Re: [PATCH] PCI: hv: Detect and fix Hyper-V PCI domain number collision

From: Bjorn Helgaas
Date: Tue Aug 06 2019 - 14:55:37 EST


On Mon, Aug 05, 2019 at 02:36:57PM -0400, Sasha Levin wrote:
> On Fri, Aug 02, 2019 at 06:52:56PM +0000, Haiyang Zhang wrote:
> > Due to Azure host agent settings, the device instance ID's bytes 8 and 9
> > are no longer unique. This causes some of the PCI devices not showing up
> > in VMs with multiple passthrough devices, such as GPUs. So, as recommended
> > by Azure host team, we now use the bytes 4 and 5 which usually provide
> > unique numbers.
> >
> > In the rare cases of collision, we will detect and find another number
> > that is not in use.
> > Thanks to Michael Kelley <mikelley@xxxxxxxxxxxxx> for proposing this idea.

> > Signed-off-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
>
> Acked-by: Sasha Levin <sashal@xxxxxxxxxx>
>
> Bjorn, will you take it through the PCI tree or do you want me to take
> it through hyper-v?

Lorenzo usually applies patches to drivers/pci/controller/*, so that
would be my preference.

Bjorn