Re: [libvirt] [PATCH v2 3/9] conf: introduce launch-security element in domain

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(a)amd.com&gt; --- docs/formatdomain.html.in | 120 ++++++++++++++++++++++++++++++++++++++++++ docs/schemas/domaincommon.rng | 39 ++++++++++++++ src/conf/domain_conf.c | 111 ++++++++++++++++++++++++++++++++++++++ src/conf/domain_conf.h | 27 ++++++++++ 4 files changed, 297 insertions(+) diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index 6fd2189cd2f4..830d2a3c59be 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -8195,6 +8195,126 @@ 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 SEV API spec + <a href="https://support.amd.com/TechDocs/55766_SEV-KM%20API_Specificat... https://support.amd.com/TechDocs/55766_SEV-KM%20API_Specification.pdf </a> + <span class="since">Since 4.2.0</span> + </p> + <pre> +&lt;domain&gt; + ... + &lt;launch-security type='sev'&gt; + &lt;policy&gt; 0 &lt;/policy&gt; + &lt;cbitpos&gt; 47 &lt;/cbitpos&gt; + &lt;reduced-phys-bits&gt; 5 &lt;/reduced-phys-bits&gt; + &lt;session&gt; ... &lt;/session&gt; + &lt;dh-cert&gt; ... &lt;/dh&gt; + &lt;/sev&gt; + ... +&lt;/domain&gt; +</pre> + + <p> + A least <code>cbitpos</code> and <code>reduced-phys-bits</code> must be + nested within the <code>launch-security</code> element. + </p> + <dl> + <dt><code>cbitpos</code></dt> + <dd>The <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 domaincapabilities. + </dd> + <dt><code>reduced-phys-bits</code></dt> + <dd>The <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 domaincapabilities. + </dd> + <dt><code>policy</code></dt> + <dd>The optional <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-byte structure 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> 15:6 </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> + Default value is 0x1 + + </dd> + <dt><code>dh-cert</code></dt> + <dd>The optional <code>dh-cert</code> element provides the guest owners public + 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. The value must be encoded in base64. + </dd> + <dt><code>session</code></dt> + <dd>The optional <code>session</code> element provides the guest owners + session blob defined in SEV API spec. The value must be encoded in base64. + + See SEV spec LAUNCH_START section for 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 8165e699d67e..e3dcc69067c2 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 +439,42 @@ </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> + <optional> + <element name="policy"> + <ref name='hexuint'/> + </element> + </optional> + <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 fcafc8b2fafe..52d34de69d45 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -929,6 +929,10 @@ 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); @@ -2897,6 +2901,14 @@ virDomainCachetuneDefFree(virDomainCachetuneDefPtr cachetune) VIR_FREE(cachetune); } +static void +virDomainSevDefFree(virDomainSevDefPtr def) +{ + VIR_FREE(def->dh_cert); + VIR_FREE(def->session); + + VIR_FREE(def); +} void virDomainDefFree(virDomainDefPtr def) { @@ -3079,6 +3091,9 @@ void virDomainDefFree(virDomainDefPtr def) if (def->namespaceData && def->ns.free) (def->ns.free)(def->namespaceData); + if (def->sev) + virDomainSevDefFree(def->sev); + xmlFreeNode(def->metadata); VIR_FREE(def); @@ -15539,6 +15554,71 @@ virDomainMemoryTargetDefParseXML(xmlNodePtr node, return ret; } +static virDomainSevDefPtr +virDomainSevDefParseXML(xmlNodePtr sevNode, + xmlXPathContextPtr ctxt) +{ + char *tmp = NULL, *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; + } + + if (virDomainLaunchSecurityTypeFromString(type) != + VIR_DOMAIN_LAUNCH_SECURITY_SEV) { + goto error; + } + + if (virXPathInt("string(./cbitpos)", ctxt, &def->cbitpos) < 0) { + virReportError(VIR_ERR_XML_ERROR, "%s", _("failed to get cbitpos")); + goto error; + } + + if (virXPathInt("string(./reduced-phys-bits)", ctxt, + &def->reduced_phys_bits) < 0) { + virReportError(VIR_ERR_XML_ERROR, "%s", + _("failed to get reduced-phys-bits")); + goto error; + } + + if (virXPathULongHex("string(./policy)", ctxt, &policy) < 0) + policy = 0x1; + + 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, @@ -20212,6 +20292,13 @@ 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; @@ -26102,6 +26189,27 @@ virDomainKeyWrapDefFormat(virBufferPtr buf, virDomainKeyWrapDefPtr keywrap) virBufferAddLit(buf, "</keywrap>\n"); } +static void +virDomainSevDefFormat(virBufferPtr buf, virDomainSevDefPtr sev) +{ + virBufferAddLit(buf, "<launch-security type='sev'>\n"); + 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>%d</policy>\n", sev->policy); + if (sev->dh_cert) + virBufferAsprintf(buf, "<dh_cert>%s</dh_cert>\n", sev->dh_cert); + + if (sev->session) + virBufferAsprintf(buf, "<session>%s</session>\n", sev->session); + + virBufferAdjustIndent(buf, -2); + virBufferAddLit(buf, "</launch-security>\n"); +} + + static void virDomainPerfDefFormat(virBufferPtr buf, virDomainPerfDefPtr perf) { @@ -27274,6 +27382,9 @@ virDomainDefFormatInternal(virDomainDefPtr def, if (def->keywrap) virDomainKeyWrapDefFormat(buf, def->keywrap); + if (def->sev) + 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 368f16f3fbf9..ff625a0aff1b 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 */ @@ -2289,6 +2292,26 @@ struct _virDomainKeyWrapDef { int dea; /* enum virTristateSwitch */ }; +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 { + char *dh_cert; + char *session; + char *configDir; + int policy; + int cbitpos; + int reduced_phys_bits; +};