KVM: nVMX: Avoid reading VM_EXIT_INTR_ERROR_CODE needlessly on nested exits

We only need to update vm_exit_intr_error_code if there is a valid exit
interruption information and it comes with a valid error code.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 5e6391112275..71755573b7ca 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7426,7 +7426,11 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
         vmcs12->exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
 
         vmcs12->vm_exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
-        vmcs12->vm_exit_intr_error_code = vmcs_read32(VM_EXIT_INTR_ERROR_CODE);
+        if ((vmcs12->vm_exit_intr_info &
+             (INTR_INFO_VALID_MASK | INTR_INFO_DELIVER_CODE_MASK)) ==
+            (INTR_INFO_VALID_MASK | INTR_INFO_DELIVER_CODE_MASK))
+                vmcs12->vm_exit_intr_error_code =
+                        vmcs_read32(VM_EXIT_INTR_ERROR_CODE);
         vmcs12->idt_vectoring_info_field = 0;
         vmcs12->vm_exit_instruction_len = vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
         vmcs12->vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);