[PATCH 4/7] KVM: nVMX: Force enlightened VMCS sync from nested_vmx_failValid()

Vitaly Kuznetsov
2021-05-11T11:20:31Z

'need_vmcs12_to_shadow_sync' is used for both shadow and enlightened
VMCS sync when we exit to L1. The comment in nested_vmx_failValid()
validly states why shadow vmcs sync can be omitted but this doesn't
apply to enlightened VMCS as it 'shadows' all VMCS12 fields.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
arch/x86/kvm/vmx/nested.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 7970a16ee6b1..3257a2291693 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -194,9 +194,13 @@ static int nested_vmx_failValid(struct kvm_vcpu *vcpu,
| X86_EFLAGS_ZF);
get_vmcs12(vcpu)->vm_instruction_error = vm_instruction_error;
/*
- * We don't need to force a shadow sync because
- * VM_INSTRUCTION_ERROR is not shadowed
+ * We don't need to force sync to shadow VMCS because
+ * VM_INSTRUCTION_ERROR is not shadowed. Enlightened VMCS 'shadows' all
+ * fields and thus must be synced.
*/
+ if (nested_evmcs_is_used(to_vmx(vcpu)))
+ to_vmx(vcpu)->nested.need_vmcs12_to_shadow_sync = true;
+
return kvm_skip_emulated_instruction(vcpu);
}

--
2.30.2