>> if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>> (inst == swab32(inst_sc))) {
>> /*
>> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run
>> *run,
>> struct kvm_vcpu *vcpu,
>> kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>> kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>> emulated = EMULATE_DONE;
>> +} else {
>> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
> up in book3s_emulate.c is definitely the wrong spot.
>
> So what is the problem you're trying to solve? Is the SRR0 at the
> wrong
> spot or are the log messages the problem?
 No, the problem is the host kernel logs are filled by the message and
 the execution hangs. And the host becomes unresponsiveness, even after
 the end of the tests.

 Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
 and check the kernel logs (dmesg), then try to ssh to the host...
>>> Ok, so the log messages are the problem. Please fix the message output
>>> then - or remove it altogether. Or if you like, create a module
>>> parameter that allows you to emit them.
>>>
>>> I personally think the best solution would be to just convert the
>>> message into a trace point.
>>>
>>> While at it, please see whether the guest can trigger similar host log
>>> output excess in other code paths.
>> The problem is not really with the log messages: they are consequence of
>> the bug I try to fix.
>>
>> What happens is once kvm_pr decodes an invalid instruction all the valid
>> following instructions trigger a Program exception to the guest (but are
>> executed correctly). It has no real consequence on big machine like
>> POWER8, except that the guest become very slow and the log files of the
>> host are filled with messages (and qemu uses 100% of the CPU). On a
>> smaller machine like a  PowerMac G5, the machine becomes simply unusable.
> 
> It's probably more related to your verbosity level of kernel messages.
> If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get
> the messages printed to serial which is what's slowing you down.
> 
> The other problem sounds pretty severe, but the only thing your patch
> does any different from the current code flow would be the patch below.
> Or did I miss anything?
> 
> diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
> index 5cc2e7a..4672bc2 100644
> --- a/arch/powerpc/kvm/emulate.c
> +++ b/arch/powerpc/kvm/emulate.c
> @@ -302,7 +302,11 @@ int kvmppc_emulate_instruction(struct kvm_run *run,
> struct kvm_vcpu *vcpu)
> advance = 0;
> printk(KERN_ERR "Couldn't emulate instruction
> 0x%08x "
>"(op %d xop %d)\n", inst, get_op(inst),
> get_xop(inst));
> +#ifdef CONFIG_PPC_BOOK3S
> +   kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> +#else
> kvmppc_core_queue_program(vcpu, 0);
> +#endif
> }
> }
> 

OK, that fixes the problem. Thanks. :)

Could you apply it?

Laurent

Re: [PATCH] kvm-pr: manage illegal instructions

[Alexander Graf]

On 05/12/2016 11:10 AM, Laurent Vivier wrote:


On 11/05/2016 13:49, Alexander Graf wrote:

On 05/11/2016 01:14 PM, Laurent Vivier wrote:

On 11/05/2016 12:35, Alexander Graf wrote:

On 03/15/2016 09:18 PM, Laurent Vivier wrote:

While writing some instruction tests for kvm-unit-tests for powerpc,
I've found that illegal instructions are not managed correctly with
kvm-pr,
while it is fine with kvm-hv.

When an illegal instruction (like ".long 0") is processed by kvm-pr,
the kernel logs are filled with:

Couldn't emulate instruction 0x (op 0 xop 0)
kvmppc_handle_exit_pr: emulation at 700 failed ()

While the exception handler receives an interrupt for each instruction
executed after the illegal instruction.

Signed-off-by: Laurent Vivier 
---
arch/powerpc/kvm/book3s_emulate.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_emulate.c
b/arch/powerpc/kvm/book3s_emulate.c
index 2afdb9c..4ee969d 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
struct kvm_vcpu *vcpu,
  switch (get_op(inst)) {
case 0:
-emulated = EMULATE_FAIL;
if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
(inst == swab32(inst_sc))) {
/*
@@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
struct kvm_vcpu *vcpu,
kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
emulated = EMULATE_DONE;
+} else {
+kvmppc_core_queue_program(vcpu, SRR1_PROGILL);

But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
up in book3s_emulate.c is definitely the wrong spot.

So what is the problem you're trying to solve? Is the SRR0 at the wrong
spot or are the log messages the problem?

No, the problem is the host kernel logs are filled by the message and
the execution hangs. And the host becomes unresponsiveness, even after
the end of the tests.

Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
and check the kernel logs (dmesg), then try to ssh to the host...

Ok, so the log messages are the problem. Please fix the message output
then - or remove it altogether. Or if you like, create a module
parameter that allows you to emit them.

I personally think the best solution would be to just convert the
message into a trace point.

While at it, please see whether the guest can trigger similar host log
output excess in other code paths.

The problem is not really with the log messages: they are consequence of
the bug I try to fix.

What happens is once kvm_pr decodes an invalid instruction all the valid
following instructions trigger a Program exception to the guest (but are
executed correctly). It has no real consequence on big machine like
POWER8, except that the guest become very slow and the log files of the
host are filled with messages (and qemu uses 100% of the CPU). On a
smaller machine like a  PowerMac G5, the machine becomes simply unusable.


It's probably more related to your verbosity level of kernel messages. 
If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get 
the messages printed to serial which is what's slowing you down.


