kvm: vmx: Allow guest read access to IA32_TSC

Let the guest read the IA32_TSC MSR with the generic RDMSR instruction
as well as the specific RDTSC(P) instructions. Note that the hardware
applies the TSC multiplier and offset (when applicable) to the result of
RDMSR(IA32_TSC), just as it does to the result of RDTSC(P).

Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d5e81485fc151a136673271dbbf46a52fa6e9191..9b58921f5cd36d049eb613c658724e23c6a04424 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6401,6 +6401,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)
                goto free_msrs;
 
        msr_bitmap = vmx->vmcs01.msr_bitmap;
+       vmx_disable_intercept_for_msr(msr_bitmap, MSR_IA32_TSC, MSR_TYPE_R);
        vmx_disable_intercept_for_msr(msr_bitmap, MSR_FS_BASE, MSR_TYPE_RW);
        vmx_disable_intercept_for_msr(msr_bitmap, MSR_GS_BASE, MSR_TYPE_RW);
        vmx_disable_intercept_for_msr(msr_bitmap, MSR_KERNEL_GS_BASE, MSR_TYPE_RW);