[libvirt] [PATCH v7 2/9] conf: expose SEV feature in domain capabilities

Extend hypervisor capabilities to include sev feature. When available, hypervisor supports launching an encrypted VM on AMD platform. The sev feature tag provides additional details like Platform Diffie-Hellman (PDH) key and certificate chain which can be used by the guest owner to establish a cryptographic session with the SEV firmware to negotiate keys used for attestation or to provide secret during launch. Signed-off-by: Brijesh Singh <brijesh.singh(a)amd.com&gt; --- docs/formatdomaincaps.html.in | 30 ++++++++++++++++++++++++++ docs/schemas/domaincaps.rng | 14 ++++++++++++ src/conf/domain_capabilities.c | 19 ++++++++++++++++- src/conf/domain_capabilities.h | 1 + src/qemu/qemu_capabilities.c | 48 +++++++++++++++++++++++++++++++++++++++++- 5 files changed, 110 insertions(+), 2 deletions(-) diff --git a/docs/formatdomaincaps.html.in b/docs/formatdomaincaps.html.in index e0814cb..6be553a 100644 --- a/docs/formatdomaincaps.html.in +++ b/docs/formatdomaincaps.html.in @@ -435,6 +435,10 @@ &lt;/gic&gt; &lt;vmcoreinfo supported='yes'/&gt; &lt;genid supported='yes'/&gt; + &lt;sev&gt; + &lt;cbitpos&gt;47&lt;/cbitpos&gt; + &lt;reduced-phys-bits&gt;1&lt;/reduced-phys-bits&gt; + &lt;/sev&gt; &lt;/features&gt; &lt;/domainCapabilities&gt; </pre> @@ -467,5 +471,31 @@ <p>Reports whether the genid feature can be used by the domain.</p> + <h4><a id="elementsSEV">SEV capabilities</a></h4> + + <p>AMD Secure Encrypted Virtualization (SEV) capabilities are exposed under + the <code>sev</code> element. + SEV is an extension to the AMD-V architecture which supports running + virtual machines (VMs) under the control of a hypervisor. When supported, + guest owner can create a VM whose memory contents will be transparently + encrypted with a key unique to that VM.</p> + + <p> + For more details on SEV feature see: + <a href="https://support.amd.com/TechDocs/55766_SEV-KM%20API_Specificat... + SEV API spec</a> and <a href="http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2013/12... + SEV White Paper</a> + </p> + + <dl> + <dt><code>cbitpos</code></dt> + <dd>When memory encryption is enabled, one of the physical address bits + (aka the C-bit) is utilized to mark if a memory page is protected. The + C-bit position is Hypervisor dependent.</dd> + <dt><code>reduced-phys-bits</code></dt> + <dd>When memory encryption is enabled, we lose certain bits in physical + address space. The number of bits we lose is hypervisor dependent.</dd> + </dl> + </body> </html> diff --git a/docs/schemas/domaincaps.rng b/docs/schemas/domaincaps.rng index 5ceabb0..1d0a2e1 100644 --- a/docs/schemas/domaincaps.rng +++ b/docs/schemas/domaincaps.rng @@ -185,6 +185,9 @@ <ref name='gic'/> <ref name='vmcoreinfo'/> <ref name='vmgenid'/> + <optional> + <ref name='sev'/> + </optional> </interleave> </element> </define> @@ -208,6 +211,17 @@ </element> </define> + <define name='sev'> + <element name='sev'> + <element name='cbitpos'> + <data type='unsignedInt'/> + </element> + <element name='reduced-phys-bits'> + <data type='unsignedInt'/> + </element> + </element> + </define> + <define name='value'> <zeroOrMore> <element name='value'> diff --git a/src/conf/domain_capabilities.c b/src/conf/domain_capabilities.c index 