On Sat, Jul 25, 2015 at 03:58:25PM -0400, Laine Stump wrote:
This new subelement is used in PCI controllers: the toplevel
*attribute* "model" of a controller denotes what kind of PCI
controller is being described, e.g. a "dmi-to-pci-bridge",
"pci-bridge", or "pci-root". But in the future there will be different
implementations of some of those types of PCI controllers, which
behave similarly from libvirt's point of view (and so should have the
same model), but use a different device in qemu (and present
themselves as a different piece of hardware in the guest). In an ideal
world we (i.e. "I") would have thought of that back when the pci
controllers were added, and used some sort of type/class/model
notation (where class was used in the way we are now using model, and
model was used for the actual manufacturer's model number of a
particular family of PCI controller), but that opportunity is long
past, so as an alternative, this patch allows selecting a particular
implementation of a pci controller with the "name" attribute of the
<model> subelement, e.g.:
<controller type='pci' model='dmi-to-pci-bridge' index='1'>
<model name='i82801b11-bridge'/>
</controller>
In this case, "dmi-to-pci-bridge" is the kind of controller (one that
has a single PCIe port upstream, and 32 standard PCI ports downstream,
which are not hotpluggable), and the qemu device to be used to
implement this kind of controller is named "i82801b11-bridge".
Implementing the above now will allow us in the future to add a new
kind of dmi-to-pci-bridge that doesn't use qemu's i82801b11-bridge
device, but instead uses something else (which doesn't yet exist, but
qemu people have been discussing it), all without breaking existing
configs.
(note that for the existing "pci-bridge" type of PCI controller, both
the model attribute and <model> name are 'pci-bridge'. This is just a
coincidence, since it turns out that in this case the device name in
qemu really is a generic 'pci-bridge' rather than being the name of
some real-world chip)
---
change from V2:
* attribute is now called "name" instead of "type"
* different possible model names are stored internally as an enum
value rather than a string.
* more than one occurence of <model> in a single controller is now
considered an error
* docs say "1.2.18" instead of "1.3.0"
docs/formatdomain.html.in | 13 +++++++
docs/schemas/domaincommon.rng | 13 +++++++
src/conf/domain_conf.c | 46 +++++++++++++++++++++++--
src/conf/domain_conf.h | 16 +++++++++
src/libvirt_private.syms | 2 ++
tests/qemuxml2argvdata/qemuxml2argv-q35.xml | 8 +++--
tests/qemuxml2xmloutdata/qemuxml2xmlout-q35.xml | 8 +++--
7 files changed, 100 insertions(+), 6 deletions(-)
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index d0c1741..9abceee 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -3042,6 +3042,19 @@
(set to 0). <span class="since">Since 1.1.2 (QEMU only)</span>
</p>
<p>
+ PCI controllers also have an optional
+ subelement <code><model></code> with an attribute
+ <code>name</code>. The name attribute holds the name of the
+ specific device that qemu is emulating (e.g. "i82801b11-bridge")
+ rather than simply the class of device ("dmi-to-pci-bridge",
+ "pci-bridge"), which is set in the controller element's
+ model <b>attribute</b>. In almost all cases, you should not
+ manually add a <code><model></code> subelement to a
+ controller, nor should you modify one that is automatically
+ generated by libvirt. <span class="since">Since 1.2.18 (QEMU
Oh, I forgot to ask you to change this to 1.2.19 ^^, sorry about missing not just the rc1, but the whole release. But I was partly offline for the whole week as well and I hoped someone else might pick this up... Martin
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