[libvirt] [PATCH v9 06/11] conf: introduce launch-security element in domain

Brijesh Singh posted 11 patches 23 weeks ago

[libvirt] [PATCH v9 06/11] conf: introduce launch-security element in domain

Posted by Brijesh Singh 23 weeks ago
The launch-security element can be used to define the security
model to use when launching a domain. Currently we support 'sev'.

When 'sev' is used, the VM will be launched with AMD SEV feature enabled.
SEV feature supports running encrypted VM under the control of KVM.
Encrypted VMs have their pages (code and data) secured such that only the
guest itself has access to the unencrypted version. Each encrypted VM is
associated with a unique encryption key; if its data is accessed to a
different entity using a different key the encrypted guests data will be
incorrectly decrypted, leading to unintelligible data.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
---
 docs/formatdomain.html.in                          | 115 ++++++++++++++++++
 docs/schemas/domaincommon.rng                      |  37 ++++++
 src/conf/domain_conf.c                             | 133 +++++++++++++++++++++
 src/conf/domain_conf.h                             |  27 +++++
 tests/genericxml2xmlindata/launch-security-sev.xml |  24 ++++
 tests/genericxml2xmltest.c                         |   2 +
 6 files changed, 338 insertions(+)
 create mode 100644 tests/genericxml2xmlindata/launch-security-sev.xml

diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 6912762..77845fe 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -8458,6 +8458,121 @@ qemu-kvm -net nic,model=? /dev/null
 
     <p>Note: DEA/TDEA is synonymous with DES/TDES.</p>
 
+    <h3><a id="sev">Secure Encrypted Virtualization (SEV)</a></h3>
+
+    <p>
+       The contents of the <code>&lt;launch-security type='sev'&gt;</code> element
+       is used to provide the guest owners input used for creating an encrypted
+       VM using the AMD SEV feature.
+
+       SEV is an extension to the AMD-V architecture which supports running
+       encrypted virtual machine (VMs) under the control of KVM. Encrypted
+       VMs have their pages (code and data) secured such that only the guest
+       itself has access to the unencrypted version. Each encrypted VM is
+       associated with a unique encryption key; if its data is accessed to a
+       different entity using a different key the encrypted guests data will
+       be incorrectly decrypted, leading to unintelligible data.
+
+       For more information see various input parameters and its format see the SEV API spec
+       <a href="https://support.amd.com/TechDocs/55766_SEV-KM%20API_Specification.pdf"> https://support.amd.com/TechDocs/55766_SEV-KM%20API_Specification.pdf </a>
+       <span class="since">Since 4.4.0</span>
+       </p>
+    <pre>
+&lt;domain&gt;
+  ...
+  &lt;launch-security type='sev'&gt;
+    &lt;policy&gt; 0x0001 &lt;/policy&gt;
+    &lt;cbitpos&gt; 47 &lt;/cbitpos&gt;
+    &lt;reduced-phys-bits&gt; 1 &lt;/reduced-phys-bits&gt;
+    &lt;session&gt; AAACCCDD=FFFCCCDSDS &lt;/session&gt;
+    &lt;dh-cert&gt; RBBBSDDD=FDDCCCDDDG &lt;/dh&gt;
+  &lt;/sev&gt;
+  ...
+&lt;/domain&gt;
+</pre>
+
+    <dl>
+      <dt><code>cbitpos</code></dt>
+      <dd>The required <code>cbitpos</code> element provides the C-bit (aka encryption bit)
+      location in guest page table entry. The value of <code>cbitpos</code> is
+      hypervisor dependent and can be obtained through the <code>sev</code> element
+      from the domain capabilities.
+      </dd>
+      <dt><code>reduced-phys-bits</code></dt>
+      <dd>The required <code>reduced-phys-bits</code> element provides the physical
+      address bit reducation. Similar to <code>cbitpos</code> the value of <code>
+      reduced-phys-bit</code> is hypervisor dependent and can be obtained
+      through the <code>sev</code> element from the domain capabilities.
+      </dd>
+      <dt><code>policy</code></dt>
+      <dd>The required <code>policy</code> element provides the guest policy
+      which must be maintained by the SEV firmware. This policy is enforced by
+      the firmware and restricts what configuration and operational commands
+      can be performed on this guest by the hypervisor. The guest policy
+      provided during guest launch is bound to the guest and cannot be changed
+      throughout the lifetime of the guest. The policy is also transmitted
+      during snapshot and migration flows and enforced on the destination platform.
+
+      The guest policy is a 4 unsigned byte with the fields shown in Table:
+
+      <table class="top_table">
+        <tr>
+          <th> Bit(s) </th>
+          <th> Description </th>
+        </tr>
+        <tr>
+          <td> 0 </td>
+          <td> Debugging of the guest is disallowed when set </td>
+        </tr>
+        <tr>
+          <td> 1 </td>
+          <td> Sharing keys with other guests is disallowed when set </td>
+        </tr>
+        <tr>
+          <td> 2 </td>
+          <td> SEV-ES is required when set</td>
+        </tr>
+        <tr>
+          <td> 3 </td>
+          <td> Sending the guest to another platform is disallowed when set</td>
+        </tr>
+        <tr>
+          <td> 4 </td>
+          <td> The guest must not be transmitted to another platform that is
+               not in the domain when set. </td>
+        </tr>
+        <tr>
+          <td> 5 </td>
+          <td> The guest must not be transmitted to another platform that is
+               not SEV capable when set. </td>
+        </tr>
+        <tr>
+          <td> 6:15 </td>
+          <td> reserved </td>
+        </tr>
+        <tr>
+          <td> 16:32 </td>
+          <td> The guest must not be transmitted to another platform with a
+               lower firmware version. </td>
+        </tr>
+      </table>
+
+      </dd>
+      <dt><code>dh-cert</code></dt>
+      <dd>The optional <code>dh-cert</code> element provides the guest owners
+      base64 encoded Diffie-Hellman (DH) key. The key is used to negotiate a
+      master secret key between the SEV firmware and guest owner. This master
+      secret key is then used to establish a trusted channel between SEV
+      firmware and guest owner.
+      </dd>
+      <dt><code>session</code></dt>
+      <dd>The optional <code>session</code> element provides the guest owners
+      base64 encoded session blob defined in the SEV API spec.
+
+      See SEV spec LAUNCH_START section for the session blob format.
+      </dd>
+    </dl>
+
     <h2><a id="examples">Example configs</a></h2>
 
