Re: [PATCH] KVM: x86: don't notify userspace IOAPIC on edge EOI

[Paolo Bonzini]

On 08/10/2015 20:34, Radim Krčmář wrote:
> 2015-10-08 20:30+0200, Radim Krčmář:
>> On real hardware, edge-triggered interrupts don't set a bit in TMR,
>> which means that IOAPIC isn't notified on EOI.  Do the same here.
>>
>> Staying in guest/kernel mode after edge EOI is what we want for most
>> devices.  If some bugs could be nicely worked around with edge EOI
>> notifications, we should invest in a better interface.
>>
>> Signed-off-by: Radim Krčmář 
>> ---
>>  Completely untested.
>>  
>> diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
>> @@ -389,13 +389,15 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 
>> *eoi_exit_bitmap)
>>  for (i = 0; i < nr_ioapic_pins; ++i) {
>>  hlist_for_each_entry(entry, >map[i], link) {
>>  u32 dest_id, dest_mode;
>> +bool level;
>>  
>>  if (entry->type != KVM_IRQ_ROUTING_MSI)
>>  continue;
>>  dest_id = (entry->msi.address_lo >> 12) & 0xff;
>>  dest_mode = (entry->msi.address_lo >> 2) & 0x1;
>> -if (kvm_apic_match_dest(vcpu, NULL, 0, dest_id,
>> -dest_mode)) {
>> +level = entry->msi.data & MSI_DATA_TRIGGER_LEVEL;
>> +if (level && kvm_apic_match_dest(vcpu, NULL, 0,
> 
> Describing that result is an overkill -- I'll send v2 if the idea is
> accepted.

It's okay and it matches the other lines before.  I'm applying this too,
but I would appreciate Steve's Tested-by before moving it to kvm/next.


Paolo
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Re: [PATCH] KVM: x86: don't notify userspace IOAPIC on edge EOI

[Paolo Bonzini]

On 08/10/2015 20:34, Radim Krčmář wrote:
> 2015-10-08 20:30+0200, Radim Krčmář:
>> On real hardware, edge-triggered interrupts don't set a bit in TMR,
>> which means that IOAPIC isn't notified on EOI.  Do the same here.
>>
>> Staying in guest/kernel mode after edge EOI is what we want for most
>> devices.  If some bugs could be nicely worked around with edge EOI
>> notifications, we should invest in a better interface.
>>
>> Signed-off-by: Radim Krčmář 
>> ---
>>  Completely untested.
>>  
>> diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
>> @@ -389,13 +389,15 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 
>> *eoi_exit_bitmap)
>>  for (i = 0; i < nr_ioapic_pins; ++i) {
>>  hlist_for_each_entry(entry, >map[i], link) {
>>  u32 dest_id, dest_mode;
>> +bool level;
>>  
>>  if (entry->type != KVM_IRQ_ROUTING_MSI)
>>  continue;
>>  dest_id = (entry->msi.address_lo >> 12) & 0xff;
>>  dest_mode = (entry->msi.address_lo >> 2) & 0x1;
>> -if (kvm_apic_match_dest(vcpu, NULL, 0, dest_id,
>> -dest_mode)) {
>> +level = entry->msi.data & MSI_DATA_TRIGGER_LEVEL;
>> +if (level && kvm_apic_match_dest(vcpu, NULL, 0,
> 
> Describing that result is an overkill -- I'll send v2 if the idea is
> accepted.

It's okay and it matches the other lines before.  I'm applying this too,
but I would appreciate Steve's Tested-by before moving it to kvm/next.


Paolo
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Re: [PATCH] KVM: x86: don't notify userspace IOAPIC on edge EOI

[Radim Krčmář]

2015-10-08 20:30+0200, Radim Krčmář:
> On real hardware, edge-triggered interrupts don't set a bit in TMR,
> which means that IOAPIC isn't notified on EOI.  Do the same here.
> 
> Staying in guest/kernel mode after edge EOI is what we want for most
> devices.  If some bugs could be nicely worked around with edge EOI
> notifications, we should invest in a better interface.
> 
> Signed-off-by: Radim Krčmář 
> ---
>  Completely untested.
>  
> diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
> @@ -389,13 +389,15 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 
> *eoi_exit_bitmap)
>   for (i = 0; i < nr_ioapic_pins; ++i) {
>   hlist_for_each_entry(entry, >map[i], link) {
>   u32 dest_id, dest_mode;
> + bool level;
>  
>   if (entry->type != KVM_IRQ_ROUTING_MSI)
>   continue;
>   dest_id = (entry->msi.address_lo >> 12) & 0xff;
>   dest_mode = (entry->msi.address_lo >> 2) & 0x1;
> - if (kvm_apic_match_dest(vcpu, NULL, 0, dest_id,
> - dest_mode)) {
> + level = entry->msi.data & MSI_DATA_TRIGGER_LEVEL;
> + if (level && kvm_apic_match_dest(vcpu, NULL, 0,

Describing that result is an overkill -- I'll send v2 if the idea is
accepted.
--
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the body of a message to majord...@vger.kernel.org
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[PATCH] KVM: x86: don't notify userspace IOAPIC on edge EOI

[Radim Krčmář]

On real hardware, edge-triggered interrupts don't set a bit in TMR,
which means that IOAPIC isn't notified on EOI.  Do the same here.

