[PATCH RFC v8 30/56] KVM: SVM: Provide the Hypervisor Feature support VMGEXIT

From: Michael Roth
Date: Mon Feb 20 2023 - 13:53:10 EST


From: Brijesh Singh <brijesh.singh@xxxxxxx>

Version 2 of the GHCB specification introduced advertisement of features
that are supported by the Hypervisor.

Now that KVM supports version 2 of the GHCB specification, bump the
maximum supported protocol version.

Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
---
arch/x86/include/asm/sev-common.h | 2 ++
arch/x86/kvm/svm/sev.c | 14 ++++++++++++++
arch/x86/kvm/svm/svm.h | 3 ++-
3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index e15548d88f2a..539de6b93420 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -101,6 +101,8 @@ enum psc_op {
/* GHCB Hypervisor Feature Request/Response */
#define GHCB_MSR_HV_FT_REQ 0x080
#define GHCB_MSR_HV_FT_RESP 0x081
+#define GHCB_MSR_HV_FT_POS 12
+#define GHCB_MSR_HV_FT_MASK GENMASK_ULL(51, 0)
#define GHCB_MSR_HV_FT_RESP_VAL(v) \
/* GHCBData[63:12] */ \
(((u64)(v) & GENMASK_ULL(63, 12)) >> 12)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 05eda0940e22..c1f0d4898ce3 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2675,6 +2675,7 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
case SVM_VMGEXIT_AP_HLT_LOOP:
case SVM_VMGEXIT_AP_JUMP_TABLE:
case SVM_VMGEXIT_UNSUPPORTED_EVENT:
+ case SVM_VMGEXIT_HV_FEATURES:
break;
default:
reason = GHCB_ERR_INVALID_EVENT;
@@ -2941,6 +2942,13 @@ static int sev_handle_vmgexit_msr_protocol(struct vcpu_svm *svm)
GHCB_MSR_INFO_MASK,
GHCB_MSR_INFO_POS);
break;
+ case GHCB_MSR_HV_FT_REQ: {
+ set_ghcb_msr_bits(svm, GHCB_HV_FT_SUPPORTED,
+ GHCB_MSR_HV_FT_MASK, GHCB_MSR_HV_FT_POS);
+ set_ghcb_msr_bits(svm, GHCB_MSR_HV_FT_RESP,
+ GHCB_MSR_INFO_MASK, GHCB_MSR_INFO_POS);
+ break;
+ }
case GHCB_MSR_TERM_REQ: {
u64 reason_set, reason_code;

@@ -3065,6 +3073,12 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
ret = 1;
break;
}
+ case SVM_VMGEXIT_HV_FEATURES: {
+ ghcb_set_sw_exit_info_2(ghcb, GHCB_HV_FT_SUPPORTED);
+
+ ret = 1;
+ break;
+ }
case SVM_VMGEXIT_UNSUPPORTED_EVENT:
vcpu_unimpl(vcpu,
"vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n",
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index f4848e6aba28..c249c360fe36 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -662,9 +662,10 @@ void avic_refresh_virtual_apic_mode(struct kvm_vcpu *vcpu);

/* sev.c */

-#define GHCB_VERSION_MAX 1ULL
+#define GHCB_VERSION_MAX 2ULL
#define GHCB_VERSION_MIN 1ULL

+#define GHCB_HV_FT_SUPPORTED 0

extern unsigned int max_sev_asid;

--
2.25.1