Currently, the CPU feature 'name' XML attribute, as in: [...] <cpu match='exact'> <model fallback='forbid'>IvyBridge</model> <vendor>Intel</vendor> <feature policy='require' name='pcid'/> </cpu> [...] isn't explicitly documented in formatdomain.html. Document it now. Signed-off-by: Kashyap Chamarthy <kchamart(a)redhat.com&gt; --- docs/formatdomain.html.in | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index d272cc1ba..e717fb3aa 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -1454,6 +1454,23 @@ <span class="since">Since 0.8.5</span> the <code>policy</code> attribute can be omitted and will default to <code>require</code>. + + Individual CPU feature names can be specified as part of the + <code>name</code> attribute.

The list of known CPU feature + names (e.g. 'vmx', 'cmt', et cetera) can be found in the same + file as CPU models -- <code>cpu_map.xml</code>. For example, + to explicitly specify the 'pcid' feature with Intel IvyBridge + CPU model:

+ +<pre> +... +&lt;cpu match='exact'&gt; + &lt;model fallback='forbid'&gt;IvyBridge&lt;/model&gt; + &lt;vendor&gt;Intel&lt;/vendor&gt; + &lt;feature policy='require' name='pcid'/&gt; +&lt;/cpu&gt; +...</pre> + </dd> <dt><code>cache</code></dt> -- 2.13.6

On Tue, Jan 16, 2018 at 03:35:20PM -0200, Eduardo Habkost wrote: > On Fri, Jan 12, 2018 at 08:31:16PM +0100, Kashyap Chamarthy wrote: > > Currently, the CPU feature 'name' XML attribute, as in: [...] > > --- > > docs/formatdomain.html.in | 17 +++++++++++++++++ > > 1 file changed, 17 insertions(+) > > > > diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in > > index d272cc1ba..e717fb3aa 100644 > > --- a/docs/formatdomain.html.in > > +++ b/docs/formatdomain.html.in > > @@ -1454,6 +1454,23 @@ > > > > <span class="since">Since 0.8.5</span> the <code>policy</code> > > attribute can be omitted and will default to <code>require</code>. > > + > > + Individual CPU feature names can be specified as part of the > > + <code>name</code> attribute. > > Isn't this "should" instead of "can"? Does it make sense to have > a 'feature' element without a 'name' attribute? Good catch. Near as I see, it doesn't. So I'll: s/can/should. > > > The list of known CPU feature > > + names (e.g. 'vmx', 'cmt', et cetera) can be found in the same > > + file as CPU models -- <code>cpu_map.xml</code>. For example, > > + to explicitly specify the 'pcid' feature with Intel IvyBridge > > + CPU model: > > Another paragraph above already says "The list of known feature > names can be found in the same file as CPU models". If you think the > existing paragraph is not enough, I suggest rewriting it so the > document won't repeat exactly the same thing. True. How about this rewrite: "Once you choose a feature (e.g. 'pcid') from the `cpu_map.xml`, to specify it explicitly with the Intel IvyBridge CPU model [...]"

I'll consider whether to also add a note that before specifying extra CPU feature flags, one should check if the named CPU models provided by libvirt already include the said flags.