On Mon, Jun 08, 2020 at 05:18:44PM +0800, Jason Wang wrote:

On 2020/6/8 下午2:32, Michael S. Tsirkin wrote:

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On Mon, Jun 08, 2020 at 11:32:31AM +0800, Jason Wang wrote:

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On 2020/6/7 下午9:51, Michael S. Tsirkin wrote:

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On Fri, Jun 05, 2020 at 04:54:17PM +0800, Jason Wang wrote:

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On 2020/6/2 下午3:08, Jason Wang wrote:

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+static const struct pci_device_id vp_vdpa_id_table[] = {
+    { PCI_DEVICE(PCI_VENDOR_ID_REDHAT_QUMRANET, PCI_ANY_ID) },
+    { 0 }
+};

This looks like it'll create a mess with either virtio pci
or vdpa being loaded at random. Maybe just don't specify
any IDs for now. Down the road we could get a
distinct vendor ID or a range of device IDs for this.

Right, will do.

Thanks

Rethink about this. If we don't specify any ID, the binding won't work.

We can bind manually. It's not really for production anyway, so
not a big deal imho.

I think you mean doing it via "new_id", right.

I really meant driver_override. This is what people have been using
with pci-stub for years now.

Do you want me to implement "driver_overrid" in this series, or a NULL
id_table is sufficient?

Doesn't the pci subsystem create driver_override for all devices
on the pci bus?

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How about using a dedicated subsystem vendor id for this?

Thanks

If virtio vendor id is used then standard driver is expected
to bind, right? Maybe use a dedicated vendor id?

I meant something like:

static const struct pci_device_id vp_vdpa_id_table[] = {
     { PCI_DEVICE_SUB(PCI_VENDOR_ID_REDHAT_QUMRANET, PCI_ANY_ID,
VP_TEST_VENDOR_ID, VP_TEST_DEVICE_ID) },
     { 0 }
};

Thanks

Then regular virtio will still bind to it. It has

drivers/virtio/virtio_pci_common.c:     { PCI_DEVICE(PCI_VENDOR_ID_REDHAT_QUMRANET, PCI_ANY_ID) },

IFCVF use this to avoid the binding to regular virtio device.

Ow. Indeed:

#define IFCVF_VENDOR_ID         0x1AF4

Which is of course not an IFCVF vendor id, it's the Red Hat vendor ID.

I missed that.

Does it actually work if you bind a virtio driver to it?
I'm guessing no otherwise they wouldn't need IFC driver, right?

Looking at
pci_match_one_device() it checks both subvendor and subdevice there.

Thanks

But IIUC there is no guarantee that driver with a specific subvendor
matches in presence of a generic one.
So either IFC or virtio pci can win, whichever binds first.

I guess we need to blacklist IFC in virtio pci probe code. Ugh.

-- 
MST