[libvirt] [PATCH v2 14/16] qemu: build vhost-user GPU devices

[Marc-André Lureau]

Hi

On Tue, Aug 27, 2019 at 1:17 PM Ján Tomko <jtomko at redhat.com> wrote:
>
> On Fri, Aug 23, 2019 at 12:21:58PM -0400, Cole Robinson wrote:
> >From: Marc-André Lureau <marcandre.lureau at redhat.com>
> >
> >For each vhost-user GPUs,
> >- build a socket chardev, and pass the vhost-user socket to it
> >- build a vhost-user video device and associate it with the chardev
> >
> >Signed-off-by: Marc-André Lureau <marcandre.lureau at redhat.com>
> >Signed-off-by: Cole Robinson <crobinso at redhat.com>
> >---
> > src/qemu/qemu_command.c | 46 +++++++++++++++++++++++++++++++++++++++--
> > 1 file changed, 44 insertions(+), 2 deletions(-)
> >
> >diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> >index 8bef103f68..0e1d9510e5 100644
> >--- a/src/qemu/qemu_command.c
> >+++ b/src/qemu/qemu_command.c
> >@@ -4672,8 +4672,15 @@ qemuBuildDeviceVideoStr(const virDomainDef *def,
> >         goto error;
> >     }
> >
> >-    if (STREQ(model, "virtio-gpu")) {
> >-        if (qemuBuildVirtioDevStr(&buf, "virtio-gpu", qemuCaps,
>
> Eww, why do we do a string comparison here when we store the model as an
> enum?

Yup, pre-existing. I suppose that can be fixed.

>
> >+    if (video->vhostuser) {
> >+        if (STREQ(model, "virtio-vga"))
> >+            model = "vhost-user-vga";
> >+        if (STREQ(model, "virtio-gpu"))
> >+            model = "vhost-user-gpu";
> >+    }
>
> Not sure why we need to reassign model here instead of getting it right
> the first time.
>
> >+
>
> How different is the vhost-user-gpu device from virtio-gpu,
> don't we new a new VIDEO_TYPE_VHOST_USER instead?

>From guest PoV, it's actually the same device. So we shouldn't
introduce a new virDomainVideoType, right? But we need a mapping to
-device, it has to be in libvirt qemu driver.


>
>
> if (video->type == VIRTIO && !primary) for the condition below:
>
> >+    if (STREQ(model, "virtio-gpu") || STREQ(model, "vhost-user-gpu")) {
> >+        if (qemuBuildVirtioDevStr(&buf, model, qemuCaps,
> >                                   VIR_DOMAIN_DEVICE_VIDEO, video) < 0) {
> >             goto error;
> >         }
>
> Jano
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-- 
Marc-André Lureau