Commit 546e8398 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: nVMX: WARN if subtly-impossible VMFUNC conditions occur 



WARN and inject #UD when emulating VMFUNC for L2 if the function is
out-of-bounds or if VMFUNC is not enabled in vmcs12.  Neither condition
should occur in practice, as the CPU is supposed to prioritize the #UD
over VM-Exit for out-of-bounds input and KVM is supposed to enable
VMFUNC in vmcs02 if and only if it's enabled in vmcs12, but neither of
those dependencies is obvious.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20210609234235.1244004-15-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent c9060662

arch/x86/kvm/vmx/nested.c

+10 −0
Original line number Diff line number Diff line
@@ -5552,6 +5552,16 @@ static int handle_vmfunc(struct kvm_vcpu *vcpu) 
	}



	vmcs12 = get_vmcs12(vcpu);



	/*

	 * #UD on out-of-bounds function has priority over VM-Exit, and VMFUNC

	 * is enabled in vmcs02 if and only if it's enabled in vmcs12.

	 */

	if (WARN_ON_ONCE((function > 63) || !nested_cpu_has_vmfunc(vmcs12))) {

		kvm_queue_exception(vcpu, UD_VECTOR);

		return 1;

	}



	if (!(vmcs12->vm_function_control & BIT_ULL(function)))

		goto fail;