[libvirt] [PATCH] Add new 'kvm' domain feature and ability to hide KVM signature
QEMU 2.1 added support for the kvm=off option to the -cpu command, allowing the KVM hypervisor signature to be hidden from the guest. This enables disabling of some paravirualization features in the guest as well as allowing certain drivers which test for the hypervisor to load. Domain XML syntax is as follows: <domain type='kvm> ... <features> ... <kvm> <hidden state='on'/> </kvm> </features> ... Signed-off-by: Alex Williamson <alex.williamson@redhat.com> --- If it's not obvious, this patch is derived from copying and modifying the similar hyperv feature support. Hopefully I've found all the right pieces. docs/formatdomain.html.in | 21 ++++ docs/schemas/domaincommon.rng | 18 +++- src/conf/domain_conf.c | 100 ++++++++++++++++++++ src/conf/domain_conf.h | 9 ++ src/qemu/qemu_command.c | 22 ++++ tests/qemuargv2xmltest.c | 2 .../qemuxml2argv-kvm-features-off.args | 5 + .../qemuxml2argv-kvm-features-off.xml | 27 +++++ .../qemuxml2argv-kvm-features.args | 5 + .../qemuxml2argvdata/qemuxml2argv-kvm-features.xml | 27 +++++ tests/qemuxml2argvtest.c | 3 + tests/qemuxml2xmltest.c | 3 + 12 files changed, 240 insertions(+), 2 deletions(-) create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.xml create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features.xml diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index bd99ae0..32cc381 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -1232,6 +1232,9 @@ <vapic state='on'/> <spinlocks state='on' retries='4096'/> </hyperv> + <kvm> + <hidden state='on'/> + </kvm> <pvspinlock/> </features> @@ -1310,7 +1313,23 @@ can be explicitly disabled by using <code>state='off'</code> attribute. </dd> - + <dt><code>kvm</code></dt> + <dd>Various features to change the behavior of the KVM hypervisor. + <table class="top_table"> + <tr> + <th>Feature</th> + <th>Description</th> + <th>Value</th> + <th>Since</th> + </tr> + <tr> + <td>hidden</td> + <td>Hide the KVM hypervisor from standard MSR based discovery</td> + <td> on, off</td> + <td><span class="since">2.1.0 (QEMU only)</span></td> + </tr> + </table> + </dd> </dl> <h3><a name="elementsTime">Time keeping</a></h3> diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng index 033f2f6..5c99a14 100644 --- a/docs/schemas/domaincommon.rng +++ b/docs/schemas/domaincommon.rng @@ -3826,7 +3826,7 @@ </define> <!-- A set of optional features: PAE, APIC, ACPI, - HyperV Enlightenment, paravirtual spinlocks and HAP support + HyperV Enlightenment, KVM features, paravirtual spinlocks and HAP support --> <define name="features"> <optional> @@ -3868,6 +3868,9 @@ </element> </optional> <optional> + <ref name="kvm"/> + </optional> + <optional> <element name="privnet"> <empty/> </element> @@ -4472,6 +4475,19 @@ </element> </define> + <!-- Optional KVM features --> + <define name="kvm"> + <element name="kvm"> + <interleave> + <optional> + <element name="hidden"> + <ref name="featurestate"/> + </element> + </optional> + </interleave> + </element> + </define> + <!