     <p>
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 550fb10..1d06a5e 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -77,6 +77,9 @@
         <optional>
           <ref name='keywrap'/>
         </optional>
+        <optional>
+          <ref name='launch-security'/>
+        </optional>
       </interleave>
     </element>
   </define>
@@ -436,6 +439,40 @@
     </element>
   </define>
 
+  <define name="launch-security">
+    <element name="launch-security">
+      <attribute name="type">
+        <value>sev</value>
+      </attribute>
+      <interleave>
+        <element name="cbitpos">
+          <data type='unsignedInt'/>
+        </element>
+        <element name="reduced-phys-bits">
+          <data type='unsignedInt'/>
+        </element>
+        <element name="policy">
+          <ref name='hexuint'/>
+        </element>
+        <optional>
+          <element name="handle">
+            <ref name='unsignedInt'/>
+          </element>
+        </optional>
+        <optional>
+          <element name="dh-cert">
+            <data type="string"/>
+          </element>
+        </optional>
+        <optional>
+          <element name="session">
+            <data type="string"/>
+          </element>
+        </optional>
+      </interleave>
+    </element>
+  </define>
+
   <!--
       Enable or disable perf events for the domain. For each
       of the events the following rules apply:
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index ab93bb7..c4a609c 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -944,6 +944,10 @@ VIR_ENUM_IMPL(virDomainShmemModel, VIR_DOMAIN_SHMEM_MODEL_LAST,
               "ivshmem-plain",
               "ivshmem-doorbell")
 
+VIR_ENUM_IMPL(virDomainLaunchSecurity, VIR_DOMAIN_LAUNCH_SECURITY_LAST,
+              "",
+              "sev")
+
 static virClassPtr virDomainObjClass;
 static virClassPtr virDomainXMLOptionClass;
 static void virDomainObjDispose(void *obj);
@@ -2957,6 +2961,19 @@ virDomainCachetuneDefFree(virDomainCachetuneDefPtr cachetune)
 }
 
 
+static void
+virDomainSEVDefFree(virDomainSevDefPtr def)
+{
+    if (!def)
+        return;
+
+    VIR_FREE(def->dh_cert);
+    VIR_FREE(def->session);
+
+    VIR_FREE(def);
+}
+
+
 void virDomainDefFree(virDomainDefPtr def)
 {
     size_t i;
@@ -3139,6 +3156,8 @@ void virDomainDefFree(virDomainDefPtr def)
     if (def->namespaceData && def->ns.free)
         (def->ns.free)(def->namespaceData);
 
+    virDomainSEVDefFree(def->sev);
+
     xmlFreeNode(def->metadata);
 
     VIR_FREE(def);
@@ -15826,6 +15845,85 @@ virDomainMemoryTargetDefParseXML(xmlNodePtr node,
 }
 
