Re: [libvirt PATCH 3/3] conf: domain: sev: Make 'cbitpos' & 'reducedPhysBits' attrs optional

These XML attributes have been mandatory since the introduction of SEV support to libvirt. This design decision was based on QEMU's requirement for these to be mandatory for migration purposes, as differences in these values across platforms must result in the pre-migration checks failing (not that migration with SEV works at the time of this patch). Expecting the user to specify these is cumbersome and the same XML cannot be re-used across different revisions of SEV. Since we have SEV platform information saved in QEMU capabilities, we can make the attributes optional and should fill them in automatically in the QEMU driver right before starting it. Resolves: https://gitlab.com/libvirt/libvirt/-/issues/57 Signed-off-by: Erik Skultety <eskultet(a)redhat.com&gt; ---

docs/schemas/domaincommon.rng | 16 ++++--- src/conf/domain_conf.c | 46 ++++++++++++------- ...v-missing-platform-info.x86_64-2.12.0.args | 37 +++++++++++++++ ...nch-security-sev-missing-platform-info.xml | 35 ++++++++++++++ tests/qemuxml2argvtest.c | 1 + 5 files changed, 113 insertions(+), 22 deletions(-) create mode 100644 tests/qemuxml2argvdata/launch-security-sev-missing-platform-info.x86_64-2.12.0.args create mode 100644 tests/qemuxml2argvdata/launch-security-sev-missing-platform-info.xml diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng index 7d4b105981..9963fad4a6 100644 --- a/docs/schemas/domaincommon.rng +++ b/docs/schemas/domaincommon.rng @@ -467,12 +467,16 @@ <value>sev</value> </attribute> <interleave> - <element name="cbitpos"> - <data type="unsignedInt"/> - </element> - <element name="reducedPhysBits"> - <data type="unsignedInt"/> - </element> + <optional> + <element name="cbitpos"> + <data type="unsignedInt"/> + </element> + </optional> + <optional> + <element name="reducedPhysBits"> + <data type="unsignedInt"/> + </element> + </optional> <element name="policy"> <ref name="hexuint"/> </element> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 51efeb0e42..648a47ac84 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -16756,6 +16756,7 @@ virDomainSEVDefParseXML(xmlNodePtr sevNode, virDomainSEVDefPtr def; unsigned long policy; g_autofree char *type = NULL; + int rc = -1; def = g_new0(virDomainSEVDef, 1); @@ -16780,25 +16781,35 @@ virDomainSEVDefParseXML(xmlNodePtr sevNode, 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(./reducedPhysBits)", 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; } + /* the following attributes are platform dependent and if missing, we can + * autofill them from domain capabilities later + */ + rc = virXPathUInt("string(./cbitpos)", ctxt, &def->cbitpos); + if (rc == 0) { + def->haveCbitpos = VIR_TRISTATE_BOOL_YES; + } else if (rc == -2) { + virReportError(VIR_ERR_XML_ERROR, "%s", + _("Invalid format for launch security cbitpos")); + goto error; + } + + rc = virXPathUInt("string(./reducedPhysBits)", ctxt, + &def->reduced_phys_bits); + if (rc == 0) { + def->haveReducedPhysBits = VIR_TRISTATE_BOOL_YES; + } else if (rc == -2) { + virReportError(VIR_ERR_XML_ERROR, "%s", + _("Invalid format for launch security " + "reduced-phys-bits")); + goto error; + } + def->policy = policy; def->dh_cert = virXPathString("string(./dhCert)", ctxt); def->session = virXPathString("string(./session)", ctxt); @@ -28937,9 +28948,12 @@ virDomainSEVDefFormat(virBufferPtr buf, virDomainSEVDefPtr sev) virDomainLaunchSecurityTypeToString(sev->sectype)); virBufferAdjustIndent(buf, 2); - virBufferAsprintf(buf, "<cbitpos>%d</cbitpos>\n", sev->cbitpos); - virBufferAsprintf(buf, "<reducedPhysBits>%d</reducedPhysBits>\n", - sev->reduced_phys_bits); + if (sev->haveCbitpos) + virBufferAsprintf(buf, "<cbitpos>%d</cbitpos>\n", sev->cbitpos); + + if (sev->haveReducedPhysBits) + virBufferAsprintf(buf, "<reducedPhysBits>%d</reducedPhysBits>\n", + sev->reduced_phys_bits); virBufferAsprintf(buf, "<policy>0x%04x</policy>\n", sev->policy); if (sev->dh_cert) virBufferEscapeString(buf, "<dhCert>%s</dhCert>\n", sev->dh_cert); diff --git a/tests/qemuxml2argvdata/launch-security-sev-missing-platform-info.x86_64-2.12.0.args b/tests/qemuxml2argvdata/launch-security-sev-missing-platform-info.x86_64-2.12.0.args new file mode 100644 index 0000000000..378c3b681c --- /dev/null +++ b/tests/qemuxml2argvdata/launch-security-sev-missing-platform-info.x86_64-2.12.0.args @@ -0,0 +1,37 @@ +LC_ALL=C \ +PATH=/bin \ +HOME=/tmp/lib/domain--1-QEMUGuest1 \ +USER=test \ +LOGNAME=test \ +XDG_DATA_HOME=/tmp/lib/domain--1-QEMUGuest1/.local/share \ +XDG_CACHE_HOME=/tmp/lib/domain--1-QEMUGuest1/.cache \ +XDG_CONFIG_HOME=/tmp/lib/domain--1-QEMUGuest1/.config \ +QEMU_AUDIO_DRV=none \ +/usr/bin/qemu-system-x86_64 \ +-name guest=QEMUGuest1,debug-threads=on \ +-S \ +-object secret,id=masterKey0,format=raw,\ +file=/tmp/lib/domain--1-QEMUGuest1/master-key.aes \ +-machine pc-1.0,accel=kvm,usb=off,dump-guest-core=off,memory-encryption=sev0 \ +-m 214 \ +-realtime mlock=off \ +-smp 1,sockets=1,cores=1,threads=1 \ +-uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \ +-display none \ +-no-user-config \ +-nodefaults \ +-chardev socket,id=charmonitor,fd=1729,server,nowait \ +-mon chardev=charmonitor,id=monitor,mode=control \ +-rtc base=utc \ +-no-shutdown \ +-no-acpi \ +-boot strict=on \ +-device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 \ +-drive file=/dev/HostVG/QEMUGuest1,format=raw,if=none,id=drive-ide0-0-0 \ +-device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 \ +-object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1,policy=0x1,\ +dh-cert-file=/tmp/lib/domain--1-QEMUGuest1/dh_cert.base64,\ +session-file=/tmp/lib/domain--1-QEMUGuest1/session.base64 \ +-sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,\ +resourcecontrol=deny \ +-msg timestamp=on diff --git a/tests/qemuxml2argvdata/launch-security-sev-missing-platform-info.xml b/tests/qemuxml2argvdata/launch-security-sev-missing-platform-info.xml new file mode 100644 index 0000000000..41ec4cb872 --- /dev/null +++ b/tests/qemuxml2argvdata/launch-security-sev-missing-platform-info.xml @@ -0,0 +1,35 @@ +<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> + <emulator>/usr/bin/qemu-system-x86_64</emulator> + <disk type='block' device='disk'> + <driver name='qemu' type='raw'/> + <source dev='/dev/HostVG/QEMUGuest1'/> + <target dev='hda' bus='ide'/> + <address type='drive' controller='0' bus='0' target='0' unit='0'/> + </disk> + <controller type='usb' index='0'/> + <controller type='ide' index='0'/> + <controller type='pci' index='0' model='pci-root'/> + <input type='mouse' bus='ps2'/> + <input type='keyboard' bus='ps2'/> + <memballoon model='none'/> + </devices> + <launchSecurity type='sev'> + <policy>0x0001</policy> + <dhCert>AQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAAAQAAAAAOAAA</dhCert> + <session>IHAVENOIDEABUTJUSTPROVIDINGASTRING</session> + </launchSecurity> +</domain> diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c index 49567326d4..56247177e1 100644 --- a/tests/qemuxml2argvtest.c +++ b/tests/qemuxml2argvtest.c @@ -3314,6 +3314,7 @@ mymain(void) DO_TEST_CAPS_ARCH_LATEST("vhost-vsock-ccw-auto", "s390x"); DO_TEST_CAPS_VER("launch-security-sev", "2.12.0"); + DO_TEST_CAPS_VER("launch-security-sev-missing-platform-info", "2.12.0"); DO_TEST_CAPS_LATEST("vhost-user-fs-fd-memory"); DO_TEST_CAPS_LATEST("vhost-user-fs-hugepages");