The other problem sounds pretty severe, but the only thing your patch 
does any different from the current code flow would be the patch below. 
Or did I miss anything?


diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index 5cc2e7a..4672bc2 100644
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -302,7 +302,11 @@ int kvmppc_emulate_instruction(struct kvm_run *run, 
struct kvm_vcpu *vcpu)

advance = 0;
printk(KERN_ERR "Couldn't emulate instruction 
0x%08x "
   "(op %d xop %d)\n", inst, get_op(inst), 
get_xop(inst));

+#ifdef CONFIG_PPC_BOOK3S
+   kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
+#else
kvmppc_core_queue_program(vcpu, 0);
+#endif
}
}

Re: [PATCH] kvm-pr: manage illegal instructions

[Alexander Graf]

On 05/12/2016 11:10 AM, Laurent Vivier wrote:


On 11/05/2016 13:49, Alexander Graf wrote:

On 05/11/2016 01:14 PM, Laurent Vivier wrote:

On 11/05/2016 12:35, Alexander Graf wrote:

On 03/15/2016 09:18 PM, Laurent Vivier wrote:

While writing some instruction tests for kvm-unit-tests for powerpc,
I've found that illegal instructions are not managed correctly with
kvm-pr,
while it is fine with kvm-hv.

When an illegal instruction (like ".long 0") is processed by kvm-pr,
the kernel logs are filled with:

Couldn't emulate instruction 0x (op 0 xop 0)
kvmppc_handle_exit_pr: emulation at 700 failed ()

While the exception handler receives an interrupt for each instruction
executed after the illegal instruction.

Signed-off-by: Laurent Vivier 
---
arch/powerpc/kvm/book3s_emulate.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_emulate.c
b/arch/powerpc/kvm/book3s_emulate.c
index 2afdb9c..4ee969d 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
struct kvm_vcpu *vcpu,
  switch (get_op(inst)) {
case 0:
-emulated = EMULATE_FAIL;
if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
(inst == swab32(inst_sc))) {
/*
@@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
struct kvm_vcpu *vcpu,
kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
emulated = EMULATE_DONE;
+} else {
+kvmppc_core_queue_program(vcpu, SRR1_PROGILL);

But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
up in book3s_emulate.c is definitely the wrong spot.

So what is the problem you're trying to solve? Is the SRR0 at the wrong
spot or are the log messages the problem?

No, the problem is the host kernel logs are filled by the message and
the execution hangs. And the host becomes unresponsiveness, even after
the end of the tests.

Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
and check the kernel logs (dmesg), then try to ssh to the host...

Ok, so the log messages are the problem. Please fix the message output
then - or remove it altogether. Or if you like, create a module
parameter that allows you to emit them.

I personally think the best solution would be to just convert the
message into a trace point.

While at it, please see whether the guest can trigger similar host log
output excess in other code paths.

The problem is not really with the log messages: they are consequence of
the bug I try to fix.

What happens is once kvm_pr decodes an invalid instruction all the valid
following instructions trigger a Program exception to the guest (but are
executed correctly). It has no real consequence on big machine like
POWER8, except that the guest become very slow and the log files of the
host are filled with messages (and qemu uses 100% of the CPU). On a
smaller machine like a  PowerMac G5, the machine becomes simply unusable.


It's probably more related to your verbosity level of kernel messages. 
If you pass loglevel=0 (or quiet) to you kernel cmdline you won't get 
the messages printed to serial which is what's slowing you down.


The other problem sounds pretty severe, but the only thing your patch 
does any different from the current code flow would be the patch below. 
Or did I miss anything?


diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c
index 5cc2e7a..4672bc2 100644
--- a/arch/powerpc/kvm/emulate.c
+++ b/arch/powerpc/kvm/emulate.c
@@ -302,7 +302,11 @@ int kvmppc_emulate_instruction(struct kvm_run *run, 
struct kvm_vcpu *vcpu)

advance = 0;
printk(KERN_ERR "Couldn't emulate instruction 
0x%08x "
   "(op %d xop %d)\n", inst, get_op(inst), 
get_xop(inst));

+#ifdef CONFIG_PPC_BOOK3S
+   kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
+#else
kvmppc_core_queue_program(vcpu, 0);
+#endif
}
}

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

On 11/05/2016 13:49, Alexander Graf wrote:
> On 05/11/2016 01:14 PM, Laurent Vivier wrote:
>>
>> On 11/05/2016 12:35, Alexander Graf wrote:
>>> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
 While writing some instruction tests for kvm-unit-tests for powerpc,
 I've found that illegal instructions are not managed correctly with
 kvm-pr,
 while it is fine with kvm-hv.

 When an illegal instruction (like ".long 0") is processed by kvm-pr,
 the kernel logs are filled with:

Couldn't emulate instruction 0x (op 0 xop 0)
kvmppc_handle_exit_pr: emulation at 700 failed ()

 While the exception handler receives an interrupt for each instruction
 executed after the illegal instruction.

