Re: [libvirt] [PATCH v2 5/7] conf: Introduce new <hostdev> attribute 'display'
On Wed, Jul 11, 2018 at 10:09:01AM +0200, Michal Privoznik wrote:
On 07/11/2018 09:58 AM, Erik Skultety wrote:
> On Tue, Jul 10, 2018 at 01:39:03PM +0200, Michal Privoznik wrote:
>> On 07/09/2018 06:24 PM, Erik Skultety wrote:
>>> QEMU 2.12 introduced a new type of display for mediated devices using
>>> vfio-pci backend which allows a mediated device to be used as a VGA
>>> compatible device as an alternative to an emulated video device. QEMU
>>> exposes this feature via a vfio device property 'display' with
supported
>>> values 'on/off/auto' (default is 'off').
>>>
>>> This patch adds the necessary bits to domain config handling in order to
>>> expose this feature. Since there's no convenient way for libvirt to
come
>>> up with usable defaults for the display setting, simply because libvirt
>>> is not able to figure out which of the display implementations - dma-buf
>>> which requires OpenGL support vs vfio regions which doesn't need OpenGL
>>> (works with OpenGL enabled too) - the underlying mdev uses.
>>>
>>> Signed-off-by: Erik Skultety <eskultet(a)redhat.com>
>>> ---
> ...
>
>>> +static int
>>> +qemuDomainHostdevDefPostParse(const virDomainHostdevDef *hostdev,
>>> + const virDomainDef *def)
>>> +{
>>> + const virDomainHostdevSubsysMediatedDev *mdevsrc;
>>> +
>>> + if (hostdev->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS) {
>>> + switch ((virDomainHostdevSubsysType)
hostdev->source.subsys.type) {
>>> + case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB:
>>> + case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI:
>>> + case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_SCSI:
>>> + case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_SCSI_HOST:
>>> + break;
>>> + case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_MDEV:
>>> + mdevsrc = &hostdev->source.subsys.u.mdev;
>>> + return qemuDomainHostdevMdevDefPostParse(mdevsrc, def);
>>> + case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_LAST:
>>> + default:
>>> + virReportEnumRangeError(virDomainHostdevSubsysType,
>>> + hostdev->source.subsys.type);
>>> + return -1;
>>> + }
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>
>> Again, these two ^^ are validate callbacks not PostParse. You are not
>> filling in missing information, you are checking (=validating) whether
>> user provided XML is valid.
>
> Actually, both of them were, back in the RFC series I linked (I completely
> agree with you) but I was asked to convert them to post parse so that xml2xml
> test could fail for invalid XMLs. Let me know whether I should convert them
> back.
Asked by whom?
Here you go
https://www.redhat.com/archives/libvir-list/2018-June/msg00285.html.
Revisiting it back I believe it was a combination of a small misunderstanding
and my lazy thinking, so yep, I reverted the change back to being a validation
callback and moved the *-missing-graphics* test into patch 7 where it's
actually used.
Erik