From: Paolo Bonzini <pbonzini@redhat.com>
Date: Wed, 1 Jun 2022 07:21:19 +0000 (-0400)
Subject: KVM: vmx, pmu: accept 0 for host-initiated write to MSR_IA32_DS_AREA
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=bfb088d9fb5abdd3fbf00bae9abdfee8b92265aa;p=linux.git

KVM: vmx, pmu: accept 0 for host-initiated write to MSR_IA32_DS_AREA

Whenever an MSR is part of KVM_GET_MSR_INDEX_LIST, as is the case
for MSR_IA32_DS_AREA, it has to be always settable with KVM_SET_MSR.
Accept a zero value for these MSRs to obey the contract.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 2fc90080dcce0..5bc7cfc753fc1 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -443,6 +443,8 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		}
 		break;
 	case MSR_IA32_DS_AREA:
+		if (msr_info->host_initiated && data && !guest_cpuid_has(vcpu, X86_FEATURE_DS))
+			return 1;
 		if (is_noncanonical_address(data, vcpu))
 			return 1;
 		pmu->ds_area = data;