[RFC PATCH 3/7] conf: introduce TrustDomain element in domain
Pavel Hrdina
phrdina at redhat.com
Fri Jun 18 12:08:48 UTC 2021
On Fri, Jun 18, 2021 at 04:50:48PM +0800, Zhenzhong Duan wrote:
> The TrustDomain element can be used to define the security model to
> use when launching a domain. Only type 'tdx' is supported currently.
>
> When 'tdx' is used, the VM will launched with Intel TDX feature enabled.
> TDX feature supports running encrypted VM (Trust Domain, TD) under the
> control of KVM. A TD runs in a CPU model which protects the
> confidentiality of its memory and its CPU state from other software
>
> There is a child element 'policy' in TrustDomain. In 'policy', bit 0
> is used to enable TDX debug, other bits are reserved currently.
>
> For example:
>
> <TrustDomain type='tdx'>
> <policy>0x0001</policy>
> </TrustDomain>
Any reason why you are adding a new element that basically copies
exactly what <launchSecurity> is doing?
In libvirt it will essentially use `confidential-guest-support` which is
used for launchSecurity so there is no need to duplicate the code and
the XML element.
It could look like this:
<launchSecurity type='tdx'>
<policy>0x0001</policy>
</launchSecurity>
We would have to reorganize the <launchSecurity> documentation a little
bit but otherwise there is nothing blocking us to have single element to
specify different type of encrypted/confidential/secure/... VMs.
We already have patches for similar feature for s390 which will also
reuse this element and in the future any other CPU architecture can
reuse it.
Pavel
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan at intel.com>
> ---
> docs/schemas/domaincommon.rng | 16 ++++
> src/conf/domain_conf.c | 84 +++++++++++++++++++
> src/conf/domain_conf.h | 15 ++++
> src/conf/virconftypes.h | 2 +
> src/qemu/qemu_validate.c | 8 ++
> .../genericxml2xmlindata/trust-domain-tdx.xml | 21 +++++
> tests/genericxml2xmltest.c | 1 +
> 7 files changed, 147 insertions(+)
> create mode 100644 tests/genericxml2xmlindata/trust-domain-tdx.xml
>
> diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
> index 5ea14b6dbf..2b39a01e84 100644
> --- a/docs/schemas/domaincommon.rng
> +++ b/docs/schemas/domaincommon.rng
> @@ -89,6 +89,9 @@
> <optional>
> <ref name="launchSecurity"/>
> </optional>
> + <optional>
> + <ref name="TrustDomain"/>
> + </optional>
> <optional>
> <ref name="bhyvecmdline"/>
> </optional>
> @@ -518,6 +521,19 @@
> </element>
> </define>
>
> + <define name="TrustDomain">
> + <element name="TrustDomain">
> + <attribute name="type">
> + <value>tdx</value>
> + </attribute>
> + <interleave>
> + <element name="policy">
> + <ref name="hexuint"/>
> + </element>
> + </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 139cdfc0a7..a51db088c1 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -1403,6 +1403,12 @@ VIR_ENUM_IMPL(virDomainLaunchSecurity,
> "sev",
> );
>
> +VIR_ENUM_IMPL(virDomainTrustDomain,
> + VIR_DOMAIN_TRUST_DOMAIN_LAST,
> + "",
> + "tdx",
> +);
> +
> static virClass *virDomainObjClass;
> static virClass *virDomainXMLOptionClass;
> static void virDomainObjDispose(void *obj);