Staying in guest/kernel mode after edge EOI is what we want for most
devices.  If some bugs could be nicely worked around with edge EOI
notifications, we should invest in a better interface.

Signed-off-by: Radim Krčmář 
---
 Completely untested.
 
 arch/x86/kvm/irq_comm.c | 6 --
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index c89228980230..8f4499c7ffc1 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -389,13 +389,15 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 
*eoi_exit_bitmap)
for (i = 0; i < nr_ioapic_pins; ++i) {
hlist_for_each_entry(entry, >map[i], link) {
u32 dest_id, dest_mode;
+   bool level;
 
if (entry->type != KVM_IRQ_ROUTING_MSI)
continue;
dest_id = (entry->msi.address_lo >> 12) & 0xff;
dest_mode = (entry->msi.address_lo >> 2) & 0x1;
-   if (kvm_apic_match_dest(vcpu, NULL, 0, dest_id,
-   dest_mode)) {
+   level = entry->msi.data & MSI_DATA_TRIGGER_LEVEL;
+   if (level && kvm_apic_match_dest(vcpu, NULL, 0,
+   dest_id, dest_mode)) {
u32 vector = entry->msi.data & 0xff;
 
__set_bit(vector,
-- 
2.5.3

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Re: [PATCH] KVM: x86: don't notify userspace IOAPIC on edge EOI

[Radim Krčmář]

2015-10-08 20:30+0200, Radim Krčmář:
> On real hardware, edge-triggered interrupts don't set a bit in TMR,
> which means that IOAPIC isn't notified on EOI.  Do the same here.
> 
> Staying in guest/kernel mode after edge EOI is what we want for most
> devices.  If some bugs could be nicely worked around with edge EOI
> notifications, we should invest in a better interface.
> 
> Signed-off-by: Radim Krčmář 
> ---
>  Completely untested.
>  
> diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
> @@ -389,13 +389,15 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 
> *eoi_exit_bitmap)
>   for (i = 0; i < nr_ioapic_pins; ++i) {
>   hlist_for_each_entry(entry, >map[i], link) {
>   u32 dest_id, dest_mode;
> + bool level;
>  
>   if (entry->type != KVM_IRQ_ROUTING_MSI)
>   continue;
>   dest_id = (entry->msi.address_lo >> 12) & 0xff;
>   dest_mode = (entry->msi.address_lo >> 2) & 0x1;
> - if (kvm_apic_match_dest(vcpu, NULL, 0, dest_id,
> - dest_mode)) {
> + level = entry->msi.data & MSI_DATA_TRIGGER_LEVEL;
> + if (level && kvm_apic_match_dest(vcpu, NULL, 0,

Describing that result is an overkill -- I'll send v2 if the idea is
accepted.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[PATCH] KVM: x86: don't notify userspace IOAPIC on edge EOI

[Radim Krčmář]

On real hardware, edge-triggered interrupts don't set a bit in TMR,
which means that IOAPIC isn't notified on EOI.  Do the same here.

Staying in guest/kernel mode after edge EOI is what we want for most
devices.  If some bugs could be nicely worked around with edge EOI
notifications, we should invest in a better interface.

Signed-off-by: Radim Krčmář 
---
 Completely untested.
 
 arch/x86/kvm/irq_comm.c | 6 --
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index c89228980230..8f4499c7ffc1 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -389,13 +389,15 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 
*eoi_exit_bitmap)
for (i = 0; i < nr_ioapic_pins; ++i) {
hlist_for_each_entry(entry, >map[i], link) {
u32 dest_id, dest_mode;
+   bool level;
 
if (entry->type != KVM_IRQ_ROUTING_MSI)
continue;
dest_id = (entry->msi.address_lo >> 12) & 0xff;
dest_mode = (entry->msi.address_lo >> 2) & 0x1;
-   if (kvm_apic_match_dest(vcpu, NULL, 0, dest_id,
-   dest_mode)) {
+   level = entry->msi.data & MSI_DATA_TRIGGER_LEVEL;
+   if (level && kvm_apic_match_dest(vcpu, NULL, 0,
+   dest_id, dest_mode)) {
u32 vector = entry->msi.data & 0xff;
 
__set_bit(vector,
-- 
2.5.3

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