 
+static virDomainSevDefPtr
+virDomainSEVDefParseXML(xmlNodePtr sevNode,
+                        xmlXPathContextPtr ctxt)
+{
+    char *tmp = NULL;
+    char *type = NULL;
+    xmlNodePtr save = ctxt->node;
+    virDomainSevDefPtr def;
+    unsigned long policy;
+
+    ctxt->node = sevNode;
+
+    if (VIR_ALLOC(def) < 0)
+        return NULL;
+
+    if (!(type = virXMLPropString(sevNode, "type"))) {
+        virReportError(VIR_ERR_XML_ERROR, "%s",
+                       _("missing launch-security type"));
+        goto error;
+    }
+
+    def->sectype = virDomainLaunchSecurityTypeFromString(type);
+    switch ((virDomainLaunchSecurity) def->sectype) {
+    case VIR_DOMAIN_LAUNCH_SECURITY_SEV:
+        break;
+    case VIR_DOMAIN_LAUNCH_SECURITY_NONE:
+    case VIR_DOMAIN_LAUNCH_SECURITY_LAST:
+    default:
+        virReportError(VIR_ERR_XML_ERROR,
+                       _("unsupported launch-security type '%s'"),
+                       type);
+        goto error;
+    }
+
+    if (virXPathUInt("string(./cbitpos)", ctxt, &def->cbitpos) < 0) {
+        virReportError(VIR_ERR_XML_ERROR, "%s",
+                       _("failed to get launch-security cbitpos"));
+        goto error;
+    }
+
+    if (virXPathUInt("string(./reduced-phys-bits)", ctxt,
+                     &def->reduced_phys_bits) < 0) {
+        virReportError(VIR_ERR_XML_ERROR, "%s",
+                       _("failed to get launch-security reduced-phys-bits"));
+        goto error;
+    }
+
+    if (virXPathULongHex("string(./policy)", ctxt, &policy) < 0) {
+        virReportError(VIR_ERR_XML_ERROR, "%s",
+                       _("failed to get launch-security policy"));
+        goto error;
+    }
+
+    def->policy = policy;
+
+    if ((tmp = virXPathString("string(./dh-cert)", ctxt))) {
+        if (VIR_STRDUP(def->dh_cert, tmp) < 0)
+            goto error;
+
+        VIR_FREE(tmp);
+    }
+
+    if ((tmp = virXPathString("string(./session)", ctxt))) {
+        if (VIR_STRDUP(def->session, tmp) < 0)
+            goto error;
+
+        VIR_FREE(tmp);
+    }
+
+    ctxt->node = save;
+    return def;
+
+ error:
+    VIR_FREE(tmp);
+    virDomainSEVDefFree(def);
+    ctxt->node = save;
+    return NULL;
+}
+
 static virDomainMemoryDefPtr
 virDomainMemoryDefParseXML(virDomainXMLOptionPtr xmlopt,
                            xmlNodePtr memdevNode,
@@ -20631,6 +20729,13 @@ virDomainDefParseXML(xmlDocPtr xml,
     ctxt->node = node;
     VIR_FREE(nodes);
 
+    /* Check for SEV feature */
+    if ((node = virXPathNode("./launch-security", ctxt)) != NULL) {
+        def->sev = virDomainSEVDefParseXML(node, ctxt);
+        if (!def->sev)
+            goto error;
+    }
+
     /* analysis of memory devices */
     if ((n = virXPathNodeSet("./devices/memory", ctxt, &nodes)) < 0)
         goto error;
@@ -26642,6 +26747,32 @@ virDomainKeyWrapDefFormat(virBufferPtr buf, virDomainKeyWrapDefPtr keywrap)
     virBufferAddLit(buf, "</keywrap>\n");
 }
 
+
+static void
+virDomainSEVDefFormat(virBufferPtr buf, virDomainSevDefPtr sev)
+{
+    if (!sev)
+        return;
+
+    virBufferAsprintf(buf, "<launch-security type='%s'>\n",
+                      virDomainLaunchSecurityTypeToString(sev->sectype));
+    virBufferAdjustIndent(buf, 2);
+
+    virBufferAsprintf(buf, "<cbitpos>%d</cbitpos>\n", sev->cbitpos);
+    virBufferAsprintf(buf, "<reduced-phys-bits>%d</reduced-phys-bits>\n",
+                      sev->reduced_phys_bits);
+    virBufferAsprintf(buf, "<policy>0x%04x</policy>\n", sev->policy);
+    if (sev->dh_cert)
+        virBufferEscapeString(buf, "<dh-cert>%s</dh-cert>\n", sev->dh_cert);
+
+    if (sev->session)
+        virBufferEscapeString(buf, "<session>%s</session>\n", sev->session);
+
+    virBufferAdjustIndent(buf, -2);
+    virBufferAddLit(buf, "</launch-security>\n");
+}
+
+
 static void
 virDomainPerfDefFormat(virBufferPtr buf, virDomainPerfDefPtr perf)
 {
@@ -27905,6 +28036,8 @@ virDomainDefFormatInternal(virDomainDefPtr def,
     if (def->keywrap)
         virDomainKeyWrapDefFormat(buf, def->keywrap);
 
