[libvirt] [PATCH 1/2] Introduce GIC feature
John Ferlan
jferlan at redhat.com
Wed Apr 29 11:31:55 UTC 2015
On 04/27/2015 09:07 AM, Michal Privoznik wrote:
> Some platforms, like aarch64, don't have APIC but GIC. So there's
> no reason to have <apic/> feature turned on. However, we are
s/have/have the/
s/turned on/enabled/
> still missing <gic/> feature. This commit introduces the feature
> to XML parser and formatter, adds documentation and updates RNG
s/to/to the/
> schema.
>
> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> ---
> docs/formatdomain.html.in | 9 +++++++++
> docs/schemas/domaincommon.rng | 11 ++++++++++-
> src/conf/domain_conf.c | 34 +++++++++++++++++++++++++++++++++-
> src/conf/domain_conf.h | 2 ++
> 4 files changed, 54 insertions(+), 2 deletions(-)
>
Does aarch64 just ignore APIC? Makes me wonder how things work today...
Is this also an architecture capability feature that needs to be added?
IOW: How does one determine whether their architecture has GIC instead
of APIC.
> diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
> index e921749..27883fe 100644
> --- a/docs/formatdomain.html.in
> +++ b/docs/formatdomain.html.in
> @@ -1401,6 +1401,7 @@
> <hidden state='on'/>
> </kvm>
> <pvspinlock/>
> + <gic version='2'/>
>
> </features>
> ...</pre>
> @@ -1501,6 +1502,14 @@
> performance monitoring unit for the guest.
> <span class="since">Since 1.2.12</span>
> </dd>
> + <dt><code>gic</code></dt>
> + <dd>Some architectures don't have <code>APIC</code> but have
> + <code>GIC</code> <i>(Generic Interrupt Controller)</i>. For example
> + aarch64 is one of those architectures. If the guest belongs to the
> + set, you may want to turn on this feature instead of
> + <code>APIC</code>. Optional attribute <code>version</code> specifies
> + version of the controller, however may not be supported by all
> + hypervisors.</dd>
Enable for architectures using a General Interrupt Controller instead of
APIC in order to handle interrupts. For example, the 'aarch64'
architecture uses <code>gic</code> instead of <code>apic</code>. The
optional attribute <code>version</code> specifies the GIC version;
however, it may not be supported by all hypervisors. <span
class="since">Since 1.2.16</span>
</dd>
NOTE1: I didn't put <code> </code> around the capitalized GIC or APIC
since to me that would infer the feature must be capitalized.
NOTE2: That last sentance is awkward - what would happen if it were
supplied, but the hypervisor didn't support/recognize it?
NOTE3: I added the <span> and put the </dd> on a separate line like the
previous <dd>...</dd> - not that it matters.
> </dl>
>
> <h3><a name="elementsTime">Time keeping</a></h3>
> diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
> index 19461f5..b1d6f6b 100644
> --- a/docs/schemas/domaincommon.rng
> +++ b/docs/schemas/domaincommon.rng
> @@ -3953,7 +3953,7 @@
> </element>
> </define>
> <!--
> - A set of optional features: PAE, APIC, ACPI,
> + A set of optional features: PAE, APIC, ACPI, GIC,
> HyperV Enlightenment, KVM features, paravirtual spinlocks and HAP support
> -->
> <define name="features">
> @@ -4014,6 +4014,15 @@
> <optional>
> <ref name="pmu"/>
> </optional>
> + <optional>
> + <element name="gic">
> + <optional>
> + <attribute name="version">
> + <ref name="positiveInteger"/>
> + </attribute>
> + </optional>
> + </element>
> + </optional>
> </interleave>
> </element>
> </optional>
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 03710cb..466163e 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -144,7 +144,8 @@ VIR_ENUM_IMPL(virDomainFeature, VIR_DOMAIN_FEATURE_LAST,
> "kvm",
> "pvspinlock",
> "capabilities",
> - "pmu")
> + "pmu",
> + "gic")
>
> VIR_ENUM_IMPL(virDomainCapabilitiesPolicy, VIR_DOMAIN_CAPABILITIES_POLICY_LAST,
> "default",
> @@ -14361,6 +14362,23 @@ virDomainDefParseXML(xmlDocPtr xml,
> ctxt->node = node;
> break;
>
> + case VIR_DOMAIN_FEATURE_GIC:
> + node = ctxt->node;
> + ctxt->node = nodes[i];
> + if ((tmp = virXPathString("string(./@version)", ctxt))) {
> + if (virStrToLong_ui(tmp, NULL, 10, &def->gic_version) < 0) {
> + virReportError(VIR_ERR_XML_ERROR,
> + _("malformed gic version: %s"), tmp);
> + goto error;
> + }
> + VIR_FREE(tmp);
I think you wan to use virStrToLong_uip... and would probably need to
check for an invalid value of zero (that way you can use that...)
