5:47 a.m.
This patch documents XML elements used for support of shmem
devices.
Considering there could be other shared memory related devices,
this patch introduces a general device model, called shmem device.
Currenly "ivshmem" is the only shared memory model supported.
About ivshmem, please see the following documentation:
http://git.qemu.org/?p=qemu.git;a=blob;f=docs/specs/ivshmem_device_spec.txt
(Ivshmem documentation for qemu will be updated soon:
http://lists.gnu.org/archive/html/qemu-devel/2014-08/msg01244.html)
In the devices section in the domain XML users may specify:
- For ivshmem device using an ivshmem server:
<shmem name='shmem0' model='ivshmem'>
<source file='/tmp/socket-ivshmem0'/>
<size unit='M'>32</size>
<msi vectors='32' ioeventfd='on'/>
</shmem>
- For ivshmem device not using an ivshmem server:
<shmem name='ivshmem1' model='ivshmem'>
<size unit='M'>32</size>
</shmem>
Signed-off-by: Maxime Leroy <maxime.leroy(a)6wind.com>
---
docs/formatdomain.html.in | 68 +++++++++++++++++++++++++++++++++++++++++++
docs/schemas/domaincommon.rng | 49 +++++++++++++++++++++++++++++++
2 files changed, 117 insertions(+)
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index ed17389..c7644bc 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -5422,6 +5422,74 @@ qemu-kvm -net nic,model=? /dev/null
</dd>
</dl>
+ <h4><a name="elementsShmem">Shmem device</a></h4>
+
+ <p>
+ A shmem (i.e. shared memory) device allows to share a memory
+ region between different virtual machines and the host.
+ </p>
+
+<pre>
+ ...
+ <devices>
+ <shmem name='shmem0' model='ivshmem'/>
+ <shmem name='shmem1' model='ivshmem'/>
+ </devices>
+ ...</pre>
+
+ <dl>
+ <dt><code>shmem</code></dt>
+ <dd>
+ The <code>shmem</code> element has one mandatory attribute,
+ <code>name</code> to identify the shared memory. The optional
element
+ <code>model</code> specify the type of shared memory. Only one mode
of
+ shared-memory is currently supported: <code>ivshmem</code>.
+ </dd>
+ </dl>
+
+ <h5><a name="elementsIvshmem">Ivshmem
model</a></h5>
+
+ <p>
+ An ivshmem (i.e. Inter-VM shared memory) device allows to share a memory
+ region (created on the host via the POSIX shared memory API) between
+ multiple QEMU processes running different guests.
+ For more information, please see the
+ <a
href="http://git.qemu.org/?p=qemu.git;a=blob;f=docs/specs/ivshmem_de...
+ ivshmem documentation of qemu</a>.
+ </p>
+
+<pre>
+ ...
+ <devices>
+ <shmem name='shmem0' model='ivshmem'>
+ <server path='/tmp/socket-shmem0'/>
+ <size unit='M'>32</size>
+ <msi vectors='32' ioeventfd='on'/>
+ </shmem>
+ <shmem name='shmem1' model='ivshmem'>
+ <size unit='M'>32</size>
+ </shmem>
+ </devices>
+ ...</pre>
+
+ <dl>
+ <dt><code>server</code></dt>
+ <dd>The optional <code>server</code> element can be used to
configure an
+ ivshmem device connected to the ivshmem server via a unix socket. The
+ <code>path</code> attribute specifies the path to the unix socket.
+ </dd>
+ <dt><code>size</code></dt>
+ <dd>The optional <code>size</code> element specifies the size of
the shared memory.
+ </dd>
+ <dt><code>msi</code></dt>
+ <dd>The optional <code>msi</code> element allows to enable MSI
interrupts.
+ This option can only be used with the <code>server</code> attribute.
+ The <code>vectors</code> attribute can be used to specify the number
of
+ interrupt vectors. The <code>ioeventd</code> attribute allows to
enable
+ ioeventfd.
+ </dd>
+ </dl>
+
<h3><a name="seclabel">Security label</a></h3>
<p>
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 033f2f6..64abf2b 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -3221,6 +3221,54 @@
</optional>
</element>
</define>
+
+ <define name="shmem">
+ <element name="shmem">
+ <attribute name="name"/>
+ <optional>
+ <ref name="ivshmem"/>
+ </optional>
+ <optional>
+ <ref name="alias"/>
+ </optional>
+ <optional>
+ <ref name="address"/>
+ </optional>
+ </element>
+ </define>
+
+ <define name="ivshmem">
+ <group>
+ <attribute name="model">
+ <value>ivshmem</value>
+ </attribute>
+ <interleave>
+ <optional>
+ <element name="server">
+ <attribute name="path"/>
+ </element>
+ </optional>
+ <optional>
+ <element name="msi">
+ <optional>
+ <ref name="ioeventfd"/>
+ </optional>
+ <optional>
+ <attribute name="vectors">
+ <ref name="unsignedInt"/>
+ </attribute>
+ </optional>
+ </element>
+ </optional>
+ <optional>
+ <element name="size">
+ <ref name="scaledInteger"/>
+ </element>
+ </optional>
+ </interleave>
+ </group>
+ </define>
+
<define name="memballoon">
<element name="memballoon">
<attribute name="model">
@@ -3807,6 +3855,7 @@
<ref name="redirfilter"/>
<ref name="rng"/>
<ref name="tpm"/>
+ <ref name="shmem"/>
</choice>
</zeroOrMore>
<optional>
--
1.9.3