KVM: VMX: Drop explicit 'nested' check from vmx_set_cr4() (a447e38a) · Commits · 戴 / test

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:

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

Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/vmx.c

+7 −12

Original line number	Diff line number	Diff line
		@@ -3123,18 +3123,13 @@ 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;

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