From a943ac50d10aac96dca63d0460365a699d41fdd0 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Tue, 29 May 2018 09:11:32 -0700 Subject: [PATCH] kvm: nVMX: Restrict VMX capability MSR changes Disallow changes to the VMX capability MSRs while the vCPU is in VMX operation. Although this does break the existing API, it helps to avoid some potentially tricky situations for which there is no architected behavior. Signed-off-by: Jim Mattson Reviewed-by: Krish Sadhukhan Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index aff0f3ee6a1d..55f86eebc780 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -3538,6 +3538,13 @@ static int vmx_set_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data) { struct vcpu_vmx *vmx = to_vmx(vcpu); + /* + * Don't allow changes to the VMX capability MSRs while the vCPU + * is in VMX operation. + */ + if (vmx->nested.vmxon) + return -EBUSY; + switch (msr_index) { case MSR_IA32_VMX_BASIC: return vmx_restore_vmx_basic(vmx, data);