qemu: Provide support to query the SEV capability

QEMU version >= 2.12 provides support for launching an encrypted VMs on
AMD x86 platform using Secure Encrypted Virtualization (SEV) feature.
This patch adds support to query the SEV capability from the qemu.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>

src/conf/domain_capabilities.c

@@ -67,6 +67,18 @@ virDomainCapsStringValuesFree(virDomainCapsStringValuesPtr values)
 }
 
 
+void
+virSEVCapabilitiesFree(virSEVCapability *cap)
+{
+    if (!cap)
+        return;
+
+    VIR_FREE(cap->pdh);
+    VIR_FREE(cap->cert_chain);
+    VIR_FREE(cap);
+}
+
+
 static void
 virDomainCapsDispose(void *obj)
 {

src/conf/domain_capabilities.h

@@ -137,6 +137,15 @@ struct _virDomainCapsCPU {
     virDomainCapsCPUModelsPtr custom;
 };
 
+typedef struct _virSEVCapability virSEVCapability;
+typedef virSEVCapability *virSEVCapabilityPtr;
+struct _virSEVCapability {
+    char *pdh;
+    char *cert_chain;
+    unsigned int cbitpos;
+    unsigned int reduced_phys_bits;
+};
+
 struct _virDomainCaps {
     virObjectLockable parent;
 
@@ -202,4 +211,7 @@ int virDomainCapsEnumSet(virDomainCapsEnumPtr capsEnum,
 void virDomainCapsEnumClear(virDomainCapsEnumPtr capsEnum);
 
 char * virDomainCapsFormat(virDomainCapsPtr const caps);
+
+void
+virSEVCapabilitiesFree(virSEVCapability *capabilities);
 #endif /* __DOMAIN_CAPABILITIES_H__ */

src/libvirt_private.syms

@@ -185,6 +185,7 @@ virDomainCapsEnumClear;
 virDomainCapsEnumSet;
 virDomainCapsFormat;
 virDomainCapsNew;
+virSEVCapabilitiesFree;
 
 
 # conf/domain_conf.h

src/qemu/qemu_capabilities.c

@@ -497,6 +497,9 @@ VIR_ENUM_IMPL(virQEMUCaps, QEMU_CAPS_LAST,
               "tpm-emulator",
               "mch",
               "mch.extended-tseg-mbytes",
+
+              /* 310 */
+              "sev-guest",
     );
 
 
@@ -563,6 +566,8 @@ struct _virQEMUCaps {
     size_t ngicCapabilities;
     virGICCapability *gicCapabilities;
 
+    virSEVCapability *sevCapabilities;
+
     virQEMUCapsHostCPUData kvmCPU;
     virQEMUCapsHostCPUData tcgCPU;
 };
@@ -1135,6 +1140,7 @@ struct virQEMUCapsStringFlags virQEMUCapsObjectTypes[] = {
     { "vmgenid", QEMU_CAPS_DEVICE_VMGENID },
     { "vhost-vsock-device", QEMU_CAPS_DEVICE_VHOST_VSOCK },
     { "mch", QEMU_CAPS_DEVICE_MCH },
+    { "sev-guest", QEMU_CAPS_SEV_GUEST },
 };
 
 static struct virQEMUCapsStringFlags virQEMUCapsDevicePropsVirtioBalloon[] = {
@@ -2078,6 +2084,16 @@ virQEMUCapsSetGICCapabilities(virQEMUCapsPtr qemuCaps,
 }
 
 
+void
+virQEMUCapsSetSEVCapabilities(virQEMUCapsPtr qemuCaps,
+                              virSEVCapability *capabilities)
+{
+    virSEVCapabilitiesFree(qemuCaps->sevCapabilities);
+
+    qemuCaps->sevCapabilities = capabilities;
+}
+
+
 static int
 virQEMUCapsProbeQMPCommands(virQEMUCapsPtr qemuCaps,
                             qemuMonitorPtr mon)
@@ -2665,6 +2681,21 @@ virQEMUCapsProbeQMPGICCapabilities(virQEMUCapsPtr qemuCaps,
 }
 
