2024-04-18 19:56:28

by Michael Roth

[permalink] [raw]
Subject: [PATCH v13 07/26] KVM: SEV: Add GHCB handling for Hypervisor Feature Support requests

From: Brijesh Singh <[email protected]>

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 <[email protected]>
Signed-off-by: Ashish Kalra <[email protected]>
Signed-off-by: Michael Roth <[email protected]>
---
arch/x86/include/asm/sev-common.h | 2 ++
arch/x86/kvm/svm/sev.c | 16 +++++++++++++++-
2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 01261f7054ad..5a8246dd532f 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 6e31cb408dd8..1d2264e93afe 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -33,9 +33,11 @@
#include "cpuid.h"
#include "trace.h"

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

+#define GHCB_HV_FT_SUPPORTED GHCB_HV_FT_SNP
+
/* enable/disable SEV support */
static bool sev_enabled = true;
module_param_named(sev, sev_enabled, bool, 0444);
@@ -2701,6 +2703,7 @@ 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;
@@ -2961,6 +2964,12 @@ 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;

@@ -3085,6 +3094,11 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
ret = 1;
break;
}
+ case SVM_VMGEXIT_HV_FEATURES:
+ ghcb_set_sw_exit_info_2(svm->sev_es.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",
--
2.25.1