 Signed-off-by: Laurent Vivier 
 ---
arch/powerpc/kvm/book3s_emulate.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

 diff --git a/arch/powerpc/kvm/book3s_emulate.c
 b/arch/powerpc/kvm/book3s_emulate.c
 index 2afdb9c..4ee969d 100644
 --- a/arch/powerpc/kvm/book3s_emulate.c
 +++ b/arch/powerpc/kvm/book3s_emulate.c
 @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
 struct kvm_vcpu *vcpu,
  switch (get_op(inst)) {
case 0:
 -emulated = EMULATE_FAIL;
if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
(inst == swab32(inst_sc))) {
/*
 @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
 struct kvm_vcpu *vcpu,
kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
emulated = EMULATE_DONE;
 +} else {
 +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>>> But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
>>> up in book3s_emulate.c is definitely the wrong spot.
>>>
>>> So what is the problem you're trying to solve? Is the SRR0 at the wrong
>>> spot or are the log messages the problem?
>> No, the problem is the host kernel logs are filled by the message and
>> the execution hangs. And the host becomes unresponsiveness, even after
>> the end of the tests.
>>
>> Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
>> and check the kernel logs (dmesg), then try to ssh to the host...
> 
> Ok, so the log messages are the problem. Please fix the message output
> then - or remove it altogether. Or if you like, create a module
> parameter that allows you to emit them.
> 
> I personally think the best solution would be to just convert the
> message into a trace point.
> 
> While at it, please see whether the guest can trigger similar host log
> output excess in other code paths.

The problem is not really with the log messages: they are consequence of
the bug I try to fix.

What happens is once kvm_pr decodes an invalid instruction all the valid
following instructions trigger a Program exception to the guest (but are
executed correctly). It has no real consequence on big machine like
POWER8, except that the guest become very slow and the log files of the
host are filled with messages (and qemu uses 100% of the CPU). On a
smaller machine like a  PowerMac G5, the machine becomes simply unusable.

Please try kvm-unit-tests to see what happens:

qemu-system-ppc64 -machine pseries,accel=kvm,kvm-type=PR -bios
powerpc/boot_rom.bin -display none -serial stdio -kernel
powerpc/emulator.elf -smp 1 --append "-v"


Thanks,
Laurent

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

On 11/05/2016 13:49, Alexander Graf wrote:
> On 05/11/2016 01:14 PM, Laurent Vivier wrote:
>>
>> On 11/05/2016 12:35, Alexander Graf wrote:
>>> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
 While writing some instruction tests for kvm-unit-tests for powerpc,
 I've found that illegal instructions are not managed correctly with
 kvm-pr,
 while it is fine with kvm-hv.

 When an illegal instruction (like ".long 0") is processed by kvm-pr,
 the kernel logs are filled with:

Couldn't emulate instruction 0x (op 0 xop 0)
kvmppc_handle_exit_pr: emulation at 700 failed ()

 While the exception handler receives an interrupt for each instruction
 executed after the illegal instruction.

 Signed-off-by: Laurent Vivier 
 ---
arch/powerpc/kvm/book3s_emulate.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

 diff --git a/arch/powerpc/kvm/book3s_emulate.c
 b/arch/powerpc/kvm/book3s_emulate.c
 index 2afdb9c..4ee969d 100644
 --- a/arch/powerpc/kvm/book3s_emulate.c
 +++ b/arch/powerpc/kvm/book3s_emulate.c
 @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
 struct kvm_vcpu *vcpu,
  switch (get_op(inst)) {
case 0:
 -emulated = EMULATE_FAIL;
if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
(inst == swab32(inst_sc))) {
/*
 @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
 struct kvm_vcpu *vcpu,
kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
emulated = EMULATE_DONE;
 +} else {
 +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>>> But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
>>> up in book3s_emulate.c is definitely the wrong spot.
>>>
>>> So what is the problem you're trying to solve? Is the SRR0 at the wrong
>>> spot or are the log messages the problem?
>> No, the problem is the host kernel logs are filled by the message and
>> the execution hangs. And the host becomes unresponsiveness, even after
>> the end of the tests.
>>
>> Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
>> and check the kernel logs (dmesg), then try to ssh to the host...
> 
> Ok, so the log messages are the problem. Please fix the message output
> then - or remove it altogether. Or if you like, create a module
> parameter that allows you to emit them.
> 
> I personally think the best solution would be to just convert the
> message into a trace point.
> 
> While at it, please see whether the guest can trigger similar host log
> output excess in other code paths.

The problem is not really with the log messages: they are consequence of
the bug I try to fix.

What happens is once kvm_pr decodes an invalid instruction all the valid
following instructions trigger a Program exception to the guest (but are
executed correctly). It has no real consequence on big machine like
POWER8, except that the guest become very slow and the log files of the
host are filled with messages (and qemu uses 100% of the CPU). On a
smaller machine like a  PowerMac G5, the machine becomes simply unusable.

Please try kvm-unit-tests to see what happens:

qemu-system-ppc64 -machine pseries,accel=kvm,kvm-type=PR -bios
powerpc/boot_rom.bin -display none -serial stdio -kernel
powerpc/emulator.elf -smp 1 --append "-v"


Thanks,
Laurent

Re: [PATCH] kvm-pr: manage illegal instructions

[Alexander Graf]

On 05/11/2016 01:14 PM, Laurent Vivier wrote:


On 11/05/2016 12:35, Alexander Graf wrote:

On 03/15/2016 09:18 PM, Laurent Vivier wrote:

While writing some instruction tests for kvm-unit-tests for powerpc,
I've found that illegal instructions are not managed correctly with
kvm-pr,
while it is fine with kvm-hv.

When an illegal instruction (like ".long 0") is processed by kvm-pr,
the kernel logs are filled with:

   Couldn't emulate instruction 0x (op 0 xop 0)
   kvmppc_handle_exit_pr: emulation at 700 failed ()

While the exception handler receives an interrupt for each instruction
executed after the illegal instruction.

