Currently, check_sev_features() is called in multiple places when
processing IGVM files: both when processing the initial VMSA SEV
features from IGVM, as well as when validating the full contents of the
VMSA. Move this to a single point in sev_common_kvm_init() to simplify
the flow, as well as to re-use this function when VMSA SEV features are
being set without using IGVM files.

Since check_sev_features() relies on SVM_SEV_FEAT_SNP_ACTIVE being set
in VMSA SEV features depending on the guest type, set this flag by
default when creating SEV-SNP guests. When using IGVM files, this field
is anyway over-written so that validation in check_sev_features() is
still relevant.

Finally, add a check to ensure SEV features aren't also set through qemu
cli if using IGVM files.

Signed-off-by: Naveen N Rao (AMD) <naveen@kernel.org>
---
 target/i386/sev.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/target/i386/sev.c b/target/i386/sev.c
index 1057b8ab2c60..243e9493ba8d 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -586,9 +586,6 @@ static int check_vmsa_supported(SevCommonState *sev_common, hwaddr gpa,
     vmsa_check.x87_fcw = 0;
     vmsa_check.mxcsr = 0;
 
-    if (check_sev_features(sev_common, vmsa_check.sev_features, errp) < 0) {
-        return -1;
-    }
     vmsa_check.sev_features = 0;
 
     if (!buffer_is_zero(&vmsa_check, sizeof(vmsa_check))) {
@@ -1892,20 +1889,29 @@ static int sev_common_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
          * as SEV_STATE_UNINIT.
          */
         if (x86machine->igvm) {
+            if (sev_common->sev_features & ~SVM_SEV_FEAT_SNP_ACTIVE) {
+                error_setg(errp, "%s: SEV features can't be specified when using IGVM files",
+                           __func__);
+                return -1;
+            }
             if (IGVM_CFG_GET_CLASS(x86machine->igvm)
                     ->process(x86machine->igvm, machine->cgs, true, errp) ==
                 -1) {
                 return -1;
             }
-            /*
-             * KVM maintains a bitmask of allowed sev_features. This does not
-             * include SVM_SEV_FEAT_SNP_ACTIVE which is set accordingly by KVM
-             * itself. Therefore we need to clear this flag.
-             */
-            args.vmsa_features = sev_common->sev_features &
-                                 ~SVM_SEV_FEAT_SNP_ACTIVE;
         }
 
+        if (check_sev_features(sev_common, sev_common->sev_features, errp) < 0) {
+            return -1;
+        }
+
+        /*
+         * KVM maintains a bitmask of allowed sev_features. This does not
+         * include SVM_SEV_FEAT_SNP_ACTIVE which is set accordingly by KVM
+         * itself. Therefore we need to clear this flag.
+         */
+        args.vmsa_features = sev_common->sev_features & ~SVM_SEV_FEAT_SNP_ACTIVE;
+
         ret = sev_ioctl(sev_common->sev_fd, KVM_SEV_INIT2, &args, &fw_error);
         break;
     }
@@ -2518,9 +2524,6 @@ static int cgs_set_guest_state(hwaddr gpa, uint8_t *ptr, uint64_t len,
                            __func__);
                 return -1;
             }
-            if (check_sev_features(sev_common, sa->sev_features, errp) < 0) {
-                return -1;
-            }
             sev_common->sev_features = sa->sev_features;
         }
         return 0;
@@ -3127,6 +3130,7 @@ sev_snp_guest_instance_init(Object *obj)
 
     /* default init/start/finish params for kvm */
     sev_snp_guest->kvm_start_conf.policy = DEFAULT_SEV_SNP_POLICY;
+    SEV_COMMON(sev_snp_guest)->sev_features |= SVM_SEV_FEAT_SNP_ACTIVE;
 }
 
 /* guest info specific to sev-snp */
-- 
2.50.1

SEV features in the VMSA are only meaningful for SEV-ES and SEV-SNP
guests, as they control aspects of the encrypted guest state that are
not relevant for basic SEV guests.

Add a check in check_sev_features() to ensure that SEV-ES or SEV-SNP is
enabled when any SEV features are specified.

Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Naveen N Rao (AMD) <naveen@kernel.org>
---
 target/i386/sev.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/target/i386/sev.c b/target/i386/sev.c
index 243e9493ba8d..fa23b5c38e9b 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -509,6 +509,12 @@ static int check_sev_features(SevCommonState *sev_common, uint64_t sev_features,
             __func__);
         return -1;
     }
+    if (sev_features && !sev_es_enabled()) {
+        error_setg(errp,
+                   "%s: SEV features require either SEV-ES or SEV-SNP to be enabled",
+                   __func__);
+        return -1;
+    }
     if (sev_features & ~sev_common->supported_sev_features) {
         error_setg(errp,
                    "%s: VMSA contains unsupported sev_features: %lX, "
-- 
2.50.1

Add support for enabling debug-swap VMSA SEV feature in SEV-ES and
SEV-SNP guests through a new "debug-swap" boolean property on SEV guest
objects. Though the boolean property is available for plain SEV guests,
check_sev_features() will reject setting this for plain SEV guests.

