[PATCH RFC 15/22] KVM: x86: hyper-v: Honor HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE privilege bit
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: 2021-04-13 12:28:34
Also in:
kvm, lkml
Subsystem:
kernel virtual machine for x86 (kvm/x86), kvm x86 hyper-v (kvm/hyper-v), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Vitaly Kuznetsov, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Synthetic debugging MSRs (HV_X64_MSR_SYNDBG_CONTROL, HV_X64_MSR_SYNDBG_STATUS, HV_X64_MSR_SYNDBG_SEND_BUFFER, HV_X64_MSR_SYNDBG_RECV_BUFFER, HV_X64_MSR_SYNDBG_PENDING_BUFFER, HV_X64_MSR_SYNDBG_OPTIONS) are only available to guest when HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE bit is exposed. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> --- arch/x86/kvm/hyperv.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 0678f1012ed7..1299847c89ba 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c@@ -312,7 +312,9 @@ static int syndbg_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host) { struct kvm_hv_syndbg *syndbg = to_hv_syndbg(vcpu); - if (!kvm_hv_is_syndbg_enabled(vcpu) && !host) + if (unlikely(!host && (!kvm_hv_is_syndbg_enabled(vcpu) || + !(to_hv_vcpu(vcpu)->cpuid_cache.features_edx & + HV_FEATURE_DEBUG_MSRS_AVAILABLE)))) return 1; trace_kvm_hv_syndbg_set_msr(vcpu->vcpu_id,
@@ -351,7 +353,9 @@ static int syndbg_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host) { struct kvm_hv_syndbg *syndbg = to_hv_syndbg(vcpu); - if (!kvm_hv_is_syndbg_enabled(vcpu) && !host) + if (unlikely(!host && (!kvm_hv_is_syndbg_enabled(vcpu) || + !(to_hv_vcpu(vcpu)->cpuid_cache.features_edx & + HV_FEATURE_DEBUG_MSRS_AVAILABLE)))) return 1; switch (msr) {
--
2.30.2