Re: [libvirt] [PATCH 1/2] conf: add eim attribute to <iommu><driver>
On Thu, 2017-05-18 at 11:09 +0200, Ján Tomko wrote:
Add an attribute to control extended interrupt mode.
https://bugzilla.redhat.com/show_bug.cgi?id=1451282
[...]
@@ -7436,6 +7436,16 @@ qemu-kvm -net nic,model=? /dev/null
<span class="since">Since 3.4.0</span> (QEMU/KVM
only)
</p>
</dd>
+ <dt><code>eim</code></dt>
+ <dd>
+ <p>
+ The <code>eim</code> attribute with possible values
+ <code>on</code> and <code>off</code> can be used
to
+ turn on extended interrupt mode. In combination with intremap
+ and split I/O APIC, this allows for more vCPUs to be used.
+ <span class="since">Since 3.4.0</span> (QEMU/KVM
only)
+ </p>
+ </dd>
</dl>
</dd>
</dl>
Actually, the documentation could use some work too.
How about:
The <code>eim</code> attribute (with possible values
<code>on</code> and <code>off</code>) can be used to
configure Extended Interrupt Mode. A q35 domain with
split I/O APIC (as described in
<a href="#elementsFeatures">hypervisor features</a>),
and both interrupt remapping and EIM turned on for
the IOMMU, will be able to use more than 255 vCPUs.
<span class="since">Since 3.4.0</span> (QEMU/KVM only)
--
Andrea Bolognani / Red Hat / Virtualization