Commit 26296e1c authored by Sean Christopherson's avatar Sean Christopherson Committed by Zheng Zengkai
Browse files

KVM: VMX: Drop explicit 'nested' check from vmx_set_cr4() 

stable inclusion
from stable-v5.10.137
commit da7f731f2ed5b4a082567967ce74be274aab2daf
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=da7f731f2ed5b4a082567967ce74be274aab2daf



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

[ Upstream commit a447e38a ]

Drop vmx_set_cr4()'s explicit check on the 'nested' module param now
that common x86 handles the check by incorporating VMXE into the CR4
reserved bits, via kvm_cpu_caps.  X86_FEATURE_VMX is set in kvm_cpu_caps
(by vmx_set_cpu_caps()), if and only if 'nested' is true.

No functional change intended.

Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20201007014417.29276-3-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 be916451

arch/x86/kvm/vmx/vmx.c

+7 −12
Original line number Diff line number Diff line
@@ -3355,18 +3355,13 @@ int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4) 
		}

	}



	if (cr4 & X86_CR4_VMXE) {

	/*

		 * To use VMXON (and later other VMX instructions), a guest

		 * 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.  Note, guest CPUID is

		 * intentionally ignored, it's handled by cr4_guest_rsvd_bits.

	 * We operate under the default treatment of SMM, so VMX cannot be

	 * enabled under SMM.  Note, whether or not VMXE is allowed at all is

	 * handled by kvm_valid_cr4().

	 */

		if (!nested || is_smm(vcpu))

	if ((cr4 & X86_CR4_VMXE) && is_smm(vcpu))

		return 1;

	}



	if (vmx->nested.vmxon && !nested_cr4_valid(vcpu, cr4))

		return 1;