[PATCH 2/5] KVM: nVMX: Skip VM-Exit Control vmentry checks that are necessary only if VMCS12 is dirty

[Krish Sadhukhan <krish.sadhukhan@oracle.com>]

 ..so that every nested vmentry is not slowed down by those checks.

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
---
 arch/x86/kvm/vmx/nested.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index b0b59c78b3e8..056eba497730 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2505,6 +2505,15 @@ static int nested_check_vm_execution_controls(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
+static int nested_check_vm_exit_controls_full(struct kvm_vcpu *vcpu,
+					      struct vmcs12 *vmcs12)
+{
+	if (nested_vmx_check_exit_msr_switch_controls(vcpu, vmcs12))
+		return -EINVAL;
+
+	return 0;
+}
+
 /*
  * Checks related to VM-Exit Control Fields
  */
@@ -2515,8 +2524,11 @@ static int nested_check_vm_exit_controls(struct kvm_vcpu *vcpu,
 
 	if (!vmx_control_verify(vmcs12->vm_exit_controls,
 				vmx->nested.msrs.exit_ctls_low,
-				vmx->nested.msrs.exit_ctls_high) ||
-	    nested_vmx_check_exit_msr_switch_controls(vcpu, vmcs12))
+				vmx->nested.msrs.exit_ctls_high))
+		return -EINVAL;
+
+	if ((vmx->nested.dirty_vmcs12) &&
+	    nested_check_vm_exit_controls_full(vcpu, vmcs12))
 		return -EINVAL;
 
 	return 0;
-- 
2.20.1