Signed-off-by: Laurent Vivier 
---
   arch/powerpc/kvm/book3s_emulate.c | 4 +++-
   1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_emulate.c
b/arch/powerpc/kvm/book3s_emulate.c
index 2afdb9c..4ee969d 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
struct kvm_vcpu *vcpu,
 switch (get_op(inst)) {
   case 0:
-emulated = EMULATE_FAIL;
   if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
   (inst == swab32(inst_sc))) {
   /*
@@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
struct kvm_vcpu *vcpu,
   kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
   kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
   emulated = EMULATE_DONE;
+} else {
+kvmppc_core_queue_program(vcpu, SRR1_PROGILL);

But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
up in book3s_emulate.c is definitely the wrong spot.

So what is the problem you're trying to solve? Is the SRR0 at the wrong
spot or are the log messages the problem?

No, the problem is the host kernel logs are filled by the message and
the execution hangs. And the host becomes unresponsiveness, even after
the end of the tests.

Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
and check the kernel logs (dmesg), then try to ssh to the host...


Ok, so the log messages are the problem. Please fix the message output 
then - or remove it altogether. Or if you like, create a module 
parameter that allows you to emit them.


I personally think the best solution would be to just convert the 
message into a trace point.


While at it, please see whether the guest can trigger similar host log 
output excess in other code paths.



Alex

Re: [PATCH] kvm-pr: manage illegal instructions

[Alexander Graf]

On 05/11/2016 01:14 PM, Laurent Vivier wrote:


On 11/05/2016 12:35, Alexander Graf wrote:

On 03/15/2016 09:18 PM, Laurent Vivier wrote:

While writing some instruction tests for kvm-unit-tests for powerpc,
I've found that illegal instructions are not managed correctly with
kvm-pr,
while it is fine with kvm-hv.

When an illegal instruction (like ".long 0") is processed by kvm-pr,
the kernel logs are filled with:

   Couldn't emulate instruction 0x (op 0 xop 0)
   kvmppc_handle_exit_pr: emulation at 700 failed ()

While the exception handler receives an interrupt for each instruction
executed after the illegal instruction.

Signed-off-by: Laurent Vivier 
---
   arch/powerpc/kvm/book3s_emulate.c | 4 +++-
   1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_emulate.c
b/arch/powerpc/kvm/book3s_emulate.c
index 2afdb9c..4ee969d 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
struct kvm_vcpu *vcpu,
 switch (get_op(inst)) {
   case 0:
-emulated = EMULATE_FAIL;
   if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
   (inst == swab32(inst_sc))) {
   /*
@@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
struct kvm_vcpu *vcpu,
   kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
   kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
   emulated = EMULATE_DONE;
+} else {
+kvmppc_core_queue_program(vcpu, SRR1_PROGILL);

But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
up in book3s_emulate.c is definitely the wrong spot.

So what is the problem you're trying to solve? Is the SRR0 at the wrong
spot or are the log messages the problem?

No, the problem is the host kernel logs are filled by the message and
the execution hangs. And the host becomes unresponsiveness, even after
the end of the tests.

Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
and check the kernel logs (dmesg), then try to ssh to the host...


Ok, so the log messages are the problem. Please fix the message output 
then - or remove it altogether. Or if you like, create a module 
parameter that allows you to emit them.


I personally think the best solution would be to just convert the 
message into a trace point.


While at it, please see whether the guest can trigger similar host log 
output excess in other code paths.



Alex

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

On 11/05/2016 12:35, Alexander Graf wrote:
> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
>> While writing some instruction tests for kvm-unit-tests for powerpc,
>> I've found that illegal instructions are not managed correctly with
>> kvm-pr,
>> while it is fine with kvm-hv.
>>
>> When an illegal instruction (like ".long 0") is processed by kvm-pr,
>> the kernel logs are filled with:
>>
>>   Couldn't emulate instruction 0x (op 0 xop 0)
>>   kvmppc_handle_exit_pr: emulation at 700 failed ()
>>
>> While the exception handler receives an interrupt for each instruction
>> executed after the illegal instruction.
>>
>> Signed-off-by: Laurent Vivier 
>> ---
>>   arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kvm/book3s_emulate.c
>> b/arch/powerpc/kvm/book3s_emulate.c
>> index 2afdb9c..4ee969d 100644
>> --- a/arch/powerpc/kvm/book3s_emulate.c
>> +++ b/arch/powerpc/kvm/book3s_emulate.c
>> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
>> struct kvm_vcpu *vcpu,
>> switch (get_op(inst)) {
>>   case 0:
>> -emulated = EMULATE_FAIL;
>>   if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>>   (inst == swab32(inst_sc))) {
>>   /*
>> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
>> struct kvm_vcpu *vcpu,
>>   kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>>   kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>>   emulated = EMULATE_DONE;
>> +} else {
>> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> 
> But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
> up in book3s_emulate.c is definitely the wrong spot.
> 
> So what is the problem you're trying to solve? Is the SRR0 at the wrong
> spot or are the log messages the problem?

No, the problem is the host kernel logs are filled by the message and
the execution hangs. And the host becomes unresponsiveness, even after
the end of the tests.

Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
and check the kernel logs (dmesg), then try to ssh to the host...