-- Optional capabilities features --> <define name="capabilities"> <element name="capabilities"> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 934f6cb..8b0bdb0 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -142,6 +142,7 @@ VIR_ENUM_IMPL(virDomainFeature, VIR_DOMAIN_FEATURE_LAST, "viridian", "privnet", "hyperv", + "kvm", "pvspinlock", "capabilities") @@ -155,6 +156,9 @@ VIR_ENUM_IMPL(virDomainHyperv, VIR_DOMAIN_HYPERV_LAST, "vapic", "spinlocks") +VIR_ENUM_IMPL(virDomainKVM, VIR_DOMAIN_KVM_LAST, + "hidden") + VIR_ENUM_IMPL(virDomainCapsFeature, VIR_DOMAIN_CAPS_FEATURE_LAST, "audit_control", "audit_write", @@ -12168,6 +12172,7 @@ virDomainDefParseXML(xmlDocPtr xml, case VIR_DOMAIN_FEATURE_VIRIDIAN: case VIR_DOMAIN_FEATURE_PRIVNET: case VIR_DOMAIN_FEATURE_HYPERV: + case VIR_DOMAIN_FEATURE_KVM: def->features[val] = VIR_TRISTATE_SWITCH_ON; break; @@ -12295,6 +12300,54 @@ virDomainDefParseXML(xmlDocPtr xml, ctxt->node = node; } + if (def->features[VIR_DOMAIN_FEATURE_KVM] == VIR_TRISTATE_SWITCH_ON) { + int feature; + int value; + node = ctxt->node; + if ((n = virXPathNodeSet("./features/kvm/*", ctxt, &nodes)) < 0) + goto error; + + for (i = 0; i < n; i++) { + feature = virDomainKVMTypeFromString((const char *)nodes[i]->name); + if (feature < 0) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("unsupported KVM feature: %s"), + nodes[i]->name); + goto error; + } + + ctxt->node = nodes[i]; + + switch ((virDomainKVM) feature) { + case VIR_DOMAIN_KVM_HIDDEN: + if (!(tmp = virXPathString("string(./@state)", ctxt))) { + virReportError(VIR_ERR_XML_ERROR, + _("missing 'state' attribute for " + "KVM feature '%s'"), + nodes[i]->name); + goto error; + } + + if ((value = virTristateSwitchTypeFromString(tmp)) < 0) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("invalid value of state argument " + "for KVM feature '%s'"), + nodes[i]->name); + goto error; + } + + VIR_FREE(tmp); + def->kvm_features[feature] = value; + break; + + case VIR_DOMAIN_KVM_LAST: + break; + } + } + VIR_FREE(nodes); + ctxt->node = node; + } + if ((n = virXPathNodeSet("./features/capabilities/*", ctxt, &nodes)) < 0) goto error; @@ -14303,6 +14356,29 @@ virDomainDefFeaturesCheckABIStability(virDomainDefPtr src, } } + /* kvm */ + if (src->features[VIR_DOMAIN_FEATURE_KVM] == VIR_TRISTATE_SWITCH_ON) { + for (i = 0; i < VIR_DOMAIN_KVM_LAST; i++) { + switch ((virDomainKVM) i) { + case VIR_DOMAIN_KVM_HIDDEN: + if (src->kvm_features[i] != dst->kvm_features[i]) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("State of KVM feature '%s' differs: " + "source: '%s', destination: '%s'"), + virDomainKVMTypeToString(i), + virTristateSwitchTypeToString(src->kvm_features[i]), + virTristateSwitchTypeToString(dst->kvm_features[i])); + return false; + } + + break; + + case VIR_DOMAIN_KVM_LAST: + break; + } + } + } + return true; } @@ -18133,6 +18209,30 @@ virDomainDefFormatInternal(virDomainDefPtr def, virBufferAddLit(buf, "</hyperv>\n"); break; + case VIR_DOMAIN_FEATURE_KVM: + if (def->features[i] != VIR_TRISTATE_SWITCH_ON) + break; + + virBufferAddLit(buf, "<kvm>\n"); + virBufferAdjustIndent(buf, 2); + for (j = 0; j < VIR_DOMAIN_KVM_LAST; j++) { + switch ((virDomainKVM) j) { + case VIR_DOMAIN_KVM_HIDDEN: + if (def->kvm_features[j]) + virBufferAsprintf(buf, "<%s state='%s'/>\n", + virDomainKVMTypeToString(j), + virTristateSwitchTypeToString( + def->kvm_features[j])); + break; + + case VIR_DOMAIN_KVM_LAST: + break; + } + } + virBufferAdjustIndent(buf, -2); + virBufferAddLit(buf, "</kvm>\n"); + break; + case VIR_DOMAIN_FEATURE_CAPABILITIES: if (def->features[i] == VIR_DOMAIN_CAPABILITIES_POLICY_DEFAULT && !virDomainDefHasCapabilitiesFeatures(def)) diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index ff7d640..cca9c0f 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -1515,6 +1515,7 @@ typedef enum { VIR_DOMAIN_FEATURE_VIRIDIAN, VIR_DOMAIN_FEATURE_PRIVNET, VIR_DOMAIN_FEATURE_HYPERV, + VIR_DOMAIN_FEATURE_KVM, VIR_DOMAIN_FEATURE_PVSPINLOCK, VIR_DOMAIN_FEATURE_CAPABILITIES, @@ -1530,6 +1531,12 @@ typedef enum { } virDomainHyperv; typedef enum { + VIR_DOMAIN_KVM_HIDDEN = 0, + + VIR_DOMAIN_KVM_LAST +} virDomainKVM; + +typedef enum { VIR_DOMAIN_CAPABILITIES_POLICY_DEFAULT = 0, VIR_DOMAIN_CAPABILITIES_POLICY_ALLOW, VIR_DOMAIN_CAPABILITIES_POLICY_DENY, @@ -1943,6 +1950,7 @@ struct _virDomainDef { int features[VIR_DOMAIN_FEATURE_LAST]; int apic_eoi; int hyperv_features[VIR_DOMAIN_HYPERV_LAST]; + int kvm_features[VIR_DOMAIN_KVM_LAST]; unsigned int hyperv_spinlocks; /* These options are of type virTristateSwitch: ON = keep, OFF = drop */ @@ -2626,6 +2634,7 @@ VIR_ENUM_DECL(virDomainGraphicsSpiceStreamingMode) VIR_ENUM_DECL(virDomainGraphicsSpiceMouseMode) VIR_ENUM_DECL(virDomainGraphicsVNCSharePolicy) VIR_ENUM_DECL(virDomainHyperv) +VIR_ENUM_DECL(virDomainKVM) VIR_ENUM_DECL(virDomainRNGModel) VIR_ENUM_DECL(virDomainRNGBackend) VIR_ENUM_DECL(virDomainTPMModel) diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index 8a69976..77a84cc 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -6228,6 +6228,25 @@ qemuBuildCpuArgStr(virQEMUDriverPtr driver, } } + if (def->features[VIR_DOMAIN_FEATURE_KVM] == VIR_TRISTATE_SWITCH_ON) { + if (!have_cpu) { + virBufferAdd(&buf, default_model, -1); + have_cpu = true; + } + + for (i = 0; i < VIR_DOMAIN_KVM_LAST; i++) { + switch ((virDomainKVM) i) { + case VIR_DOMAIN_KVM_HIDDEN: + if (def->kvm_features[i] == VIR_TRISTATE_SWITCH_ON) + virBufferAsprintf(&buf, ",kvm=off"); + break; + + case VIR_DOMAIN_KVM_LAST: + break; + } + } + } + if (virBufferCheckError(&buf) < 0) goto cleanup; @@ -10692,6 +10711,9 @@ qemuParseCommandLineCPU(virDomainDefPtr dom, } virStringFreeList(hv_tokens); hv_tokens = NULL; + } else if (STREQ(tokens[i], "kvm=off")) { + dom->features[VIR_DOMAIN_FEATURE_KVM] = VIR_TRISTATE_SWITCH_ON; + dom->kvm_features[VIR_DOMAIN_KVM_HIDDEN] = VIR_TRISTATE_SWITCH_ON; } } diff --git a/tests/qemuargv2xmltest.c b/tests/qemuargv2xmltest.c index 6bad7d6..9c00cd9 100644 --- a/tests/qemuargv2xmltest.c +++ b/tests/qemuargv2xmltest.c @@ -284,6 +284,8 @@ mymain(void) DO_TEST("hyperv"); + DO_TEST("kvm-features"); + DO_TEST("pseries-nvram"); DO_TEST("pseries-disk"); diff --git a/tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.args b/tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.args new file mode 100644 index 0000000..363fd2a --- /dev/null +++ b/tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.args @@ -0,0 +1,5 @@ +LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \ +/usr/bin/qemu \ +-S -M pc -cpu qemu32 -m 214 -smp 6 -nographic \ +-monitor unix:/tmp/test-monitor,server,nowait \ +-boot n -usb -net none -serial none -parallel none diff --git a/tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.xml b/tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.xml new file mode 100644 index 0000000..64b8cd8 --- /dev/null +++ b/tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.xml @@ -0,0 +1,27 @@ +<domain type='qemu'> + <name>QEMUGuest1</name> + <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid> + <memory