On Fri, Jul 24, 2015 at 08:01:05AM -0400, Laine Stump wrote:
On 07/24/2015 07:28 AM, Martin Kletzander wrote:On Thu, Jul 23, 2015 at 03:18:04PM +0200, Ján Tomko wrote:On Fri, Jul 17, 2015 at 02:43:32PM -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 "type" attribute of the <model> subelement, e.g.:<controller type='pci' model='dmi-to-pci-bridge' index='1'> <model type='i82801b11-bridge'/> </controller>I'd say 'type' would be more fitting for the generic class of the device (dmi-to-pci-bridge), not the exact device model (i82801b11-bridge) so <model name='i82801b11-bridge'/> looks nicer to me, but I'm not going to suggest it again.Well, you just did. But I must say I like "model name" better too. When I pitched the "model type" I did that to show the creation of the new element, not the spelling itself.Using "model type" is based on the existing "model type" for <interface> and <video>. I also think "model name" is more fitting, but it breaks with precedent. Should we knowingly be inconsistent in order to make the new one better? I'm undecided.
We already have a model name='' too ;) Although it's not for devices, it's for a cpu... To be honest, I don't care, I'm rather thinking about how to make changes for inconsistencies work in the future without messing up the code, but with keeping the back-compat. I'm still naive enough that I believe there has to be a way.
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> type 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) --- new in V2 (previously was a part of the patch to add pcie-root-port) docs/formatdomain.html.in | 12 ++++++++++++ docs/schemas/domaincommon.rng | 13 +++++++++++++ src/conf/domain_conf.c | 23 +++++++++++++++++++++-- src/conf/domain_conf.h | 8 ++++++++ tests/qemuxml2argvdata/qemuxml2argv-q35.xml | 8 ++++++-- tests/qemuxml2xmloutdata/qemuxml2xmlout-q35.xml | 8 ++++++-- 6 files changed, 66 insertions(+), 6 deletions(-)diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index 50750c1..09fe3c0 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -797,6 +797,14 @@ typedef virDomainPCIControllerOpts *virDomainPCIControllerOptsPtr; struct _virDomainPCIControllerOpts { bool pcihole64; unsigned long pcihole64size; + + /* the type is in the "model" subelement, e.g.: + * <controller type='pci' model='pcie-root-port'> + * <model type='ioh3420''/> + * ... + * similar to the model of <interface> devices. + */ + char *type; /* the exact name of the device in hypervisor */This would be nicer as an enum - we don't allow arbitrary strings there anyway.The only place where we allow arbitrary strings is the interface model and due to that we're having some problems. Not allowing strings is good, storing the enum value is even better.Again, I used a string because that's the way it is in existing code (interface), but will change it to an enum for efficiency's sake. (I'm curious what problem you're refering to though - is it the fact that qemuBuildNicDevStr() doesn't qualify the string before using it in the commandline? That is taken care of in the case of this code.) -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
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