Laurent

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

On 11/05/2016 12:35, Alexander Graf wrote:
> On 03/15/2016 09:18 PM, Laurent Vivier wrote:
>> While writing some instruction tests for kvm-unit-tests for powerpc,
>> I've found that illegal instructions are not managed correctly with
>> kvm-pr,
>> while it is fine with kvm-hv.
>>
>> When an illegal instruction (like ".long 0") is processed by kvm-pr,
>> the kernel logs are filled with:
>>
>>   Couldn't emulate instruction 0x (op 0 xop 0)
>>   kvmppc_handle_exit_pr: emulation at 700 failed ()
>>
>> While the exception handler receives an interrupt for each instruction
>> executed after the illegal instruction.
>>
>> Signed-off-by: Laurent Vivier 
>> ---
>>   arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kvm/book3s_emulate.c
>> b/arch/powerpc/kvm/book3s_emulate.c
>> index 2afdb9c..4ee969d 100644
>> --- a/arch/powerpc/kvm/book3s_emulate.c
>> +++ b/arch/powerpc/kvm/book3s_emulate.c
>> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
>> struct kvm_vcpu *vcpu,
>> switch (get_op(inst)) {
>>   case 0:
>> -emulated = EMULATE_FAIL;
>>   if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>>   (inst == swab32(inst_sc))) {
>>   /*
>> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run,
>> struct kvm_vcpu *vcpu,
>>   kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>>   kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>>   emulated = EMULATE_DONE;
>> +} else {
>> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> 
> But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it
> up in book3s_emulate.c is definitely the wrong spot.
> 
> So what is the problem you're trying to solve? Is the SRR0 at the wrong
> spot or are the log messages the problem?

No, the problem is the host kernel logs are filled by the message and
the execution hangs. And the host becomes unresponsiveness, even after
the end of the tests.

Please, try to run kvm-unit-tests (the emulator test) on a KVM-PR host,
and check the kernel logs (dmesg), then try to ssh to the host...

Laurent

Re: [PATCH] kvm-pr: manage illegal instructions

[Alexander Graf]

On 03/15/2016 09:18 PM, Laurent Vivier wrote:

While writing some instruction tests for kvm-unit-tests for powerpc,
I've found that illegal instructions are not managed correctly with kvm-pr,
while it is fine with kvm-hv.

When an illegal instruction (like ".long 0") is processed by kvm-pr,
the kernel logs are filled with:

  Couldn't emulate instruction 0x (op 0 xop 0)
  kvmppc_handle_exit_pr: emulation at 700 failed ()

While the exception handler receives an interrupt for each instruction
executed after the illegal instruction.

Signed-off-by: Laurent Vivier 
---
  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_emulate.c 
b/arch/powerpc/kvm/book3s_emulate.c
index 2afdb9c..4ee969d 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
kvm_vcpu *vcpu,
  
  	switch (get_op(inst)) {

case 0:
-   emulated = EMULATE_FAIL;
if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
(inst == swab32(inst_sc))) {
/*
@@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
kvm_vcpu *vcpu,
kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
emulated = EMULATE_DONE;
+   } else {
+   kvmppc_core_queue_program(vcpu, SRR1_PROGILL);


But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it 
up in book3s_emulate.c is definitely the wrong spot.


So what is the problem you're trying to solve? Is the SRR0 at the wrong 
spot or are the log messages the problem?



Alex

Re: [PATCH] kvm-pr: manage illegal instructions

[Alexander Graf]

On 03/15/2016 09:18 PM, Laurent Vivier wrote:

While writing some instruction tests for kvm-unit-tests for powerpc,
I've found that illegal instructions are not managed correctly with kvm-pr,
while it is fine with kvm-hv.

When an illegal instruction (like ".long 0") is processed by kvm-pr,
the kernel logs are filled with:

  Couldn't emulate instruction 0x (op 0 xop 0)
  kvmppc_handle_exit_pr: emulation at 700 failed ()

While the exception handler receives an interrupt for each instruction
executed after the illegal instruction.

Signed-off-by: Laurent Vivier 
---
  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
  1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_emulate.c 
b/arch/powerpc/kvm/book3s_emulate.c
index 2afdb9c..4ee969d 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
kvm_vcpu *vcpu,
  
  	switch (get_op(inst)) {

case 0:
-   emulated = EMULATE_FAIL;
if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
(inst == swab32(inst_sc))) {
/*
@@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
kvm_vcpu *vcpu,
kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
emulated = EMULATE_DONE;
+   } else {
+   kvmppc_core_queue_program(vcpu, SRR1_PROGILL);


But isn't that exactly what the semantic of EMULATE_FAIL is? Fixing it 
up in book3s_emulate.c is definitely the wrong spot.


So what is the problem you're trying to solve? Is the SRR0 at the wrong 
spot or are the log messages the problem?



Alex

Re: [PATCH] kvm-pr: manage illegal instructions

[Paolo Bonzini]

On 09/05/2016 10:14, Thomas Huth wrote:
>> > Tested-by: Thomas Huth 
> Ping!
> 
> Alex, Paul, could you please pick up this patch? This patch is required
> to get the kvm-unit-tests working properly with kvm-pr, so I'd be glad
> if we could get this included finally...

I have a pull request for 4.6 final to send tomorrow; do you want me to
include it?

Thanks,

Paolo

Re: [PATCH] kvm-pr: manage illegal instructions

[Paolo Bonzini]

On 09/05/2016 10:14, Thomas Huth wrote:
>> > Tested-by: Thomas Huth 
> Ping!
> 
> Alex, Paul, could you please pick up this patch? This patch is required
> to get the kvm-unit-tests working properly with kvm-pr, so I'd be glad
> if we could get this included finally...

I have a pull request for 4.6 final to send tomorrow; do you want me to
include it?