unit='KiB'>219100</memory> + <currentMemory unit='KiB'>219100</currentMemory> + <vcpu placement='static'>6</vcpu> + <os> + <type arch='i686' machine='pc'>hvm</type> + <boot dev='network'/> + </os> + <features> + <acpi/> + <kvm> + <hidden state='off'/> + </kvm> + </features> + <clock offset='utc'/> + <on_poweroff>destroy</on_poweroff> + <on_reboot>restart</on_reboot> + <on_crash>destroy</on_crash> + <devices> + <emulator>/usr/bin/qemu</emulator> + <controller type='usb' index='0'/> + <controller type='pci' index='0' model='pci-root'/> + <memballoon model='virtio'/> + </devices> +</domain> diff --git a/tests/qemuxml2argvdata/qemuxml2argv-kvm-features.args b/tests/qemuxml2argvdata/qemuxml2argv-kvm-features.args new file mode 100644 index 0000000..b223951 --- /dev/null +++ b/tests/qemuxml2argvdata/qemuxml2argv-kvm-features.args @@ -0,0 +1,5 @@ +LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test QEMU_AUDIO_DRV=none \ +/usr/bin/qemu -S -M pc \ +-cpu qemu32,kvm=off -m 214 -smp 6 -nographic -monitor \ +unix:/tmp/test-monitor,server,nowait -boot n -usb -net none -serial none \ +-parallel none diff --git a/tests/qemuxml2argvdata/qemuxml2argv-kvm-features.xml b/tests/qemuxml2argvdata/qemuxml2argv-kvm-features.xml new file mode 100644 index 0000000..3f2817e --- /dev/null +++ b/tests/qemuxml2argvdata/qemuxml2argv-kvm-features.xml @@ -0,0 +1,27 @@ +<domain type='qemu'> + <name>QEMUGuest1</name> + <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid> + <memory unit='KiB'>219100</memory> + <currentMemory unit='KiB'>219100</currentMemory> + <vcpu placement='static'>6</vcpu> + <os> + <type arch='i686' machine='pc'>hvm</type> + <boot dev='network'/> + </os> + <features> + <acpi/> + <kvm> + <hidden state='on'/> + </kvm> + </features> + <clock offset='utc'/> + <on_poweroff>destroy</on_poweroff> + <on_reboot>restart</on_reboot> + <on_crash>destroy</on_crash> + <devices> + <emulator>/usr/bin/qemu</emulator> + <controller type='usb' index='0'/> + <controller type='pci' index='0' model='pci-root'/> + <memballoon model='none'/> + </devices> +</domain> diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c index 62b969c..427ebfc 100644 --- a/tests/qemuxml2argvtest.c +++ b/tests/qemuxml2argvtest.c @@ -666,6 +666,9 @@ mymain(void) DO_TEST("hyperv", NONE); DO_TEST("hyperv-off", NONE); + DO_TEST("kvm-features", NONE); + DO_TEST("kvm-features-off", NONE); + DO_TEST("hugepages", QEMU_CAPS_MEM_PATH); DO_TEST("hugepages-pages", QEMU_CAPS_MEM_PATH, QEMU_CAPS_OBJECT_MEMORY_RAM, QEMU_CAPS_OBJECT_MEMORY_FILE); diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c index 5941323..3a174c0 100644 --- a/tests/qemuxml2xmltest.c +++ b/tests/qemuxml2xmltest.c @@ -196,6 +196,9 @@ mymain(void) DO_TEST("hyperv"); DO_TEST("hyperv-off"); + DO_TEST("kvm-features"); + DO_TEST("kvm-features-off"); + DO_TEST("hugepages"); DO_TEST("hugepages-pages"); DO_TEST("hugepages-pages2");
On 08/15/2014 12:32 PM, Alex Williamson wrote:
QEMU 2.1 added support for the kvm=off option to the -cpu command, allowing the KVM hypervisor signature to be hidden from the guest. This enables disabling of some paravirualization features in the guest as well as allowing certain drivers which test for the hypervisor to load. Domain XML syntax is as follows:
<domain type='kvm> ... <features> ... <kvm> <hidden state='on'/> </kvm> </features> ...
