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

[Alexey Kardashevskiy <aik@ozlabs.ru>]

Paolo, ping?


On 06/12/2022 15:39, Alexey Kardashevskiy wrote:
> 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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