Thanks,

Paolo

Re: [PATCH] kvm-pr: manage illegal instructions

[Thomas Huth]

On 21.04.2016 11:25, Thomas Huth wrote:
> On 15.03.2016 21:18, Laurent Vivier wrote:
>> While writing some instruction tests for kvm-unit-tests for powerpc,
>> I've found that illegal instructions are not managed correctly with kvm-pr,
>> while it is fine with kvm-hv.
>>
>> When an illegal instruction (like ".long 0") is processed by kvm-pr,
>> the kernel logs are filled with:
>>
>>  Couldn't emulate instruction 0x (op 0 xop 0)
>>  kvmppc_handle_exit_pr: emulation at 700 failed ()
>>
>> While the exception handler receives an interrupt for each instruction
>> executed after the illegal instruction.
>>
>> Signed-off-by: Laurent Vivier 
>> ---
>>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kvm/book3s_emulate.c 
>> b/arch/powerpc/kvm/book3s_emulate.c
>> index 2afdb9c..4ee969d 100644
>> --- a/arch/powerpc/kvm/book3s_emulate.c
>> +++ b/arch/powerpc/kvm/book3s_emulate.c
>> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
>> kvm_vcpu *vcpu,
>>  
>>  switch (get_op(inst)) {
>>  case 0:
>> -emulated = EMULATE_FAIL;
>>  if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>>  (inst == swab32(inst_sc))) {
>>  /*
>> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, 
>> struct kvm_vcpu *vcpu,
>>  kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>>  kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>>  emulated = EMULATE_DONE;
>> +} else {
>> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>> +emulated = EMULATE_AGAIN;
>>  }
>>  break;
>>  case 19:
>>
> 
> Tested-by: Thomas Huth 

Ping!

Alex, Paul, could you please pick up this patch? This patch is required
to get the kvm-unit-tests working properly with kvm-pr, so I'd be glad
if we could get this included finally...

Thanks,
 Thomas

Re: [PATCH] kvm-pr: manage illegal instructions

[Thomas Huth]

On 21.04.2016 11:25, Thomas Huth wrote:
> On 15.03.2016 21:18, Laurent Vivier wrote:
>> While writing some instruction tests for kvm-unit-tests for powerpc,
>> I've found that illegal instructions are not managed correctly with kvm-pr,
>> while it is fine with kvm-hv.
>>
>> When an illegal instruction (like ".long 0") is processed by kvm-pr,
>> the kernel logs are filled with:
>>
>>  Couldn't emulate instruction 0x (op 0 xop 0)
>>  kvmppc_handle_exit_pr: emulation at 700 failed ()
>>
>> While the exception handler receives an interrupt for each instruction
>> executed after the illegal instruction.
>>
>> Signed-off-by: Laurent Vivier 
>> ---
>>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kvm/book3s_emulate.c 
>> b/arch/powerpc/kvm/book3s_emulate.c
>> index 2afdb9c..4ee969d 100644
>> --- a/arch/powerpc/kvm/book3s_emulate.c
>> +++ b/arch/powerpc/kvm/book3s_emulate.c
>> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
>> kvm_vcpu *vcpu,
>>  
>>  switch (get_op(inst)) {
>>  case 0:
>> -emulated = EMULATE_FAIL;
>>  if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>>  (inst == swab32(inst_sc))) {
>>  /*
>> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, 
>> struct kvm_vcpu *vcpu,
>>  kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>>  kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>>  emulated = EMULATE_DONE;
>> +} else {
>> +kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
>> +emulated = EMULATE_AGAIN;
>>  }
>>  break;
>>  case 19:
>>
> 
> Tested-by: Thomas Huth 

Ping!

Alex, Paul, could you please pick up this patch? This patch is required
to get the kvm-unit-tests working properly with kvm-pr, so I'd be glad
if we could get this included finally...

Thanks,
 Thomas

Re: [PATCH] kvm-pr: manage illegal instructions

[Thomas Huth]

On 15.03.2016 21:18, Laurent Vivier wrote:
> While writing some instruction tests for kvm-unit-tests for powerpc,
> I've found that illegal instructions are not managed correctly with kvm-pr,
> while it is fine with kvm-hv.
> 
> When an illegal instruction (like ".long 0") is processed by kvm-pr,
> the kernel logs are filled with:
> 
>  Couldn't emulate instruction 0x (op 0 xop 0)
>  kvmppc_handle_exit_pr: emulation at 700 failed ()
> 
> While the exception handler receives an interrupt for each instruction
> executed after the illegal instruction.
> 
> Signed-off-by: Laurent Vivier 
> ---
>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_emulate.c 
> b/arch/powerpc/kvm/book3s_emulate.c
> index 2afdb9c..4ee969d 100644
> --- a/arch/powerpc/kvm/book3s_emulate.c
> +++ b/arch/powerpc/kvm/book3s_emulate.c
> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
> kvm_vcpu *vcpu,
>  
>   switch (get_op(inst)) {
>   case 0:
> - emulated = EMULATE_FAIL;
>   if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>   (inst == swab32(inst_sc))) {
>   /*
> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
> kvm_vcpu *vcpu,
>   kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>   kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>   emulated = EMULATE_DONE;
> + } else {
> + kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> + emulated = EMULATE_AGAIN;
>   }
>   break;
>   case 19:
> 

Tested-by: Thomas Huth 

Re: [PATCH] kvm-pr: manage illegal instructions

[Thomas Huth]

