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

[Alexey Kardashevskiy]

Sean, can you help please with this? Thanks,


On 28/02/2023 17:17, Alexey Kardashevskiy wrote:
> Anyone, ping?
> 
> On 02/01/2023 11:43, Alexey Kardashevskiy wrote:
>> 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 at ozlabs.ru>
>>>>> Acked-by: Nicholas Piggin <npiggin at gmail.com>
>>>>> Acked-by: Marc Zyngier <maz at 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