Commit be916451 authored by Sean Christopherson's avatar Sean Christopherson Committed by Zheng Zengkai
Browse files

KVM: VMX: Drop guest CPUID check for VMXE in vmx_set_cr4() 

stable inclusion
from stable-v5.10.137
commit 8b8b376903b32d3d854f39eeebe018169c920cb6
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60PLB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8b8b376903b32d3d854f39eeebe018169c920cb6



--------------------------------

[ Upstream commit d3a9e414 ]

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: 5e1746d6 ("KVM: nVMX: Allow setting the VMXE bit in CR4")
Reported-by: default avatarStas Sergeev <stsp@users.sourceforge.net>
Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20201007014417.29276-2-sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: default avatarWei Li <liwei391@huawei.com>
parent a5672faa

arch/x86/kvm/vmx/vmx.c

+3 −2
Original line number Diff line number Diff line
@@ -3361,9 +3361,10 @@ 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;

	}