On Wed, Jun 30, 2021 at 2:48 PM David Matlack <dmatlack@xxxxxxxxxx> wrote:
>
> Enum values have to be exported to userspace since the formatting is not
> done in the kernel. Without doing this perf maps RET_PF_FIXED and
> RET_PF_SPURIOUS to 0, which results in incorrect output:
>
> $ perf record -a -e kvmmmu:fast_page_fault --filter "ret==3" -- ./access_tracking_perf_test
> $ perf script | head -1
> [...] new 610006048d25877 spurious 0 fixed 0 <------ should be 1
>
> Fix this by exporting the enum values to userspace with TRACE_DEFINE_ENUM.
>
> Fixes: c4371c2a682e ("KVM: x86/mmu: Return unique RET_PF_* values if the fault was fixed")
> Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu/mmutrace.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kvm/mmu/mmutrace.h b/arch/x86/kvm/mmu/mmutrace.h
> index efbad33a0645..55c7e0fcda52 100644
> --- a/arch/x86/kvm/mmu/mmutrace.h
> +++ b/arch/x86/kvm/mmu/mmutrace.h
> @@ -244,6 +244,9 @@ TRACE_EVENT(
> __entry->access)
> );
>
> +TRACE_DEFINE_ENUM(RET_PF_FIXED);
> +TRACE_DEFINE_ENUM(RET_PF_SPURIOUS);
> +
If you're planning to send out a v3 anyway, it might be worth adding
all the PF return code enums:
enum {
RET_PF_RETRY = 0,
RET_PF_EMULATE,
RET_PF_INVALID,
RET_PF_FIXED,
RET_PF_SPURIOUS,
};
Just so that no one has to worry about this in the future.
> TRACE_EVENT(
> fast_page_fault,
> TP_PROTO(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u32 error_code,
> --
> 2.32.0.93.g670b81a890-goog
>