+    virDomainSEVDefFormat(buf, def->sev);
+
     virBufferAdjustIndent(buf, -2);
     virBufferAddLit(buf, "</domain>\n");
 
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index a41cdce..fe7a6bb 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -142,6 +142,9 @@ typedef virDomainPanicDef *virDomainPanicDefPtr;
 typedef struct _virDomainMemoryDef virDomainMemoryDef;
 typedef virDomainMemoryDef *virDomainMemoryDefPtr;
 
+typedef struct _virDomainSevDef virDomainSevDef;
+typedef virDomainSevDef *virDomainSevDefPtr;
+
 /* forward declarations virDomainChrSourceDef, required by
  * virDomainNetDef
  */
@@ -2318,6 +2321,26 @@ struct _virDomainKeyWrapDef {
 };
 
 typedef enum {
+    VIR_DOMAIN_LAUNCH_SECURITY_NONE,
+    VIR_DOMAIN_LAUNCH_SECURITY_SEV,
+
+    VIR_DOMAIN_LAUNCH_SECURITY_LAST,
+} virDomainLaunchSecurity;
+
+typedef struct _virDomainSevDef virDomainSevDef;
+typedef virDomainSevDef *virDomainSevDefPtr;
+
+struct _virDomainSevDef {
+    int sectype; /* enum virDomainLaunchSecurity */
+    char *dh_cert;
+    char *session;
+    unsigned int policy;
+    unsigned int cbitpos;
+    unsigned int reduced_phys_bits;
+};
+
+
+typedef enum {
     VIR_DOMAIN_IOMMU_MODEL_INTEL,
 
     VIR_DOMAIN_IOMMU_MODEL_LAST
@@ -2508,6 +2531,9 @@ struct _virDomainDef {
 
     virDomainKeyWrapDefPtr keywrap;
 
+    /* SEV-specific domain */
+    virDomainSevDefPtr sev;
+
     /* Application-specific custom metadata */
     xmlNodePtr metadata;
 
@@ -3418,6 +3444,7 @@ VIR_ENUM_DECL(virDomainMemoryAllocation)
 VIR_ENUM_DECL(virDomainIOMMUModel)
 VIR_ENUM_DECL(virDomainVsockModel)
 VIR_ENUM_DECL(virDomainShmemModel)
+VIR_ENUM_DECL(virDomainLaunchSecurity)
 /* from libvirt.h */
 VIR_ENUM_DECL(virDomainState)
 VIR_ENUM_DECL(virDomainNostateReason)
diff --git a/tests/genericxml2xmlindata/launch-security-sev.xml b/tests/genericxml2xmlindata/launch-security-sev.xml
new file mode 100644
index 0000000..fb64e1e
--- /dev/null
+++ b/tests/genericxml2xmlindata/launch-security-sev.xml
@@ -0,0 +1,24 @@
+<domain type='kvm'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219100</memory>
+  <currentMemory unit='KiB'>219100</currentMemory>
+  <vcpu placement='static'>1</vcpu>
+  <os>
+    <type arch='x86_64' machine='pc-1.0'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+  </devices>
+  <launch-security type='sev'>
+    <cbitpos>47</cbitpos>
+    <reduced-phys-bits>1</reduced-phys-bits>
+    <policy>0x0001</policy>
+    <dh-cert>AQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAA</dh-cert>
+    <session>IHAVENOIDEABUTJUSTPROVIDINGASTRING</session>
+  </launch-security>
+</domain>
diff --git a/tests/genericxml2xmltest.c b/tests/genericxml2xmltest.c
index daad6e0..7a4fc1e 100644
--- a/tests/genericxml2xmltest.c
+++ b/tests/genericxml2xmltest.c
@@ -143,6 +143,8 @@ mymain(void)
 
     DO_TEST("tseg");
 
+    DO_TEST("launch-security-sev");
+
     virObjectUnref(caps);
     virObjectUnref(xmlopt);
 
-- 
2.7.4

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