Add helpers for setting and querying the VMSA SEV features so that they
can be re-used for subsequent VMSA SEV features, and convert the
existing SVM_SEV_FEAT_SNP_ACTIVE definition to use the BIT() macro for
consistency with the new feature flag.

Sample command-line:
  -machine q35,confidential-guest-support=sev0 \
  -object sev-snp-guest,id=sev0,cbitpos=51,reduced-phys-bits=1,debug-swap=on

Signed-off-by: Naveen N Rao (AMD) <naveen@kernel.org>
---
 target/i386/sev.h |  3 ++-
 target/i386/sev.c | 29 +++++++++++++++++++++++++++++
 qapi/qom.json     |  6 +++++-
 3 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/target/i386/sev.h b/target/i386/sev.h
index 9db1a802f6bb..8e09b2ce1976 100644
--- a/target/i386/sev.h
+++ b/target/i386/sev.h
@@ -44,7 +44,8 @@ bool sev_snp_enabled(void);
 #define SEV_SNP_POLICY_SMT      0x10000
 #define SEV_SNP_POLICY_DBG      0x80000
 
-#define SVM_SEV_FEAT_SNP_ACTIVE 1
+#define SVM_SEV_FEAT_SNP_ACTIVE     BIT(0)
+#define SVM_SEV_FEAT_DEBUG_SWAP     BIT(5)
 
 typedef struct SevKernelLoaderContext {
     char *setup_data;
diff --git a/target/i386/sev.c b/target/i386/sev.c
index fa23b5c38e9b..b3e4d0f2c1d5 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -319,6 +319,20 @@ sev_set_guest_state(SevCommonState *sev_common, SevState new_state)
     sev_common->state = new_state;
 }
 
+static bool is_sev_feature_set(SevCommonState *sev_common, uint64_t feature)
+{
+    return !!(sev_common->sev_features & feature);
+}
+
+static void sev_set_feature(SevCommonState *sev_common, uint64_t feature, bool value)
+{
+    if (value) {
+        sev_common->sev_features |= feature;
+    } else {
+        sev_common->sev_features &= ~feature;
+    }
+}
+
 static void
 sev_ram_block_added(RAMBlockNotifier *n, void *host, size_t size,
                     size_t max_size)
@@ -2732,6 +2746,16 @@ static int cgs_set_guest_policy(ConfidentialGuestPolicyType policy_type,
     return 0;
 }
 
+static bool sev_common_get_debug_swap(Object *obj, Error **errp)
+{
+    return is_sev_feature_set(SEV_COMMON(obj), SVM_SEV_FEAT_DEBUG_SWAP);
+}
+
+static void sev_common_set_debug_swap(Object *obj, bool value, Error **errp)
+{
+    sev_set_feature(SEV_COMMON(obj), SVM_SEV_FEAT_DEBUG_SWAP, value);
+}
+
 static void
 sev_common_class_init(ObjectClass *oc, const void *data)
 {
@@ -2749,6 +2773,11 @@ sev_common_class_init(ObjectClass *oc, const void *data)
                                    sev_common_set_kernel_hashes);
     object_class_property_set_description(oc, "kernel-hashes",
             "add kernel hashes to guest firmware for measured Linux boot");
+    object_class_property_add_bool(oc, "debug-swap",
+                                   sev_common_get_debug_swap,
+                                   sev_common_set_debug_swap);
+    object_class_property_set_description(oc, "debug-swap",
+            "enable virtualization of debug registers");
 }
 
 static void
diff --git a/qapi/qom.json b/qapi/qom.json
index 830cb2ffe781..71cd8ad588b5 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -1010,13 +1010,17 @@
 #     designated guest firmware page for measured boot with -kernel
 #     (default: false) (since 6.2)
 #
+# @debug-swap: enable virtualization of debug registers (default: false)
+#              (since 10.2)
+#
 # Since: 9.1
 ##
 { 'struct': 'SevCommonProperties',
   'data': { '*sev-device': 'str',
             '*cbitpos': 'uint32',
             'reduced-phys-bits': 'uint32',
-            '*kernel-hashes': 'bool' } }
+            '*kernel-hashes': 'bool',
+            '*debug-swap': 'bool' } }
 
 ##
 # @SevGuestProperties:
-- 
2.50.1

Now that users can enable VMSA SEV features, update sev_init2_required()
to return true if any SEV features are requested. This enables qemu to
use KVM_SEV_INIT2 for SEV-ES guests when necessary.

