[PATCH] Support cpu0-id of Qemu QMP query-sev-capabilities

[Niteesh Dubey]

It allows libvirt to provide the value of cpu0-id retuned by the Qemu QMP
 command query-sev-capabilities as implemented by the Qemu Patch [1] which
 is merged to Qemu master branch and should be available with Qemu 7.1.
 This is used to get the signed Chip Endorsement Key (CEK) of the CPU of AMD
 system from AMD's Key Distribution Service (KDS).

Similar to  cbitpos, reducedPhysBits, maxGuests & maxESGuests;
 the value of cpu0-id is also provided using 'virsh domcapability'.

[1] https://lore.kernel.org/all/20220228093014.882288-1-dovmurik@linux.ibm.com/

Signed-off-by: Niteesh Dubey <niteesh at linux.ibm.com>
---
 include/libvirt/libvirt-host.h | 11 +++++++++++
 src/conf/domain_capabilities.c |  4 ++++
 src/conf/domain_capabilities.h |  1 +
 src/qemu/qemu_capabilities.c   | 12 ++++++++++++
 src/qemu/qemu_driver.c         |  5 +++++
 src/qemu/qemu_monitor_json.c   |  6 ++++++
 6 files changed, 39 insertions(+)

diff --git a/include/libvirt/libvirt-host.h b/include/libvirt/libvirt-host.h
index b5cf8a4a4a..d35abbd9aa 100644
--- a/include/libvirt/libvirt-host.h
+++ b/include/libvirt/libvirt-host.h
@@ -537,6 +537,17 @@ typedef virNodeMemoryStats *virNodeMemoryStatsPtr;
  */
 # define VIR_NODE_SEV_CERT_CHAIN "cert-chain"
 
+/**
+ * VIR_NODE_SEV_CPU0_ID:
+ *
+ * Macro represents the unique ID of CPU0 (socket 0) needed to retrieve
+ * the signed CEK of the CPU from AMD's Key Distribution Service (KDS),
+ * as VIR_TYPED_PARAMS_STRING.
+ *
+ * Since: v8.3.1
+ */
+# define VIR_NODE_SEV_CPU0_ID "cpu0-id"
+
 /**
  * VIR_NODE_SEV_CBITPOS:
  *
diff --git a/src/conf/domain_capabilities.c b/src/conf/domain_capabilities.c
index c394a7a390..2a888da1a9 100644
--- a/src/conf/domain_capabilities.c
+++ b/src/conf/domain_capabilities.c
@@ -601,6 +601,10 @@ virDomainCapsFeatureSEVFormat(virBuffer *buf,
                           sev->max_guests);
         virBufferAsprintf(buf, "<maxESGuests>%d</maxESGuests>\n",
                           sev->max_es_guests);
+        if (sev->cpu0_id != NULL) {
+            virBufferAsprintf(buf, "<cpu0Id>%s</cpu0Id>\n",
+                              sev->cpu0_id);
+        }
         virBufferAdjustIndent(buf, -2);
         virBufferAddLit(buf, "</sev>\n");
     }
diff --git a/src/conf/domain_capabilities.h b/src/conf/domain_capabilities.h
index 1d2f4ac7a5..f2eed80b15 100644
--- a/src/conf/domain_capabilities.h
+++ b/src/conf/domain_capabilities.h
@@ -185,6 +185,7 @@ typedef struct _virSEVCapability virSEVCapability;
 struct _virSEVCapability {
     char *pdh;
     char *cert_chain;
+    char *cpu0_id;
     unsigned int cbitpos;
     unsigned int reduced_phys_bits;
     unsigned int max_guests;
diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index b91db851bb..2d3165e74a 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -1957,6 +1957,9 @@ virQEMUCapsSEVInfoCopy(virSEVCapability **dst,
 
     tmp->pdh = g_strdup(src->pdh);
     tmp->cert_chain = g_strdup(src->cert_chain);
+    if (src->cpu0_id != NULL) {
+        tmp->cpu0_id = g_strdup(src->cpu0_id);
+    }
 
     tmp->cbitpos = src->cbitpos;
     tmp->reduced_phys_bits = src->reduced_phys_bits;
@@ -4693,6 +4696,11 @@ virQEMUCapsFormatSEVInfo(virQEMUCaps *qemuCaps, virBuffer *buf)
     virBufferEscapeString(buf, "<pdh>%s</pdh>\n", sev->pdh);
     virBufferEscapeString(buf, "<certChain>%s</certChain>\n",
                           sev->cert_chain);
+    if (sev->cpu0_id != NULL) {
+        virBufferEscapeString(buf, "<cpu0Id>%s</cpu0Id>\n",
+                              sev->cpu0_id);
+    }
+
     virBufferAdjustIndent(buf, -2);
     virBufferAddLit(buf, "</sev>\n");
 }
@@ -6478,6 +6486,10 @@ virQEMUCapsFillDomainFeatureSEVCaps(virQEMUCaps *qemuCaps,
 
     domCaps->sev->pdh = g_strdup(cap->pdh);
     domCaps->sev->cert_chain = g_strdup(cap->cert_chain);
+    if (cap->cpu0_id != NULL) {
+        domCaps->sev->cpu0_id = g_strdup(cap->cpu0_id);
+    }
+
     domCaps->sev->cbitpos = cap->cbitpos;
     domCaps->sev->reduced_phys_bits = cap->reduced_phys_bits;
     domCaps->sev->max_guests = cap->max_guests;
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index ee0963c30d..464c080409 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -19861,6 +19861,11 @@ qemuGetSEVInfoToParams(virQEMUCaps *qemuCaps,
                                 VIR_NODE_SEV_CERT_CHAIN, sev->cert_chain) < 0)
         goto cleanup;
 
+    if ((sev->cpu0_id != NULL) &&
+       (virTypedParamsAddString(&sevParams, &n, &maxpar,
+                                VIR_NODE_SEV_CPU0_ID, sev->cpu0_id) < 0))
+        goto cleanup;
+
     if (virTypedParamsAddUInt(&sevParams, &n, &maxpar,
                               VIR_NODE_SEV_CBITPOS, sev->cbitpos) < 0)
         goto cleanup;
diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
index 776f4ab2ea..9e611e93e8 100644
--- a/src/qemu/qemu_monitor_json.c
+++ b/src/qemu/qemu_monitor_json.c
@@ -6400,6 +6400,7 @@ qemuMonitorJSONGetSEVCapabilities(qemuMonitor *mon,
     virJSONValue *caps;
     const char *pdh = NULL;
     const char *cert_chain = NULL;
+    const char *cpu0_id = NULL;
     unsigned int cbitpos;
     unsigned int reduced_phys_bits;
     g_autoptr(virSEVCapability) capability = NULL;
@@ -6457,6 +6458,11 @@ qemuMonitorJSONGetSEVCapabilities(qemuMonitor *mon,
 
     capability->cert_chain = g_strdup(cert_chain);
 
+    cpu0_id = virJSONValueObjectGetString(caps, "cpu0-id");
+    if (cpu0_id != NULL) {
+        capability->cpu0_id = g_strdup(cpu0_id);
+    }
+
     capability->cbitpos = cbitpos;
     capability->reduced_phys_bits = reduced_phys_bits;
     *capabilities = g_steal_pointer(&capability);
-- 
2.25.1