Messages in this thread Patch in this message | | | From | Sean Christopherson <> | Subject | [PATCH 1/6] KVM: VMX: Drop guest CPUID check for VMXE in vmx_set_cr4() | Date | Tue, 6 Oct 2020 18:44:12 -0700 |
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Drop vmx_set_cr4()'s somewhat hidden guest_cpuid_has() check on VMXE now that common x86 handles the check by incorporating VMXE into the CR4 reserved bits, i.e. in cr4_guest_rsvd_bits. This fixes a bug where KVM incorrectly rejects KVM_SET_SREGS with CR4.VMXE=1 if it's executed before KVM_SET_CPUID{,2}.
Fixes: 5e1746d6205d ("KVM: nVMX: Allow setting the VMXE bit in CR4") Reported-by: Stas Sergeev <stsp@users.sourceforge.net> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> --- arch/x86/kvm/vmx/vmx.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index e23c41ccfac9..99ea57ba2a84 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3110,9 +3110,10 @@ int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) * must first be able to turn on cr4.VMXE (see handle_vmon()). * So basically the check on whether to allow nested VMX * is here. We operate under the default treatment of SMM, - * so VMX cannot be enabled under SMM. + * so VMX cannot be enabled under SMM. Note, guest CPUID is + * intentionally ignored, it's handled by cr4_guest_rsvd_bits. */ - if (!nested_vmx_allowed(vcpu) || is_smm(vcpu)) + if (!nested || is_smm(vcpu)) return 1; } -- 2.28.0
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