[PATCH v4 10/34] KVM: SVM: Cannot re-initialize the VMCB after shutdown with SEV-ES

From: Tom Lendacky
Date: Tue Nov 17 2020 - 12:09:22 EST


From: Tom Lendacky <thomas.lendacky@xxxxxxx>

When a SHUTDOWN VMEXIT is encountered, normally the VMCB is re-initialized
so that the guest can be re-launched. But when a guest is running as an
SEV-ES guest, the VMSA cannot be re-initialized because it has been
encrypted. For now, just return -EINVAL to prevent a possible attempt at
a guest reset.

Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
arch/x86/kvm/svm/svm.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 0e5f83912b56..f353039e54b6 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2026,6 +2026,13 @@ static int shutdown_interception(struct vcpu_svm *svm)
{
struct kvm_run *kvm_run = svm->vcpu.run;

+ /*
+ * The VM save area has already been encrypted so it
+ * cannot be reinitialized - just terminate.
+ */
+ if (sev_es_guest(svm->vcpu.kvm))
+ return -EINVAL;
+
/*
* VMCB is undefined after a SHUTDOWN intercept
* so reinitialize it.
--
2.28.0