On 06/24/14 01:30, Eric Blake wrote:
> Add an element to QEMU's capability XML, to show if the underlying
> qemu binary supports active commit. This allows the client to know
> ahead of time if they can rely on this method, or must fall back
> to older techniques such as blockpull. Without this information,
> the only way to check for active commit is to attempt one and check
> for errors.
>
> This attribute can be a simple binary (active commit is supported
> only if <activecommit/> is in the capabilities) rather than a
> full-blown toggle definition. (In contrast, the <disksnapshot>
> capability had to be a toggle because we forgot to add it at the
> same time as turning on the feature of external snapshots; and
> therefore, the absence of the attribute is not sufficient to
> conclude whether disk snapshots are supported.)
>
> Our documentation for features was rather sparse; this fleshes out
> more of the details for other existing capabilities (and cost me
> some time trawling git history).
>
> * docs/schemas/capability.rng (features): Add activecommit.
> * docs/formatcaps.html.in: Document it, and other features.
> * src/qemu/qemu_capabilities.c (virQEMUCapsInitGuestFromBinary):
> Set it.
> * src/conf/capabilities.c (virCapabilitiesFormatXML): Expose as
> simpler binary.
>
> Signed-off-by: Eric Blake <eblake@xxxxxxxxxx>
> ---
> docs/formatcaps.html.in | 46 +++++++++++++++++++++++++++++++++++++++++++-
> docs/schemas/capability.rng | 5 +++++
> src/conf/capabilities.c | 3 ++-
> src/qemu/qemu_capabilities.c | 6 ++++++
> 4 files changed, 58 insertions(+), 2 deletions(-)
>
> diff --git a/docs/formatcaps.html.in b/docs/formatcaps.html.in
> index 137af25..6ac0f4a 100644
> --- a/docs/formatcaps.html.in
> +++ b/docs/formatcaps.html.in
> @@ -95,7 +95,51 @@
>
> <dt><code>features</code></dt>
> <dd>This optional element encases possible features that can be used
> - with a guest of described type.</dd>
> + with a guest of described type. Possible subelements are:
> + <dl>
> + <dt>pae</dt><dd>If present, 32-bit guests can use PAE
> + address space extensions, <span class="since">since
> + 0.4.1</span></dd>
> + <dt>nonpae</dt><dd>If present, 32-bit guests can be run
> + without requiring PAE, <span class="since">since
> + 0.4.1</span></dd>
> + <dt>ia64_be</dt><dd>If present, IA64 guests can be run in
> + big-endian mode, <span class="since">since 0.4.1</span></dd>
> + <dt>acpi</dt><dd>If this element is present,
> + the <code>default</code> attribute describes whether the
> + hypervisor exposes ACPI to the guest by default, and
> + the <code>toggle</code> attribute describes whether the
> + user can override this
> + default. <span class="since">Since 0.4.1</span></dd>
> + <dt>apic</dt><dd>If this element is present,
> + the <code>default</code> attribute describes whether the
> + hypervisor exposes APIC to the guest by default, and
> + the <code>toggle</code> attribute describes whether the
> + user can override this
> + default. <span class="since">Since 0.4.1</span></dd>
> + <dt>cpuselection</dt><dd>If this element is present, the
> + hypervisor supports the <code><cpu></code> element
> + within a domain definition for fine-grained control over
> + the CPU presented to the
> + guest. <span class="since">Since 0.7.5</span></dd>
> + <dt>deviceboot</dt><dd>If this element is present,
> + the <code><boot order='...'/></code> element can
> + be used inside devices, rather than the older boot
> + specification by category. <span class="since">Since
> + 0.8.8</span></dd>
> + <dt>disksnapshot</dt><dd>If this element is present,
> + the <code>default</code> attribute describes whether
> + external disk snapshots are supported. If absent,
> + external snapshots may still be supported, but it
> + requires attempting the API and checking for an error to
> + find out for sure. <span class="since">Since
> + 1.2.3</span></dd>
> + <dt>activecommit</dt><dd>Active commit (via the
> + virDomainBlockCommit API) is supported only if this
> + element is present. <span class="since">Since
> + 1.2.6</span></dd>
> + </dl>
> + </dd>
> </dl>
>
> <h3><a name="elementExamples">Examples</a></h3>
> diff --git a/src/conf/capabilities.c b/src/conf/capabilities.c
> index 19359a5..ebf6121 100644
> --- a/src/conf/capabilities.c
> +++ b/src/conf/capabilities.c
> @@ -1005,7 +1005,8 @@ virCapabilitiesFormatXML(virCapsPtr caps)
> STREQ(caps->guests[i]->features[j]->name, "nonpae") ||
> STREQ(caps->guests[i]->features[j]->name, "ia64_be") ||
> STREQ(caps->guests[i]->features[j]->name, "cpuselection") ||
> - STREQ(caps->guests[i]->features[j]->name, "deviceboot")) {
> + STREQ(caps->guests[i]->features[j]->name, "deviceboot") ||
> + STREQ(caps->guests[i]->features[j]->name, "activecommit")) {
> virBufferAsprintf(&buf, "<%s/>\n",
> caps->guests[i]->features[j]->name);
> } else {
> diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
> index d698db9..d1d33d5 100644
> --- a/src/qemu/qemu_capabilities.c
> +++ b/src/qemu/qemu_capabilities.c
> @@ -822,6 +822,12 @@ virQEMUCapsInitGuestFromBinary(virCapsPtr caps,
> if (!virCapabilitiesAddGuestFeature(guest, "disksnapshot", hasdisksnapshot, 0))
> goto cleanup;
>
> + if (!virCapabilitiesAddGuestFeature(guest, "activecommit",
> + virQEMUCapsGet(qemubinCaps,
> + QEMU_CAPS_ACTIVE_COMMIT),
> + 0))
Yuck, integers for boolean values. Pre-existing though.
> + goto cleanup;
> +
> if (virCapabilitiesAddGuestDomain(guest,
> "qemu",
> NULL,
>
ACK,
Peter
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