> + } else {
> + def->gic_version = 2; /* By default, GIC version is 2 */
If not provided, then we're setting to the magic number of 2, which
means when we format it will be written out. Is that expected/desired?
I would think we should be able to handle things when the version is not
supplied. Furthermore, since it's possible (from the docs) that a
hypervisor doesn't support it, then setting a default could cause an issue.
> + }
> + def->features[val] = VIR_TRISTATE_SWITCH_ON;
> + ctxt->node = node;
> + break;
> +
> /* coverity[dead_error_begin] */
> case VIR_DOMAIN_FEATURE_LAST:
> break;
> @@ -16443,6 +16461,14 @@ virDomainDefFeaturesCheckABIStability(virDomainDefPtr src,
> return false;
> }
>
> + /* GIC version */
> + if (src->gic_version != dst->gic_version) {
> + virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> + _("Source GIC version '%u' does not match destination '%u'"),
> + src->gic_version, dst->gic_version);
> + return false;
> + }
> +
Obviously if the gic_version is enabled, so is gic; however, what if gic_
> /* hyperv */
> if (src->features[VIR_DOMAIN_FEATURE_HYPERV] == VIR_TRISTATE_SWITCH_ON) {
> for (i = 0; i < VIR_DOMAIN_HYPERV_LAST; i++) {
> @@ -20996,6 +21022,12 @@ virDomainDefFormatInternal(virDomainDefPtr def,
> virBufferAddLit(buf, "</capabilities>\n");
> break;
>
> + case VIR_DOMAIN_FEATURE_GIC:
> + if (def->features[i] == VIR_TRISTATE_SWITCH_ON)
> + virBufferAsprintf(buf, "<gic version='%u'/>\n",
> + def->gic_version);
> + break;
> +
Here's where I'd think that since gic_version is optional we'd have to
have a way to just print "<gic/>"; otherwise, it's not optional.
John
> /* coverity[dead_error_begin] */
> case VIR_DOMAIN_FEATURE_LAST:
> break;
> diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
> index 9955052..a79f0b8 100644
> --- a/src/conf/domain_conf.h
> +++ b/src/conf/domain_conf.h
> @@ -1649,6 +1649,7 @@ typedef enum {
> VIR_DOMAIN_FEATURE_PVSPINLOCK,
> VIR_DOMAIN_FEATURE_CAPABILITIES,
> VIR_DOMAIN_FEATURE_PMU,
> + VIR_DOMAIN_FEATURE_GIC,
>
> VIR_DOMAIN_FEATURE_LAST
> } virDomainFeature;
> @@ -2171,6 +2172,7 @@ struct _virDomainDef {
> int hyperv_features[VIR_DOMAIN_HYPERV_LAST];
> int kvm_features[VIR_DOMAIN_KVM_LAST];
> unsigned int hyperv_spinlocks;
> + unsigned int gic_version; /* by default 2 */
>
> /* These options are of type virTristateSwitch: ON = keep, OFF = drop */
> int caps_features[VIR_DOMAIN_CAPS_FEATURE_LAST];
>
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