On 15.03.2016 21:18, Laurent Vivier wrote:
> While writing some instruction tests for kvm-unit-tests for powerpc,
> I've found that illegal instructions are not managed correctly with kvm-pr,
> while it is fine with kvm-hv.
> 
> When an illegal instruction (like ".long 0") is processed by kvm-pr,
> the kernel logs are filled with:
> 
>  Couldn't emulate instruction 0x (op 0 xop 0)
>  kvmppc_handle_exit_pr: emulation at 700 failed ()
> 
> While the exception handler receives an interrupt for each instruction
> executed after the illegal instruction.
> 
> Signed-off-by: Laurent Vivier 
> ---
>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_emulate.c 
> b/arch/powerpc/kvm/book3s_emulate.c
> index 2afdb9c..4ee969d 100644
> --- a/arch/powerpc/kvm/book3s_emulate.c
> +++ b/arch/powerpc/kvm/book3s_emulate.c
> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
> kvm_vcpu *vcpu,
>  
>   switch (get_op(inst)) {
>   case 0:
> - emulated = EMULATE_FAIL;
>   if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>   (inst == swab32(inst_sc))) {
>   /*
> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
> kvm_vcpu *vcpu,
>   kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>   kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>   emulated = EMULATE_DONE;
> + } else {
> + kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> + emulated = EMULATE_AGAIN;
>   }
>   break;
>   case 19:
> 

Tested-by: Thomas Huth 

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

Ping?

On 15/03/2016 21:18, Laurent Vivier wrote:
> While writing some instruction tests for kvm-unit-tests for powerpc,
> I've found that illegal instructions are not managed correctly with kvm-pr,
> while it is fine with kvm-hv.
> 
> When an illegal instruction (like ".long 0") is processed by kvm-pr,
> the kernel logs are filled with:
> 
>  Couldn't emulate instruction 0x (op 0 xop 0)
>  kvmppc_handle_exit_pr: emulation at 700 failed ()
> 
> While the exception handler receives an interrupt for each instruction
> executed after the illegal instruction.
> 
> Signed-off-by: Laurent Vivier 
> ---
>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_emulate.c 
> b/arch/powerpc/kvm/book3s_emulate.c
> index 2afdb9c..4ee969d 100644
> --- a/arch/powerpc/kvm/book3s_emulate.c
> +++ b/arch/powerpc/kvm/book3s_emulate.c
> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
> kvm_vcpu *vcpu,
>  
>   switch (get_op(inst)) {
>   case 0:
> - emulated = EMULATE_FAIL;
>   if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>   (inst == swab32(inst_sc))) {
>   /*
> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
> kvm_vcpu *vcpu,
>   kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>   kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>   emulated = EMULATE_DONE;
> + } else {
> + kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> + emulated = EMULATE_AGAIN;
>   }
>   break;
>   case 19:
> 

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

Ping?

On 15/03/2016 21:18, Laurent Vivier wrote:
> While writing some instruction tests for kvm-unit-tests for powerpc,
> I've found that illegal instructions are not managed correctly with kvm-pr,
> while it is fine with kvm-hv.
> 
> When an illegal instruction (like ".long 0") is processed by kvm-pr,
> the kernel logs are filled with:
> 
>  Couldn't emulate instruction 0x (op 0 xop 0)
>  kvmppc_handle_exit_pr: emulation at 700 failed ()
> 
> While the exception handler receives an interrupt for each instruction
> executed after the illegal instruction.
> 
> Signed-off-by: Laurent Vivier 
> ---
>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_emulate.c 
> b/arch/powerpc/kvm/book3s_emulate.c
> index 2afdb9c..4ee969d 100644
> --- a/arch/powerpc/kvm/book3s_emulate.c
> +++ b/arch/powerpc/kvm/book3s_emulate.c
> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
> kvm_vcpu *vcpu,
>  
>   switch (get_op(inst)) {
>   case 0:
> - emulated = EMULATE_FAIL;
>   if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>   (inst == swab32(inst_sc))) {
>   /*
> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
> kvm_vcpu *vcpu,
>   kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>   kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>   emulated = EMULATE_DONE;
> + } else {
> + kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> + emulated = EMULATE_AGAIN;
>   }
>   break;
>   case 19:
> 

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

Hi,

as Paolo has merged the test into kvm-unit-tests, this patch (and
original bug) can be now tested with it.

git://git.kernel.org/pub/scm/virt/kvm/kvm-unit-tests.git

at least:

be9b007 powerpc: add test to check invalid instruction trap

Run this with KVM-PR and check your dmesg:

qemu-system-ppc64 -machine pseries,accel=kvm \
  -bios powerpc/boot_rom.bin \
  -display none -serial stdio \
  -kernel powerpc/emulator.elf -smp 1

