[Qemu-devel] [PATCH] target-i386: do not read/write MSR_TSC_AUX from KVM if CPUID bit is not set

[Paolo Bonzini <pbonzini@redhat.com>]

KVM does not let you read or write this MSR if the corresponding CPUID
bit is not set.  This in turn causes MSRs that come after MSR_TSC_AUX
to be ignored by KVM_SET_MRSS.

One visible symptom is that s3.flat from kvm-unit-tests fails with
CPUs that do not have RDTSCP, because the SMBASE is not reset to
0x30000 after reset.

Fixes: c9b8f6b6210847b4381c5b2ee172b1c7eb9985d6
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target-i386/kvm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 87ab969..19e2d94 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -917,6 +917,9 @@ int kvm_arch_init_vcpu(CPUState *cs)
     if (env->features[FEAT_1_EDX] & CPUID_MTRR) {
         has_msr_mtrr = true;
     }
+    if (!(env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP)) {
+        has_msr_tsc_aux = false;
+    }
 
     return 0;
 }
-- 
2.5.5