On Tue, Jan 18, 2022 at 04:11:07AM -0500, Paolo Bonzini wrote:
> From: Wei Wang <wei.w.wang@xxxxxxxxx>
>
> [ upstream commit 9fb12fe5b93b94b9e607509ba461e17f4cc6a264 ]
>
> The fixed counter 3 is used for the Topdown metrics, which hasn't been
> enabled for KVM guests. Userspace accessing to it will fail as it's not
> included in get_fixed_pmc(). This breaks KVM selftests on ICX+ machines,
> which have this counter.
>
> To reproduce it on ICX+ machines, ./state_test reports:
> ==== Test Assertion Failure ====
> lib/x86_64/processor.c:1078: r == nmsrs
> pid=4564 tid=4564 - Argument list too long
> 1 0x000000000040b1b9: vcpu_save_state at processor.c:1077
> 2 0x0000000000402478: main at state_test.c:209 (discriminator 6)
> 3 0x00007fbe21ed5f92: ?? ??:0
> 4 0x000000000040264d: _start at ??:?
> Unexpected result from KVM_GET_MSRS, r: 17 (failed MSR was 0x30c)
>
> With this patch, it works well.
>
> Signed-off-by: Wei Wang <wei.w.wang@xxxxxxxxx>
> Message-Id: <20211217124934.32893-1-wei.w.wang@xxxxxxxxx>
> Fixes: e2ada66ec418 ("kvm: x86: Add Intel PMU MSRs to msrs_to_save[]")
> Cc: stable@xxxxxxxxxxxxxxx # 5.4.x
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> arch/x86/kvm/x86.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 9a2972fdae82..d490b83d640c 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1331,7 +1331,7 @@ static const u32 msrs_to_save_all[] = {
> MSR_IA32_UMWAIT_CONTROL,
>
> MSR_ARCH_PERFMON_FIXED_CTR0, MSR_ARCH_PERFMON_FIXED_CTR1,
> - MSR_ARCH_PERFMON_FIXED_CTR0 + 2, MSR_ARCH_PERFMON_FIXED_CTR0 + 3,
> + MSR_ARCH_PERFMON_FIXED_CTR0 + 2,
> MSR_CORE_PERF_FIXED_CTR_CTRL, MSR_CORE_PERF_GLOBAL_STATUS,
> MSR_CORE_PERF_GLOBAL_CTRL, MSR_CORE_PERF_GLOBAL_OVF_CTRL,
> MSR_ARCH_PERFMON_PERFCTR0, MSR_ARCH_PERFMON_PERFCTR1,
> --
> 2.31.1
>
Now queued up, thanks.
greg k-h