Sample command-line:
  -machine q35,confidential-guest-support=sev0 \
  -object sev-guest,id=sev0,policy=0x5,cbitpos=51,reduced-phys-bits=1,debug-swap=on

Reviewed-by: Nikunj A Dadhania <nikunj@amd.com>
Signed-off-by: Naveen N Rao (AMD) <naveen@kernel.org>
---
 target/i386/sev.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/target/i386/sev.c b/target/i386/sev.c
index b3e4d0f2c1d5..3063ad2d077a 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -1704,8 +1704,7 @@ sev_vm_state_change(void *opaque, bool running, RunState state)
  */
 static bool sev_init2_required(SevGuestState *sev_guest)
 {
-    /* Currently no KVM_SEV_INIT2-specific options are exposed via QEMU */
-    return false;
+    return !!SEV_COMMON(sev_guest)->sev_features;
 }
 
 static int sev_kvm_type(X86ConfidentialGuest *cg)
-- 
2.50.1

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.

Sample command-line:
  -machine q35,confidential-guest-support=sev0 \
  -object sev-snp-guest,id=sev0,cbitpos=51,reduced-phys-bits=1,secure-tsc=on

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     |  5 ++++-
 3 files changed, 18 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 3063ad2d077a..8f88df19a408 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -3117,6 +3117,16 @@ 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)
 {
@@ -3152,6 +3162,9 @@ 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 71cd8ad588b5..b05a475ef499 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -1100,6 +1100,8 @@
 #     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 +1113,8 @@
             '*id-auth': 'str',
             '*author-key-enabled': 'bool',
             '*host-data': 'str',
-            '*vcek-disabled': 'bool' } }
+            '*vcek-disabled': 'bool',
+            '*secure-tsc': 'bool' } }
 
 ##
 # @TdxGuestProperties:
-- 
2.50.1

Add support for configuring the TSC frequency when Secure TSC is enabled
in SEV-SNP guests through a new "tsc-frequency" property on SEV-SNP
guest objects, similar to the vCPU-specific property used by regular
guests and TDX. A new property is needed since SEV-SNP guests require
the TSC frequency to be specified during early SNP_LAUNCH_START command
before any vCPUs are created.

The user-provided TSC frequency is set through KVM_SET_TSC_KHZ before
issuing KVM_SEV_SNP_LAUNCH_START.

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.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 qapi/qom.json     |  6 +++++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/target/i386/sev.c b/target/i386/sev.c
index 8f88df19a408..facf51c810d9 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -178,6 +178,7 @@ struct SevSnpGuestState {
     char *id_auth_base64;
     uint8_t *id_auth;
     char *host_data;
+    uint32_t tsc_khz;
 
     struct kvm_sev_snp_launch_start kvm_start_conf;
     struct kvm_sev_snp_launch_finish kvm_finish_conf;
@@ -536,6 +537,13 @@ static int check_sev_features(SevCommonState *sev_common, uint64_t sev_features,
                    __func__, sev_features, sev_common->supported_sev_features);
         return -1;
     }
+    if (sev_snp_enabled() && SEV_SNP_GUEST(sev_common)->tsc_khz &&
+        !(sev_features & SVM_SEV_FEAT_SECURE_TSC)) {
+        error_setg(errp,
+                   "%s: TSC frequency can only be set if Secure TSC is enabled",
+                   __func__);
+        return -1;
+    }
     return 0;
 }
 
@@ -1085,6 +1093,18 @@ sev_snp_launch_start(SevCommonState *sev_common)
             return 1;
     }
 
+    if (is_sev_feature_set(sev_common, SVM_SEV_FEAT_SECURE_TSC)) {
+        rc = -EINVAL;
+        if (kvm_check_extension(kvm_state, KVM_CAP_VM_TSC_CONTROL)) {
+            rc = kvm_vm_ioctl(kvm_state, KVM_SET_TSC_KHZ, sev_snp_guest->tsc_khz);
+        }
+        if (rc < 0) {
+            error_report("%s: Unable to set Secure TSC frequency to %u kHz ret=%d",
+                         __func__, sev_snp_guest->tsc_khz, rc);
+            return 1;
+        }
+    }
+
     rc = sev_ioctl(sev_common->sev_fd, KVM_SEV_SNP_LAUNCH_START,
                    start, &fw_error);
     if (rc < 0) {
@@ -3127,6 +3147,28 @@ 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_get_tsc_frequency(Object *obj, Visitor *v, const char *name,
+                                void *opaque, Error **errp)
+{
+    uint32_t value = SEV_SNP_GUEST(obj)->tsc_khz * 1000;
+
+    visit_type_uint32(v, name, &value, errp);
+}
+
+static void
+sev_snp_guest_set_tsc_frequency(Object *obj, Visitor *v, const char *name,
+                                void *opaque, Error **errp)
+{
+    uint32_t value;
+
+    if (!visit_type_uint32(v, name, &value, errp)) {
+        return;
+    }
+
+    SEV_SNP_GUEST(obj)->tsc_khz = value / 1000;
+}
+
 static void
 sev_snp_guest_class_init(ObjectClass *oc, const void *data)
 {
@@ -3165,6 +3207,9 @@ sev_snp_guest_class_init(ObjectClass *oc, const void *data)
     object_class_property_add_bool(oc, "secure-tsc",
                                   sev_snp_guest_get_secure_tsc,
                                   sev_snp_guest_set_secure_tsc);
+    object_class_property_add(oc, "tsc-frequency", "uint32",
+                              sev_snp_guest_get_tsc_frequency,
+                              sev_snp_guest_set_tsc_frequency, NULL, NULL);
 }
 