Signed-off-by: Alex Williamson <alex.williamson@redhat.com> ---
If it's not obvious, this patch is derived from copying and modifying the similar hyperv feature support. Hopefully I've found all the right pieces.
Seems to cover all the bases. couple minor bits:
docs/formatdomain.html.in | 21 ++++ docs/schemas/domaincommon.rng | 18 +++- src/conf/domain_conf.c | 100 ++++++++++++++++++++ src/conf/domain_conf.h | 9 ++ src/qemu/qemu_command.c | 22 ++++ tests/qemuargv2xmltest.c | 2 .../qemuxml2argv-kvm-features-off.args | 5 + .../qemuxml2argv-kvm-features-off.xml | 27 +++++ .../qemuxml2argv-kvm-features.args | 5 + .../qemuxml2argvdata/qemuxml2argv-kvm-features.xml | 27 +++++ tests/qemuxml2argvtest.c | 3 + tests/qemuxml2xmltest.c | 3 + 12 files changed, 240 insertions(+), 2 deletions(-) create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.xml create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features.xml
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index bd99ae0..32cc381 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -1232,6 +1232,9 @@ <vapic state='on'/> <spinlocks state='on' retries='4096'/> </hyperv> + <kvm> + <hidden state='on'/> + </kvm> <pvspinlock/>
</features> @@ -1310,7 +1313,23 @@ can be explicitly disabled by using <code>state='off'</code> attribute. </dd> - + <dt><code>kvm</code></dt> + <dd>Various features to change the behavior of the KVM hypervisor. + <table class="top_table"> + <tr> + <th>Feature</th> + <th>Description</th> + <th>Value</th> + <th>Since</th> + </tr> + <tr> + <td>hidden</td> + <td>Hide the KVM hypervisor from standard MSR based discovery</td> + <td> on, off</td> + <td><span class="since">2.1.0 (QEMU only)</span></td> + </tr> + </table> + </dd> </dl>
I'd specify that the default value is 'off' if using KVM, 'on' otherwise, and can be explicitly disabled with 'on'.
