Add support for enabling Secure TSC VMSA SEV feature in SEV-SNP guests
through a new "secure-tsc" boolean property on SEV-SNP guest objects. By
default, KVM uses the host TSC frequency for Secure TSC.
Sample command-line:
-machine q35,confidential-guest-support=sev0 \
-object sev-snp-guest,id=sev0,cbitpos=51,reduced-phys-bits=1,secure-tsc=on
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Co-developed-by: Ketan Chaturvedi <Ketan.Chaturvedi@amd.com>
Signed-off-by: Ketan Chaturvedi <Ketan.Chaturvedi@amd.com>
Co-developed-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Naveen N Rao (AMD) <naveen@kernel.org>
---
target/i386/sev.h | 1 +
target/i386/sev.c | 13 +++++++++++++
qapi/qom.json | 6 +++++-
3 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/target/i386/sev.h b/target/i386/sev.h
index 8e09b2ce1976..87e73034ad15 100644
--- a/target/i386/sev.h
+++ b/target/i386/sev.h
@@ -46,6 +46,7 @@ bool sev_snp_enabled(void);
#define SVM_SEV_FEAT_SNP_ACTIVE BIT(0)
#define SVM_SEV_FEAT_DEBUG_SWAP BIT(5)
+#define SVM_SEV_FEAT_SECURE_TSC BIT(9)
typedef struct SevKernelLoaderContext {
char *setup_data;
diff --git a/target/i386/sev.c b/target/i386/sev.c
index e9d84ea25571..68d193402de3 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -3121,6 +3121,16 @@ sev_snp_guest_set_host_data(Object *obj, const char *value, Error **errp)
memcpy(finish->host_data, blob, len);
}
+static bool sev_snp_guest_get_secure_tsc(Object *obj, Error **errp)
+{
+ return is_sev_feature_set(SEV_COMMON(obj), SVM_SEV_FEAT_SECURE_TSC);
+}
+
+static void sev_snp_guest_set_secure_tsc(Object *obj, bool value, Error **errp)
+{
+ sev_set_feature(SEV_COMMON(obj), SVM_SEV_FEAT_SECURE_TSC, value);
+}
+
static void
sev_snp_guest_class_init(ObjectClass *oc, const void *data)
{
@@ -3156,6 +3166,9 @@ sev_snp_guest_class_init(ObjectClass *oc, const void *data)
object_class_property_add_str(oc, "host-data",
sev_snp_guest_get_host_data,
sev_snp_guest_set_host_data);
+ object_class_property_add_bool(oc, "secure-tsc",
+ sev_snp_guest_get_secure_tsc,
+ sev_snp_guest_set_secure_tsc);
}
static void
diff --git a/qapi/qom.json b/qapi/qom.json
index df962d4a5215..52c23e85e349 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -1100,6 +1100,9 @@
# firmware. Set this to true to disable the use of VCEK.
# (default: false) (since: 9.1)
#
+# @secure-tsc: enable Secure TSC
+# (default: false) (since 10.2)
+#
# Since: 9.1
##
{ 'struct': 'SevSnpGuestProperties',
@@ -1111,7 +1114,8 @@
'*id-auth': 'str',
'*author-key-enabled': 'bool',
'*host-data': 'str',
- '*vcek-disabled': 'bool' } }
+ '*vcek-disabled': 'bool',
+ '*secure-tsc': 'bool' } }
##
# @TdxGuestProperties:
--
2.51.0