 static void
diff --git a/qapi/qom.json b/qapi/qom.json
index b05a475ef499..5b99148cb790 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -1102,6 +1102,9 @@
 #
 # @secure-tsc: enable Secure TSC (default: false) (since 10.2)
 #
+# @tsc-frequency: set secure TSC frequency. Only valid if Secure TSC
+#     is enabled (default: zero) (since 10.2)
+#
 # Since: 9.1
 ##
 { 'struct': 'SevSnpGuestProperties',
@@ -1114,7 +1117,8 @@
             '*author-key-enabled': 'bool',
             '*host-data': 'str',
             '*vcek-disabled': 'bool',
-            '*secure-tsc': 'bool' } }
+            '*secure-tsc': 'bool',
+            '*tsc-frequency': 'uint32' } }
 
 ##
 # @TdxGuestProperties:
-- 
2.50.1

Add support for enabling Secure AVIC VMSA SEV feature in SEV-SNP guests
through a new "secure-avic" boolean property on SEV-SNP guest objects.

Sample command-line:
  -machine q35,confidential-guest-support=sev0 \
  -object sev-snp-guest,id=sev0,cbitpos=51,reduced-phys-bits=1,secure-avic=on

Reviewed-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     |  5 ++++-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/target/i386/sev.h b/target/i386/sev.h
index 87e73034ad15..a374c144bccd 100644
--- a/target/i386/sev.h
+++ b/target/i386/sev.h
@@ -47,6 +47,7 @@ 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)
+#define SVM_SEV_FEAT_SECURE_AVIC    BIT(16)
 
 typedef struct SevKernelLoaderContext {
     char *setup_data;
diff --git a/target/i386/sev.c b/target/i386/sev.c
index facf51c810d9..f9170e21ca57 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -3147,6 +3147,16 @@ 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 bool sev_snp_guest_get_secure_avic(Object *obj, Error **errp)
+{
+    return is_sev_feature_set(SEV_COMMON(obj), SVM_SEV_FEAT_SECURE_AVIC);
+}
+
+static void sev_snp_guest_set_secure_avic(Object *obj, bool value, Error **errp)
+{
+    sev_set_feature(SEV_COMMON(obj), SVM_SEV_FEAT_SECURE_AVIC, value);
+}
+
 static void
 sev_snp_guest_get_tsc_frequency(Object *obj, Visitor *v, const char *name,
                                 void *opaque, Error **errp)
@@ -3210,6 +3220,9 @@ sev_snp_guest_class_init(ObjectClass *oc, const void *data)
     object_class_property_add(oc, "tsc-frequency", "uint32",
                               sev_snp_guest_get_tsc_frequency,
                               sev_snp_guest_set_tsc_frequency, NULL, NULL);
+    object_class_property_add_bool(oc, "secure-avic",
+                                  sev_snp_guest_get_secure_avic,
+                                  sev_snp_guest_set_secure_avic);
 }
 
 static void
diff --git a/qapi/qom.json b/qapi/qom.json
index 5b99148cb790..5dce560a2f54 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -1105,6 +1105,8 @@
 # @tsc-frequency: set secure TSC frequency. Only valid if Secure TSC
 #     is enabled (default: zero) (since 10.2)
 #
+# @secure-avic: enable Secure AVIC (default: false) (since 10.2)
+#
 # Since: 9.1
 ##
 { 'struct': 'SevSnpGuestProperties',
@@ -1118,7 +1120,8 @@
             '*host-data': 'str',
             '*vcek-disabled': 'bool',
             '*secure-tsc': 'bool',
-            '*tsc-frequency': 'uint32' } }
+            '*tsc-frequency': 'uint32',
+            '*secure-avic': 'bool' } }
 
 ##
 # @TdxGuestProperties:
-- 
2.50.1