Laurent

On 15/03/2016 21:18, Laurent Vivier wrote:
> While writing some instruction tests for kvm-unit-tests for powerpc,
> I've found that illegal instructions are not managed correctly with kvm-pr,
> while it is fine with kvm-hv.
> 
> When an illegal instruction (like ".long 0") is processed by kvm-pr,
> the kernel logs are filled with:
> 
>  Couldn't emulate instruction 0x (op 0 xop 0)
>  kvmppc_handle_exit_pr: emulation at 700 failed ()
> 
> While the exception handler receives an interrupt for each instruction
> executed after the illegal instruction.
> 
> Signed-off-by: Laurent Vivier 
> ---
>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_emulate.c 
> b/arch/powerpc/kvm/book3s_emulate.c
> index 2afdb9c..4ee969d 100644
> --- a/arch/powerpc/kvm/book3s_emulate.c
> +++ b/arch/powerpc/kvm/book3s_emulate.c
> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
> kvm_vcpu *vcpu,
>  
>   switch (get_op(inst)) {
>   case 0:
> - emulated = EMULATE_FAIL;
>   if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>   (inst == swab32(inst_sc))) {
>   /*
> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
> kvm_vcpu *vcpu,
>   kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>   kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>   emulated = EMULATE_DONE;
> + } else {
> + kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> + emulated = EMULATE_AGAIN;
>   }
>   break;
>   case 19:
> 

Re: [PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

Hi,

as Paolo has merged the test into kvm-unit-tests, this patch (and
original bug) can be now tested with it.

git://git.kernel.org/pub/scm/virt/kvm/kvm-unit-tests.git

at least:

be9b007 powerpc: add test to check invalid instruction trap

Run this with KVM-PR and check your dmesg:

qemu-system-ppc64 -machine pseries,accel=kvm \
  -bios powerpc/boot_rom.bin \
  -display none -serial stdio \
  -kernel powerpc/emulator.elf -smp 1

Laurent

On 15/03/2016 21:18, Laurent Vivier wrote:
> While writing some instruction tests for kvm-unit-tests for powerpc,
> I've found that illegal instructions are not managed correctly with kvm-pr,
> while it is fine with kvm-hv.
> 
> When an illegal instruction (like ".long 0") is processed by kvm-pr,
> the kernel logs are filled with:
> 
>  Couldn't emulate instruction 0x (op 0 xop 0)
>  kvmppc_handle_exit_pr: emulation at 700 failed ()
> 
> While the exception handler receives an interrupt for each instruction
> executed after the illegal instruction.
> 
> Signed-off-by: Laurent Vivier 
> ---
>  arch/powerpc/kvm/book3s_emulate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_emulate.c 
> b/arch/powerpc/kvm/book3s_emulate.c
> index 2afdb9c..4ee969d 100644
> --- a/arch/powerpc/kvm/book3s_emulate.c
> +++ b/arch/powerpc/kvm/book3s_emulate.c
> @@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
> kvm_vcpu *vcpu,
>  
>   switch (get_op(inst)) {
>   case 0:
> - emulated = EMULATE_FAIL;
>   if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
>   (inst == swab32(inst_sc))) {
>   /*
> @@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
> kvm_vcpu *vcpu,
>   kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
>   kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
>   emulated = EMULATE_DONE;
> + } else {
> + kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
> + emulated = EMULATE_AGAIN;
>   }
>   break;
>   case 19:
> 

[PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

While writing some instruction tests for kvm-unit-tests for powerpc,
I've found that illegal instructions are not managed correctly with kvm-pr,
while it is fine with kvm-hv.

When an illegal instruction (like ".long 0") is processed by kvm-pr,
the kernel logs are filled with:

 Couldn't emulate instruction 0x (op 0 xop 0)
 kvmppc_handle_exit_pr: emulation at 700 failed ()

While the exception handler receives an interrupt for each instruction
executed after the illegal instruction.

Signed-off-by: Laurent Vivier 
---
 arch/powerpc/kvm/book3s_emulate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_emulate.c 
b/arch/powerpc/kvm/book3s_emulate.c
index 2afdb9c..4ee969d 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
kvm_vcpu *vcpu,
 
switch (get_op(inst)) {
case 0:
-   emulated = EMULATE_FAIL;
if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
(inst == swab32(inst_sc))) {
/*
@@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
kvm_vcpu *vcpu,
kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
emulated = EMULATE_DONE;
+   } else {
+   kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
+   emulated = EMULATE_AGAIN;
}
break;
case 19:
-- 
2.5.0

[PATCH] kvm-pr: manage illegal instructions

[Laurent Vivier]

While writing some instruction tests for kvm-unit-tests for powerpc,
I've found that illegal instructions are not managed correctly with kvm-pr,
while it is fine with kvm-hv.

When an illegal instruction (like ".long 0") is processed by kvm-pr,
the kernel logs are filled with:

 Couldn't emulate instruction 0x (op 0 xop 0)
 kvmppc_handle_exit_pr: emulation at 700 failed ()

While the exception handler receives an interrupt for each instruction
executed after the illegal instruction.

Signed-off-by: Laurent Vivier 
---
 arch/powerpc/kvm/book3s_emulate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_emulate.c 
b/arch/powerpc/kvm/book3s_emulate.c
index 2afdb9c..4ee969d 100644
--- a/arch/powerpc/kvm/book3s_emulate.c
+++ b/arch/powerpc/kvm/book3s_emulate.c
@@ -99,7 +99,6 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
kvm_vcpu *vcpu,
 
switch (get_op(inst)) {
case 0:
-   emulated = EMULATE_FAIL;
if ((kvmppc_get_msr(vcpu) & MSR_LE) &&
(inst == swab32(inst_sc))) {
/*
@@ -112,6 +111,9 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct 
kvm_vcpu *vcpu,
kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED);
kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4);
emulated = EMULATE_DONE;
+   } else {
+   kvmppc_core_queue_program(vcpu, SRR1_PROGILL);
+   emulated = EMULATE_AGAIN;
}
break;
case 19:
-- 
2.5.0