On 03/12/2018 08:33 AM, Daniel P. Berrangé wrote:
On Thu, Mar 08, 2018 at 11:12:01AM -0600, Brijesh Singh wrote:
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 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@amd.com> --- docs/formatdomaincaps.html.in | 40 ++++++++++++++++++++++++++++++++++++++++ docs/schemas/domaincaps.rng | 20 ++++++++++++++++++++ src/conf/domain_capabilities.c | 20 ++++++++++++++++++++ src/conf/domain_capabilities.h | 1 + src/qemu/qemu_capabilities.c | 2 ++ 5 files changed, 83 insertions(+)
diff --git a/docs/formatdomaincaps.html.in b/docs/formatdomaincaps.html.in index 6bfcaf61caae..f38314166ac3 100644 --- a/docs/formatdomaincaps.html.in +++ b/docs/formatdomaincaps.html.in @@ -417,6 +417,12 @@ <value>3</value> </enum> </gic> + <sev> + <pdh> </pdh> + <cert-chain> </cert-chain> + <cbitpos> </cbitpos> + <reduced-phys-bits> </reduced-phys-bits> + </sev> </features> </domainCapabilities> </pre> @@ -441,5 +447,39 @@ <code>gic</code> element.</dd> </dl>
+ <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. + + For more details on SEV feature see: + <a href="https://support.amd.com/TechDocs/55766_SEV-KM%20API_Specification.pdf"> + SEV API spec</a> and <a href="http://amd-dev.wpengine.netdna-cdn.com/wordpress/media/2013/12/AMD_Memory_Encryption_Whitepaper_v7-Public.pdf"> + SEV White Paper</a> + + </p> + + <dl> + <dt><code>pdh</code></dt> + <dd>Platform diffie-hellman key, which can be exported to remote entities + which wish to establish a secure transport context with the SEV platform + in order to transmit data securely. The key is encoded in base64</dd> + <dt><code>cert-chain</code></dt> + <dd> Platform certificate chain -- which includes platform endorsement key + (PEK), owners certificate authory (OCA) and chip endorsement key (CEK). + The certificate chain is encoded in base64.</dd> + <dt><code>cbitpos</code></dt> + <dd>When memory encryption is enabled, one of the physical address bit + (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 loose certain bits in physical + address space. The number of bits we loose is hypervisor dependent.</dd> + </dl> + </body> </html> diff --git a/docs/schemas/domaincaps.rng b/docs/schemas/domaincaps.rng index 39053181eb9a..53b33eb83c1f 100644 --- a/docs/schemas/domaincaps.rng +++ b/docs/schemas/domaincaps.rng @@ -173,6 +173,9 @@ <element name='features'> <interleave> <ref name='gic'/> + <optional> + <ref name='sev'/> + </optional> </interleave> </element> </define> @@ -184,6 +187,23 @@ </element> </define>
+ <define name='sev'> + <element name='sev'> + <element name='pdh'> + <data type='string'/> + </element> + <element name='cert-chain'> + <data type='string'/> + </element> + <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 f7d9be50f82d..082065fb4733 100644 --- a/src/conf/domain_capabilities.c +++ b/src/conf/domain_capabilities.c @@ -549,6 +549,25 @@ 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); + virBufferAsprintf(buf, "<pdh>%s</pdh>\n", sev->pdh); + virBufferAsprintf(buf, "<cert-chain>%s</cert-chain>\n", + sev->cert_chain);
I wonder what length 'cert_chain' is going to be typically ? I hope we don't cause ourselves any trouble by having the data inline in the main capabilities XML ?
The PDH is 2K and cert-chain length is 8K. A quick google indicates that a maximum data length in XML can be up to 64000 bytes.