On 10.12.2012, at 11:09, Cornelia Huck wrote:
> On Mon, 10 Dec 2012 08:33:10 +0100
> Alexander Graf <ag...@suse.de> wrote:
>
>>
>> On 07.12.2012, at 13:30, Cornelia Huck wrote:
>>
>>> Add support for handling I/O interrupts (standard, subchannel-related
>>> ones and rudimentary adapter interrupts).
>>>
>>> The subchannel-identifying parameters are encoded into the interrupt
>>> type.
>>>
>>> I/O interrupts are floating, so they can't be injected on a specific
>>> vcpu.
>>>
>>> Reviewed-by: Marcelo Tosatti <mtosa...@redhat.com>
>>> Signed-off-by: Cornelia Huck <cornelia.h...@de.ibm.com>
>>> ---
>>> Documentation/virtual/kvm/api.txt | 4 ++
>>> arch/s390/include/asm/kvm_host.h | 2 +
>>> arch/s390/kvm/interrupt.c | 115
>>> ++++++++++++++++++++++++++++++++++++--
>>> include/uapi/linux/kvm.h | 6 ++
>>> 4 files changed, 122 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/Documentation/virtual/kvm/api.txt
>>> b/Documentation/virtual/kvm/api.txt
>>> index 6671fdc..e298a72 100644
>>> --- a/Documentation/virtual/kvm/api.txt
>>> +++ b/Documentation/virtual/kvm/api.txt
>>> @@ -2068,6 +2068,10 @@ KVM_S390_INT_VIRTIO (vm) - virtio external
>>> interrupt; external interrupt
>>> KVM_S390_INT_SERVICE (vm) - sclp external interrupt; sclp parameter in parm
>>> KVM_S390_INT_EMERGENCY (vcpu) - sigp emergency; source cpu in parm
>>> KVM_S390_INT_EXTERNAL_CALL (vcpu) - sigp external call; source cpu in parm
>>> +KVM_S390_INT_IO(ai,cssid,ssid,schid) (vm) - compound value to indicate an
>>> + I/O interrupt (ai - adapter interrupt; cssid,ssid,schid - subchannel);
>>> + I/O interruption parameters in parm (subchannel) and parm64 (intparm,
>>> + interruption subclass)
>>>
>>> Note that the vcpu ioctl is asynchronous to vcpu execution.
>>>
>>> diff --git a/arch/s390/include/asm/kvm_host.h
>>> b/arch/s390/include/asm/kvm_host.h
>>> index b784154..e47f697 100644
>>> --- a/arch/s390/include/asm/kvm_host.h
>>> +++ b/arch/s390/include/asm/kvm_host.h
>>> @@ -76,6 +76,7 @@ struct kvm_s390_sie_block {
>>> __u64 epoch; /* 0x0038 */
>>> __u8 reserved40[4]; /* 0x0040 */
>>> #define LCTL_CR0 0x8000
>>> +#define LCTL_CR6 0x0200
>>> __u16 lctl; /* 0x0044 */
>>> __s16 icpua; /* 0x0046 */
>>> __u32 ictl; /* 0x0048 */
>>> @@ -127,6 +128,7 @@ struct kvm_vcpu_stat {
>>> u32 deliver_prefix_signal;
>>> u32 deliver_restart_signal;
>>> u32 deliver_program_int;
>>> + u32 deliver_io_int;
>>> u32 exit_wait_state;
>>> u32 instruction_stidp;
>>> u32 instruction_spx;
>>> diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
>>> index c30615e..070ba22 100644
>>> --- a/arch/s390/kvm/interrupt.c
>>> +++ b/arch/s390/kvm/interrupt.c
>>> @@ -21,11 +21,26 @@
>>> #include "gaccess.h"
>>> #include "trace-s390.h"
>>>
>>> +#define IOINT_SCHID_MASK 0x0000ffff
>>> +#define IOINT_SSID_MASK 0x00030000
>>> +#define IOINT_CSSID_MASK 0x03fc0000
>>> +#define IOINT_AI_MASK 0x04000000
>>> +
>>> +static int is_ioint(u64 type)
>>> +{
>>> + return ((type & 0xfffe0000u) != 0xfffe0000u);
>>> +}
>>> +
>>> static int psw_extint_disabled(struct kvm_vcpu *vcpu)
>>> {
>>> return !(vcpu->arch.sie_block->gpsw.mask & PSW_MASK_EXT);
>>> }
>>>
>>> +static int psw_ioint_disabled(struct kvm_vcpu *vcpu)
>>> +{
>>> + return !(vcpu->arch.sie_block->gpsw.mask & PSW_MASK_IO);
>>> +}
>>> +
>>> static int psw_interrupts_disabled(struct kvm_vcpu *vcpu)
>>> {
>>> if ((vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PER) ||
>>> @@ -68,7 +83,18 @@ static int __interrupt_is_deliverable(struct kvm_vcpu
>>> *vcpu,
>>> case KVM_S390_RESTART:
>>> return 1;
>>> default:
>>> - BUG();
>>> + if (is_ioint(inti->type)) {
>>
>> Though I usually like if (...) { positive) } else { abort(); } coding style
>> in general, it makes code quite hard to read when you are limited to 80
>> characters per line :)
>>
>> I think it'd really help readability if you instead would write
>>
>> if (!is_ioint(...)) {
>> BUG();
>> }
>>
>> and then continue without indent. That problem gets even more obvious
>> further down the file.
>
> Hm, "bad state last" seems to parse, though.
Fine with me. Extract the io bits into a separate function then :). Or maybe
better even just use gcc switch magic:
case 0x0 ... 0xfffdffff:
Alex
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