 
+static int
+virQEMUCapsProbeQMPSEVCapabilities(virQEMUCapsPtr qemuCaps,
+                                   qemuMonitorPtr mon)
+{
+    virSEVCapability *caps = NULL;
+
+    if (qemuMonitorGetSEVCapabilities(mon, &caps) < 0)
+        return -1;
+
+    virQEMUCapsSetSEVCapabilities(qemuCaps, caps);
+
+    return 0;
+}
+
+
 bool
 virQEMUCapsCPUFilterFeatures(const char *name,
                              void *opaque)
@@ -4064,6 +4095,12 @@ virQEMUCapsInitQMPMonitor(virQEMUCapsPtr qemuCaps,
             virQEMUCapsClear(qemuCaps, QEMU_CAPS_DEVICE_VFIO_CCW);
     }
 
+    /* Probe for SEV capabilities */
+    if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_SEV_GUEST)) {
+        if (virQEMUCapsProbeQMPSEVCapabilities(qemuCaps, mon) < 0)
+            virQEMUCapsClear(qemuCaps, QEMU_CAPS_SEV_GUEST);
+    }
+
     ret = 0;
  cleanup:
     return ret;

src/qemu/qemu_capabilities.h

@@ -482,6 +482,9 @@ typedef enum { /* virQEMUCapsFlags grouping marker for syntax-check */
     QEMU_CAPS_DEVICE_MCH, /* Northbridge in q35 machine types */
     QEMU_CAPS_MCH_EXTENDED_TSEG_MBYTES, /* -global mch.extended-tseg-mbytes */
 
+    /* 310 */
+    QEMU_CAPS_SEV_GUEST, /* -object sev-guest,... */
+
     QEMU_CAPS_LAST /* this must always be the last item */
 } virQEMUCapsFlags;
 
@@ -615,5 +618,4 @@ bool virQEMUCapsGuestIsNative(virArch host,
 
 bool virQEMUCapsCPUFilterFeatures(const char *name,
                                   void *opaque);
-
 #endif /* __QEMU_CAPABILITIES_H__*/

src/qemu/qemu_capspriv.h

@@ -90,6 +90,10 @@ virQEMUCapsSetGICCapabilities(virQEMUCapsPtr qemuCaps,
                               virGICCapability *capabilities,
                               size_t ncapabilities);
 
+void
+virQEMUCapsSetSEVCapabilities(virQEMUCapsPtr qemuCaps,
+                              virSEVCapability *capabilities);
+
 int
 virQEMUCapsProbeQMPCPUDefinitions(virQEMUCapsPtr qemuCaps,
                                   qemuMonitorPtr mon,

src/qemu/qemu_monitor.c

@@ -3849,6 +3849,16 @@ qemuMonitorGetGICCapabilities(qemuMonitorPtr mon,
 }
 
 
+int
+qemuMonitorGetSEVCapabilities(qemuMonitorPtr mon,
+                              virSEVCapability **capabilities)
+{
+    QEMU_CHECK_MONITOR(mon);
+
+    return qemuMonitorJSONGetSEVCapabilities(mon, capabilities);
+}
+
+
 int
 qemuMonitorNBDServerStart(qemuMonitorPtr mon,
                           const char *host,

src/qemu/qemu_monitor.h

@@ -711,6 +711,9 @@ int qemuMonitorSetMigrationCapabilities(qemuMonitorPtr mon,
 int qemuMonitorGetGICCapabilities(qemuMonitorPtr mon,
                                   virGICCapability **capabilities);
 
+int qemuMonitorGetSEVCapabilities(qemuMonitorPtr mon,
+                                  virSEVCapability **capabilities);
+
 typedef enum {
   QEMU_MONITOR_MIGRATE_BACKGROUND       = 1 << 0,
   QEMU_MONITOR_MIGRATE_NON_SHARED_DISK  = 1 << 1, /* migration with non-shared storage with full disk copy */

src/qemu/qemu_monitor_json.c

@@ -6401,6 +6401,85 @@ qemuMonitorJSONGetGICCapabilities(qemuMonitorPtr mon,
     return ret;
 }
 
