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

From: Sasha Levin
Date: Mon Aug 05 2019 - 14:37:00 EST


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?

--
Thanks,
Sasha