diff mbox series

[05/30] KVM: x86: hyper-v: Honor HV_MSR_HYPERCALL_AVAILABLE privilege bit

Message ID 20210419160127.192712-6-vkuznets@redhat.com (mailing list archive)
State New
Headers show
Series KVM: x86: hyper-v: Fine-grained access check to Hyper-V hypercalls and MSRs | expand

Commit Message

Vitaly Kuznetsov April 19, 2021, 4:01 p.m. UTC
HV_X64_MSR_GUEST_OS_ID/HV_X64_MSR_HYPERCALL are only available to guest
when HV_MSR_HYPERCALL_AVAILABLE bit is exposed.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 arch/x86/kvm/hyperv.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)
diff mbox series

Patch

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index b5bc16ea2595..13011803ebbd 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1196,6 +1196,18 @@  void kvm_hv_invalidate_tsc_page(struct kvm *kvm)
 
 static bool hv_check_msr_access(struct kvm_vcpu_hv *hv_vcpu, u32 msr)
 {
+	if (!hv_vcpu->enforce_cpuid)
+		return true;
+
+	switch (msr) {
+	case HV_X64_MSR_GUEST_OS_ID:
+	case HV_X64_MSR_HYPERCALL:
+		return hv_vcpu->cpuid_cache.features_eax &
+			HV_MSR_HYPERCALL_AVAILABLE;
+	default:
+		break;
+	}
+
 	return true;
 }