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index 8a69976..77a84cc 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -6228,6 +6228,25 @@ qemuBuildCpuArgStr(virQEMUDriverPtr driver, } }
+ if (def->features[VIR_DOMAIN_FEATURE_KVM] == VIR_TRISTATE_SWITCH_ON) { + if (!have_cpu) { + virBufferAdd(&buf, default_model, -1); + have_cpu = true; + } + + for (i = 0; i < VIR_DOMAIN_KVM_LAST; i++) { + switch ((virDomainKVM) i) { + case VIR_DOMAIN_KVM_HIDDEN: + if (def->kvm_features[i] == VIR_TRISTATE_SWITCH_ON) + virBufferAsprintf(&buf, ",kvm=off"); + break; +
There's a 'make syntax-check' warning here with latest git: src/qemu/qemu_command.c:6241: virBufferAsprintf(&buf, ",kvm=off"); maint.mk: use virBufferAddLit, not virBufferAsprintf, with a string literal make: *** [sc_prohibit_virBufferAsprintf_with_string_literal] Error 1 The rest looks fine, I'll commit v2 if no one has objections to the XML or code (CCing Peter and Jan who did some of the hyperv work) - Cole
On Tue, 2014-08-19 at 12:40 -0400, Cole Robinson wrote:
On 08/15/2014 12:32 PM, Alex Williamson wrote:
QEMU 2.1 added support for the kvm=off option to the -cpu command, allowing the KVM hypervisor signature to be hidden from the guest. This enables disabling of some paravirualization features in the guest as well as allowing certain drivers which test for the hypervisor to load. Domain XML syntax is as follows:
<domain type='kvm> ... <features> ... <kvm> <hidden state='on'/> </kvm> </features> ...
Signed-off-by: Alex Williamson <alex.williamson@redhat.com> ---
If it's not obvious, this patch is derived from copying and modifying the similar hyperv feature support. Hopefully I've found all the right pieces.
Seems to cover all the bases. couple minor bits:
docs/formatdomain.html.in | 21 ++++ docs/schemas/domaincommon.rng | 18 +++- src/conf/domain_conf.c | 100 ++++++++++++++++++++ src/conf/domain_conf.h | 9 ++ src/qemu/qemu_command.c | 22 ++++ tests/qemuargv2xmltest.c | 2 .../qemuxml2argv-kvm-features-off.args | 5 + .../qemuxml2argv-kvm-features-off.xml | 27 +++++ .../qemuxml2argv-kvm-features.args | 5 + .../qemuxml2argvdata/qemuxml2argv-kvm-features.xml | 27 +++++ tests/qemuxml2argvtest.c | 3 + tests/qemuxml2xmltest.c | 3 + 12 files changed, 240 insertions(+), 2 deletions(-) create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.xml create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features.xml
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index bd99ae0..32cc381 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -1232,6 +1232,9 @@ <vapic state='on'/> <spinlocks state='on' retries='4096'/> </hyperv> + <kvm> + <hidden state='on'/> + </kvm> <pvspinlock/>
</features> @@ -1310,7 +1313,23 @@ can be explicitly disabled by using <code>state='off'</code> attribute. </dd> - + <dt><code>kvm</code></dt> + <dd>Various features to change the behavior of the KVM hypervisor. + <table class="top_table"> + <tr> + <th>Feature</th> + <th>Description</th> + <th>Value</th> + <th>Since</th> + </tr> + <tr> + <td>hidden</td> + <td>Hide the KVM hypervisor from standard MSR based discovery</td> + <td> on, off</td> + <td><span class="since">2.1.0 (QEMU only)</span></td> + </tr> + </table> + </dd> </dl>
I'd specify that the default value is 'off' if using KVM, 'on' otherwise, and can be explicitly disabled with 'on'.
At the beginning of this section we specify: All features are listed within the features element, omitting a togglable feature tag turns it off. Our feature is whether to hide or not hide the KVM hypervisor signature. Note that 'not hide' does not imply expose, IMO. The default per the section scope is 'off'. Without KVM acceleration, there is no KVM hypervisor signature to hide, so the value is meaningless and QEMU accepts, but does not change behavior based on this. With KVM, there is of course a signature that can be hidden. Do you think there's still something to change here?
