SEV-ES guests can request termination using the GHCB's MSR protocol. See
AMD's GHCB spec section '4.1.13 Termination Request'. Currently when a
guest does this the userspace VMM sees an KVM_EXIT_UNKNOWN (-EVINAL)
return code from KVM_RUN. By adding a KVM_EXIT_SHUTDOWN_ENTRY to kvm_run
struct the userspace VMM can clearly see the guest has requested a SEV-ES
termination including the termination reason code set and reason code.
Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Suggested-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Peter Gonda <pgonda@xxxxxxxxxx>
---
V4
* Updated to Sean and Paolo's suggestion of reworking the
kvm_run.system_event struct to ndata and data fields to fix the
padding.
V3
* Add Documentation/ update.
* Updated other KVM_EXIT_SHUTDOWN exits to clear ndata and set reason
to KVM_SHUTDOWN_REQ.
V2
* Add KVM_CAP_EXIT_SHUTDOWN_REASON check for KVM_CHECK_EXTENSION.
Tested by making an SEV-ES guest call sev_es_terminate() with hardcoded
reason code set and reason code and then observing the codes from the
userspace VMM in the kvm_run.shutdown.data fields.
---
arch/x86/kvm/svm/sev.c | 9 +++++++--
include/uapi/linux/kvm.h | 5 ++++-
2 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 75fa6dd268f0..1a080f3f09d8 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2735,8 +2735,13 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
pr_info("SEV-ES guest requested termination: %#llx:%#llx\n",
reason_set, reason_code);
- ret = -EINVAL;
- break;
+ vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
+ vcpu->run->system_event.type = KVM_SYSTEM_EVENT_SEV_TERM |
+ KVM_SYSTEM_EVENT_NDATA_VALID;
+ vcpu->run->system_event.ndata = 1;
+ vcpu->run->system_event.data[1] = control->ghcb_gpa;
+
+ return 0;
}
default:
/* Error, keep GHCB MSR value as-is */
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 8616af85dc5d..dd1d8167e71f 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -444,8 +444,11 @@ struct kvm_run {
#define KVM_SYSTEM_EVENT_SHUTDOWN 1
#define KVM_SYSTEM_EVENT_RESET 2
#define KVM_SYSTEM_EVENT_CRASH 3
+#define KVM_SYSTEM_EVENT_SEV_TERM 4
+#define KVM_SYSTEM_EVENT_NDATA_VALID (1u << 31)
__u32 type;
- __u64 flags;
+ __u32 ndata;
+ __u64 data[16];
} system_event;
/* KVM_EXIT_S390_STSI */
struct {
--
2.35.1.1178.g4f1659d476-goog
