Re: [PATCH kernel v4] KVM: PPC: Make KVM_CAP_IRQFD_RESAMPLE support platform dependent

[Alexey Kardashevskiy <aik@ozlabs.ru>]

Paolo, ping? :)


On 27/10/2022 18:38, Alexey Kardashevskiy wrote:
> Paolo, ping?
> 
> 
> On 04/10/2022 10:57, Alexey Kardashevskiy wrote:
>> When introduced, IRQFD resampling worked on POWER8 with XICS. However
>> KVM on POWER9 has never implemented it - the compatibility mode code
>> ("XICS-on-XIVE") misses the kvm_notify_acked_irq() call and the native
>> XIVE mode does not handle INTx in KVM at all.
>>
>> This moved the capability support advertising to platforms and stops
>> advertising it on XIVE, i.e. POWER9 and later.
>>
>> This should cause no behavioural change for other architectures.
>>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>> Acked-by: Nicholas Piggin <npiggin@gmail.com>
>> Acked-by: Marc Zyngier <maz@kernel.org>
>> ---
>> Changes:
>> v4:
>> * removed incorrect clause about changing behavoir on MIPS and RISCV
>>
>> v3:
>> * removed all ifdeferry
>> * removed the capability for MIPS and RISCV
>> * adjusted the commit log about MIPS and RISCV
>>
>> v2:
>> * removed ifdef for ARM64.
>> ---
>>   arch/arm64/kvm/arm.c       | 1 +
>>   arch/powerpc/kvm/powerpc.c | 6 ++++++
>>   arch/s390/kvm/kvm-s390.c   | 1 +
>>   arch/x86/kvm/x86.c         | 1 +
>>   virt/kvm/kvm_main.c        | 1 -
>>   5 files changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
>> index 2ff0ef62abad..d2daa4d375b5 100644
>> --- a/arch/arm64/kvm/arm.c
>> +++ b/arch/arm64/kvm/arm.c
>> @@ -218,6 +218,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, 
>> long ext)
>>       case KVM_CAP_VCPU_ATTRIBUTES:
>>       case KVM_CAP_PTP_KVM:
>>       case KVM_CAP_ARM_SYSTEM_SUSPEND:
>> +    case KVM_CAP_IRQFD_RESAMPLE:
>>           r = 1;
>>           break;
>>       case KVM_CAP_SET_GUEST_DEBUG2:
>> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
>> index fb1490761c87..908ce8bd91c9 100644
>> --- a/arch/powerpc/kvm/powerpc.c
>> +++ b/arch/powerpc/kvm/powerpc.c
>> @@ -593,6 +593,12 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, 
>> long ext)
>>           break;
>>   #endif
>> +#ifdef CONFIG_HAVE_KVM_IRQFD
>> +    case KVM_CAP_IRQFD_RESAMPLE:
>> +        r = !xive_enabled();
>> +        break;
>> +#endif
>> +
>>       case KVM_CAP_PPC_ALLOC_HTAB:
>>           r = hv_enabled;
>>           break;
>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>> index edfd4bbd0cba..7521adadb81b 100644
>> --- a/arch/s390/kvm/kvm-s390.c
>> +++ b/arch/s390/kvm/kvm-s390.c
>> @@ -577,6 +577,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, 
>> long ext)
>>       case KVM_CAP_SET_GUEST_DEBUG:
>>       case KVM_CAP_S390_DIAG318:
>>       case KVM_CAP_S390_MEM_OP_EXTENSION:
>> +    case KVM_CAP_IRQFD_RESAMPLE:
>>           r = 1;
>>           break;
>>       case KVM_CAP_SET_GUEST_DEBUG2:
>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>> index 43a6a7efc6ec..2d6c5a8fdf14 100644
>> --- a/arch/x86/kvm/x86.c
>> +++ b/arch/x86/kvm/x86.c
>> @@ -4395,6 +4395,7 @@ int kvm_vm_ioctl_check_extension(struct kvm 
>> *kvm, long ext)
>>       case KVM_CAP_VAPIC:
>>       case KVM_CAP_ENABLE_CAP:
>>       case KVM_CAP_VM_DISABLE_NX_HUGE_PAGES:
>> +    case KVM_CAP_IRQFD_RESAMPLE:
>>           r = 1;
>>           break;
>>       case KVM_CAP_EXIT_HYPERCALL:
>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>> index 584a5bab3af3..05cf94013f02 100644
>> --- a/virt/kvm/kvm_main.c
>> +++ b/virt/kvm/kvm_main.c
>> @@ -4447,7 +4447,6 @@ static long 
>> kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
>>   #endif
>>   #ifdef CONFIG_HAVE_KVM_IRQFD
>>       case KVM_CAP_IRQFD:
>> -    case KVM_CAP_IRQFD_RESAMPLE:
>>   #endif
>>       case KVM_CAP_IOEVENTFD_ANY_LENGTH:
>>       case KVM_CAP_CHECK_EXTENSION_VM:
> 

-- 
Alexey

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