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index 8a69976..77a84cc 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -6228,6 +6228,25 @@ qemuBuildCpuArgStr(virQEMUDriverPtr driver, } }
+ if (def->features[VIR_DOMAIN_FEATURE_KVM] == VIR_TRISTATE_SWITCH_ON) { + if (!have_cpu) { + virBufferAdd(&buf, default_model, -1); + have_cpu = true; + } + + for (i = 0; i < VIR_DOMAIN_KVM_LAST; i++) { + switch ((virDomainKVM) i) { + case VIR_DOMAIN_KVM_HIDDEN: + if (def->kvm_features[i] == VIR_TRISTATE_SWITCH_ON) + virBufferAsprintf(&buf, ",kvm=off"); + break; +
There's a 'make syntax-check' warning here with latest git:
src/qemu/qemu_command.c:6241: virBufferAsprintf(&buf, ",kvm=off"); maint.mk: use virBufferAddLit, not virBufferAsprintf, with a string literal make: *** [sc_prohibit_virBufferAsprintf_with_string_literal] Error 1
The rest looks fine, I'll commit v2 if no one has objections to the XML or code (CCing Peter and Jan who did some of the hyperv work)
Ok, I'll make the switch. Thanks for the review, Alex
On 08/19/2014 03:36 PM, Alex Williamson wrote:
On Tue, 2014-08-19 at 12:40 -0400, Cole Robinson wrote:
On 08/15/2014 12:32 PM, Alex Williamson wrote:
QEMU 2.1 added support for the kvm=off option to the -cpu command, allowing the KVM hypervisor signature to be hidden from the guest. This enables disabling of some paravirualization features in the guest as well as allowing certain drivers which test for the hypervisor to load. Domain XML syntax is as follows:
<domain type='kvm> ... <features> ... <kvm> <hidden state='on'/> </kvm> </features> ...
Signed-off-by: Alex Williamson <alex.williamson@redhat.com> ---
If it's not obvious, this patch is derived from copying and modifying the similar hyperv feature support. Hopefully I've found all the right pieces.
Seems to cover all the bases. couple minor bits:
docs/formatdomain.html.in | 21 ++++ docs/schemas/domaincommon.rng | 18 +++- src/conf/domain_conf.c | 100 ++++++++++++++++++++ src/conf/domain_conf.h | 9 ++ src/qemu/qemu_command.c | 22 ++++ tests/qemuargv2xmltest.c | 2 .../qemuxml2argv-kvm-features-off.args | 5 + .../qemuxml2argv-kvm-features-off.xml | 27 +++++ .../qemuxml2argv-kvm-features.args | 5 + .../qemuxml2argvdata/qemuxml2argv-kvm-features.xml | 27 +++++ tests/qemuxml2argvtest.c | 3 + tests/qemuxml2xmltest.c | 3 + 12 files changed, 240 insertions(+), 2 deletions(-) create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features-off.xml create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-kvm-features.xml
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index bd99ae0..32cc381 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -1232,6 +1232,9 @@ <vapic state='on'/> <spinlocks state='on' retries='4096'/> </hyperv> + <kvm> + <hidden state='on'/> + </kvm> <pvspinlock/>
</features> @@ -1310,7 +1313,23 @@ can be explicitly disabled by using <code>state='off'</code> attribute. </dd> - + <dt><code>kvm</code></dt> + <dd>Various features to change the behavior of the KVM hypervisor. + <table class="top_table"> + <tr> + <th>Feature</th> + <th>Description</th> + <th>Value</th> + <th>Since</th> + </tr> + <tr> + <td>hidden</td> + <td>Hide the KVM hypervisor from standard MSR based discovery</td> + <td> on, off</td> + <td><span class="since">2.1.0 (QEMU only)</span></td> + </tr> + </table> + </dd> </dl>
I'd specify that the default value is 'off' if using KVM, 'on' otherwise, and can be explicitly disabled with 'on'.
At the beginning of this section we specify:
All features are listed within the features element, omitting a togglable feature tag turns it off.
Our feature is whether to hide or not hide the KVM hypervisor signature. Note that 'not hide' does not imply expose, IMO. The default per the section scope is 'off'. Without KVM acceleration, there is no KVM hypervisor signature to hide, so the value is meaningless and QEMU accepts, but does not change behavior based on this. With KVM, there is of course a signature that can be hidden.
Do you think there's still something to change here?
That's sufficient for me, thanks. - Cole
participants (2)
-
Alex Williamson -
Cole Robinson