> @@ -3502,6 +3508,16 @@ virDomainSEVDefFree(virDomainSEVDef *def)
> g_free(def);
> }
>
> +
> +static void
> +virDomainTDXDefFree(virDomainTDXDef *def)
> +{
> + if (!def)
> + return;
> +
> + g_free(def);
> +}
> +
> static void
> virDomainOSDefClear(virDomainOSDef *os)
> {
> @@ -3704,6 +3720,7 @@ void virDomainDefFree(virDomainDef *def)
> (def->ns.free)(def->namespaceData);
>
> virDomainSEVDefFree(def->sev);
> + virDomainTDXDefFree(def->tdx);
>
> xmlFreeNode(def->metadata);
>
> @@ -14793,6 +14810,53 @@ virDomainSEVDefParseXML(xmlNodePtr sevNode,
> return NULL;
> }
>
> +static virDomainTDXDef *
> +virDomainTDXDefParseXML(xmlNodePtr tdxNode,
> + xmlXPathContextPtr ctxt)
> +{
> + VIR_XPATH_NODE_AUTORESTORE(ctxt)
> + virDomainTDXDef *def;
> + unsigned long policy;
> + g_autofree char *type = NULL;
> +
> + def = g_new0(virDomainTDXDef, 1);
> +
> + ctxt->node = tdxNode;
> +
> + if (!(type = virXMLPropString(tdxNode, "type"))) {
> + virReportError(VIR_ERR_XML_ERROR, "%s",
> + _("missing trust domain type"));
> + goto error;
> + }
> +
> + def->sectype = virDomainTrustDomainTypeFromString(type);
> + switch ((virDomainTrustDomain) def->sectype) {
> + case VIR_DOMAIN_TRUST_DOMAIN_TDX:
> + break;
> + case VIR_DOMAIN_TRUST_DOMAIN_NONE:
> + case VIR_DOMAIN_TRUST_DOMAIN_LAST:
> + default:
> + virReportError(VIR_ERR_XML_ERROR,
> + _("unsupported trust domain type '%s'"),
> + type);
> + goto error;
> + }
> +
> + if (virXPathULongHex("string(./policy)", ctxt, &policy) < 0) {
> + virReportError(VIR_ERR_XML_ERROR, "%s",
> + _("failed to get trust domain policy"));
> + goto error;
> + }
> +
> + def->policy = policy;
> +
> + return def;
> +
> + error:
> + virDomainTDXDefFree(def);
> + return NULL;
> +}
> +
>
> static virDomainMemoryDef *
> virDomainMemoryDefParseXML(virDomainXMLOption *xmlopt,
> @@ -20117,6 +20181,13 @@ virDomainDefParseXML(xmlDocPtr xml,
> goto error;
> }
>
> + /* Check for TDX feature */
> + if ((node = virXPathNode("./TrustDomain", ctxt)) != NULL) {
> + def->tdx = virDomainTDXDefParseXML(node, ctxt);
> + if (!def->tdx)
> + goto error;
> + }
> +
> /* analysis of memory devices */
> if ((n = virXPathNodeSet("./devices/memory", ctxt, &nodes)) < 0)
> goto error;
> @@ -26870,6 +26941,18 @@ virDomainSEVDefFormat(virBuffer *buf, virDomainSEVDef *sev)
> virBufferAddLit(buf, "</launchSecurity>\n");
> }
>
> +static void
> +virDomainTDXDefFormat(virBuffer *buf, virDomainTDXDef *tdx)
> +{
> + if (!tdx)
> + return;
> +
> + virBufferAsprintf(buf, "<TrustDomain type='tdx'>\n");
> + virBufferAdjustIndent(buf, 2);
> + virBufferAsprintf(buf, "<policy>0x%04x</policy>\n", tdx->policy);
> + virBufferAdjustIndent(buf, -2);
> + virBufferAddLit(buf, "</TrustDomain>\n");
> +}
>
> static void
> virDomainPerfDefFormat(virBuffer *buf, virDomainPerfDef *perf)
> @@ -28277,6 +28360,7 @@ virDomainDefFormatInternalSetRootName(virDomainDef *def,
> virDomainKeyWrapDefFormat(buf, def->keywrap);
>
> virDomainSEVDefFormat(buf, def->sev);
> + virDomainTDXDefFormat(buf, def->tdx);
>
> if (def->namespaceData && def->ns.format) {
> if ((def->ns.format)(buf, def->namespaceData) < 0)
> diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
> index f706c498ff..7cb5061c8c 100644
> --- a/src/conf/domain_conf.h
> +++ b/src/conf/domain_conf.h
> @@ -2661,6 +2661,17 @@ struct _virDomainSEVDef {
> unsigned int reduced_phys_bits;
> };
>
> +typedef enum {
> + VIR_DOMAIN_TRUST_DOMAIN_NONE,
> + VIR_DOMAIN_TRUST_DOMAIN_TDX,
> +
> + VIR_DOMAIN_TRUST_DOMAIN_LAST,
> +} virDomainTrustDomain;
> +
> +struct _virDomainTDXDef {
> + int sectype; /* enum virDomainTrustDomain */
> + unsigned int policy; /* bit 0 set hint debug enabled, other bit reserved */
> +};
>
> typedef enum {
> VIR_DOMAIN_IOMMU_MODEL_INTEL,
> @@ -2874,6 +2885,9 @@ struct _virDomainDef {
> /* SEV-specific domain */
> virDomainSEVDef *sev;
>
> + /* TDX-specific domain */
> + virDomainTDXDef *tdx;
> +
> /* Application-specific custom metadata */
> xmlNodePtr metadata;
>
> @@ -3888,6 +3902,7 @@ VIR_ENUM_DECL(virDomainVsockModel);
> VIR_ENUM_DECL(virDomainShmemModel);
> VIR_ENUM_DECL(virDomainShmemRole);
> VIR_ENUM_DECL(virDomainLaunchSecurity);
> +VIR_ENUM_DECL(virDomainTrustDomain);
> /* from libvirt.h */
> VIR_ENUM_DECL(virDomainState);
> VIR_ENUM_DECL(virDomainNostateReason);
> diff --git a/src/conf/virconftypes.h b/src/conf/virconftypes.h
> index b21068486e..dbd2eb984c 100644
> --- a/src/conf/virconftypes.h
> +++ b/src/conf/virconftypes.h
> @@ -202,6 +202,8 @@ typedef struct _virDomainResourceDef virDomainResourceDef;
>
> typedef struct _virDomainSEVDef virDomainSEVDef;
>
> +typedef struct _virDomainTDXDef virDomainTDXDef;
> +
> typedef struct _virDomainShmemDef virDomainShmemDef;
>
> typedef struct _virDomainSmartcardDef virDomainSmartcardDef;
> diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c
> index 382473d03b..2efd011cc0 100644
> --- a/src/qemu/qemu_validate.c
> +++ b/src/qemu/qemu_validate.c
> @@ -1222,6 +1222,14 @@ qemuValidateDomainDef(const virDomainDef *def,
> return -1;
> }
>
> + if (def->tdx &&
> + !virQEMUCapsGet(qemuCaps, QEMU_CAPS_TDX_GUEST)) {
> + virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
> + _("TDX trust domain is not supported with "
> + "this QEMU binary"));
> + return -1;
> + }
> +
> if (def->naudios > 1 &&
> !virQEMUCapsGet(qemuCaps, QEMU_CAPS_AUDIODEV)) {
> virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> diff --git a/tests/genericxml2xmlindata/trust-domain-tdx.xml b/tests/genericxml2xmlindata/trust-domain-tdx.xml
> new file mode 100644
> index 0000000000..7a56cf0e92
> --- /dev/null
> +++ b/tests/genericxml2xmlindata/trust-domain-tdx.xml
> @@ -0,0 +1,21 @@
> +<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>
> + <TrustDomain type='tdx'>
> + <policy>0x0001</policy>
> + </TrustDomain>
> +</domain>
> +
> diff --git a/tests/genericxml2xmltest.c b/tests/genericxml2xmltest.c
> index ac89422a32..0bd7717953 100644
> --- a/tests/genericxml2xmltest.c
> +++ b/tests/genericxml2xmltest.c
> @@ -233,6 +233,7 @@ mymain(void)
> DO_TEST("tseg");
>
> DO_TEST("launch-security-sev");
> + DO_TEST("trust-domain-tdx");
>
> DO_TEST_DIFFERENT("cputune");
> DO_TEST("device-backenddomain");
> --
> 2.25.1
>
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