On Tue, Jan 18, 2022 at 04:11:07AM -0500, Paolo Bonzini wrote:

From: Wei Wang wei.w.wang@intel.com

[ 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@intel.com Message-Id: 20211217124934.32893-1-wei.w.wang@intel.com Fixes: e2ada66ec418 ("kvm: x86: Add Intel PMU MSRs to msrs_to_save[]") Cc: stable@vger.kernel.org # 5.4.x Signed-off-by: Paolo Bonzini pbonzini@redhat.com

---

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