[PATCH] KVM: SVM: Set HWCR[TscFreqSel] to host's value

[Shannon Zhao]

KVM sets CPUID.80000007H:EDX[8] to 1, but not set HWCR[TscFreqSel].
This will cause guest kernel printing below log on AMD platform even
though the hardware TSC exactly counts with P0 frequency.
"[Firmware Bug]: TSC doesn't count with P0 frequency!"

Fix it by setting HWCR[TscFreqSel] to host's value to indicate whether
the TSC increments at the P0 frequency.

Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxxxxxxxxx>
---
 arch/x86/kvm/svm/svm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 7e45d03..fb4bb51 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1139,6 +1139,11 @@ static void __svm_vcpu_reset(struct kvm_vcpu *vcpu)
 	svm_init_osvw(vcpu);
 	vcpu->arch.microcode_version = 0x01000065;
 	svm->tsc_ratio_msr = kvm_default_tsc_scaling_ratio;
+	/* 
+	 * TSC frequency select is HWCR[24], set it to host's value to indicate
+	 * whether the TSC increments at the P0 frequency. 
+	 */
+	vcpu->arch.msr_hwcr = native_read_msr(MSR_K7_HWCR) & BIT_ULL(24); 
 
 	if (sev_es_guest(vcpu->kvm))
 		sev_es_vcpu_reset(svm);
-- 
1.8.3.1