+
+int
+qemuMonitorJSONGetSEVCapabilities(qemuMonitorPtr mon,
+                                  virSEVCapability **capabilities)
+{
+    int ret = -1;
+    virJSONValuePtr cmd;
+    virJSONValuePtr reply = NULL;
+    virJSONValuePtr caps;
+    virSEVCapability *capability = NULL;
+    const char *pdh = NULL, *cert_chain = NULL;
+    unsigned int cbitpos, reduced_phys_bits;
+
+    *capabilities = NULL;
+
+    if (!(cmd = qemuMonitorJSONMakeCommand("query-sev-capabilities",
+                                           NULL)))
+        return -1;
+
+    if (qemuMonitorJSONCommand(mon, cmd, &reply) < 0)
+        goto cleanup;
+
+
+    if (qemuMonitorJSONCheckError(cmd, reply) < 0)
+        goto cleanup;
+
+    caps = virJSONValueObjectGetObject(reply, "return");
+
+    if (virJSONValueObjectGetNumberUint(caps, "cbitpos", &cbitpos) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("query-sev-capabilities reply was missing"
+                         " 'cbitpos' field"));
+        goto cleanup;
+    }
+
+    if (virJSONValueObjectGetNumberUint(caps, "reduced-phys-bits",
+                                       &reduced_phys_bits) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("query-sev-capabilities reply was missing"
+                         " 'reduced-phys-bits' field"));
+        goto cleanup;
+    }
+
+    if (!(pdh = virJSONValueObjectGetString(caps, "pdh"))) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("query-sev-capabilities reply was missing"
+                         " 'pdh' field"));
+        goto cleanup;
+    }
+
+    if (!(cert_chain = virJSONValueObjectGetString(caps, "cert-chain"))) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("query-sev-capabilities reply was missing"
+                         " 'cert-chain' field"));
+        goto cleanup;
+    }
+
+    if (VIR_ALLOC(capability) < 0)
+        goto cleanup;
+
+    if (VIR_STRDUP(capability->pdh, pdh) < 0)
+        goto cleanup;
+
+    if (VIR_STRDUP(capability->cert_chain, cert_chain) < 0)
+        goto cleanup;
+
+    capability->cbitpos = cbitpos;
+    capability->reduced_phys_bits = reduced_phys_bits;
+    VIR_STEAL_PTR(*capabilities, capability);
+    ret = 0;
+
+ cleanup:
+    virSEVCapabilitiesFree(capability);
+    virJSONValueFree(cmd);
+    virJSONValueFree(reply);
+
+    return ret;
+}
+
 static virJSONValuePtr
 qemuMonitorJSONBuildInetSocketAddress(const char *host,
                                       const char *port)

src/qemu/qemu_monitor_json.h

@@ -152,6 +152,9 @@ int qemuMonitorJSONSetMigrationCapabilities(qemuMonitorPtr mon,
 int qemuMonitorJSONGetGICCapabilities(qemuMonitorPtr mon,
                                       virGICCapability **capabilities);
 
+int qemuMonitorJSONGetSEVCapabilities(qemuMonitorPtr mon,
+                                      virSEVCapability **capabilities);
+
 int qemuMonitorJSONMigrate(qemuMonitorPtr mon,
                            unsigned int flags,
                            const char *uri);

tests/qemucapabilitiesdata/caps_2.12.0.x86_64.replies

@@ -19038,6 +19038,16 @@
   "id": "libvirt-52"
 }
 
+{
+  "return" : {
+   "reduced-phys-bits": 1,
+   "cbitpos": 47,
+   "cert-chain": "AQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAA",
+   "pdh": "AQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAA"
+  },
+  "id": "libvirt-52"
+}
+
 {
   "return": {
   },

tests/qemucapabilitiesdata/caps_2.12.0.x86_64.xml

@@ -210,9 +210,10 @@
   <flag name='tpm-emulator'/>
   <flag name='mch'/>
   <flag name='mch.extended-tseg-mbytes'/>
+  <flag name='sev-guest'/>
   <version>2011090</version>
   <kvmVersion>0</kvmVersion>
-  <microcodeVersion>391586</microcodeVersion>
+  <microcodeVersion>391832</microcodeVersion>
   <package>v2.12.0-rc0</package>
   <arch>x86_64</arch>
   <hostCPU type='kvm' model='base' migratability='yes'>