3589777..54b0878 100644 --- a/src/conf/domain_capabilities.c +++ b/src/conf/domain_capabilities.c @@ -88,6 +88,7 @@ virDomainCapsDispose(void *obj) VIR_FREE(caps->machine); virObjectUnref(caps->cpu.custom); virCPUDefFree(caps->cpu.hostModel); + virSEVCapabilitiesFree(caps->sev); virDomainCapsStringValuesFree(&caps->os.loader.values); } @@ -554,6 +555,22 @@ virDomainCapsFeatureGICFormat(virBufferPtr buf, FORMAT_EPILOGUE(gic); } +static void +virDomainCapsFeatureSEVFormat(virBufferPtr buf, + virSEVCapabilityPtr const sev) +{ + if (!sev) + return; + + virBufferAddLit(buf, "<sev supported='yes'>\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); + virBufferAdjustIndent(buf, -2); + virBufferAddLit(buf, "</sev>\n"); +} + char * virDomainCapsFormat(virDomainCapsPtr const caps) @@ -597,9 +614,9 @@ virDomainCapsFormat(virDomainCapsPtr const caps) virDomainCapsFeatureGICFormat(&buf, &caps->gic); virBufferAsprintf(&buf, "<vmcoreinfo supported='%s'/>\n", caps->vmcoreinfo ? "yes" : "no"); - virBufferAsprintf(&buf, "<genid supported='%s'/>\n", caps->genid ? "yes" : "no"); + virDomainCapsFeatureSEVFormat(&buf, caps->sev); virBufferAdjustIndent(&buf, -2); virBufferAddLit(&buf, "</features>\n"); diff --git a/src/conf/domain_capabilities.h b/src/conf/domain_capabilities.h index 30b3272..17c1f1c 100644 --- a/src/conf/domain_capabilities.h +++ b/src/conf/domain_capabilities.h @@ -176,6 +176,7 @@ struct _virDomainCaps { virDomainCapsFeatureGIC gic; bool vmcoreinfo; bool genid; + virSEVCapabilityPtr sev; /* add new domain features here */ }; diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c index 2c3665d..5db444c 100644 --- a/src/qemu/qemu_capabilities.c +++ b/src/qemu/qemu_capabilities.c @@ -5145,6 +5145,50 @@ virQEMUCapsFillDomainFeatureGICCaps(virQEMUCapsPtr qemuCaps, } +/** + * virQEMUCapsFillDomainFeatureSEVCaps: + * @qemuCaps: QEMU capabilities + * @domCaps: domain capabilities + * + * Take the information about SEV capabilities that has been obtained + * using the 'query-sev-capabilities' QMP command and stored in @qemuCaps + * and convert it to a form suitable for @domCaps. + * + * Returns: 0 on success, <0 on failure + */ +static int +virQEMUCapsFillDomainFeatureSEVCaps(virQEMUCapsPtr qemuCaps, + virDomainCapsPtr domCaps) +{ + virSEVCapability *sev; + virSEVCapability *cap = qemuCaps->sevCapabilities; + + if (!cap) + return 0; + + if (VIR_ALLOC(sev) < 0) + return -1; + + if (VIR_STRDUP(sev->pdh, cap->pdh) < 0) + goto out; + + if (VIR_STRDUP(sev->cert_chain, cap->cert_chain) < 0) + goto out; + + sev->cbitpos = cap->cbitpos; + sev->reduced_phys_bits = cap->reduced_phys_bits; + domCaps->sev = sev; + + return 0; + + out: + VIR_FREE(sev->cert_chain); + VIR_FREE(sev->pdh); + VIR_FREE(sev); + return -1; +} + + int virQEMUCapsFillDomainCaps(virCapsPtr caps, virDomainCapsPtr domCaps, @@ -5182,8 +5226,10 @@ virQEMUCapsFillDomainCaps(virCapsPtr caps, virQEMUCapsFillDomainDeviceGraphicsCaps(qemuCaps, graphics) < 0 || virQEMUCapsFillDomainDeviceVideoCaps(qemuCaps, video) < 0 || virQEMUCapsFillDomainDeviceHostdevCaps(qemuCaps, hostdev) < 0 || - virQEMUCapsFillDomainFeatureGICCaps(qemuCaps, domCaps) < 0) + virQEMUCapsFillDomainFeatureGICCaps(qemuCaps, domCaps) < 0 || + virQEMUCapsFillDomainFeatureSEVCaps(qemuCaps, domCaps) < 0) return -1; + return 0; } -- 2.7.4