Thanks for splitting these; I think that makes more sense. On Wed, Aug 14, 2019 at 12:38:54AM +0000, Haiyang Zhang wrote: > Currently in Azure cloud, for passthrough devices including GPU, the host > sets the device instance ID's bytes 8 - 15 to a value derived from the host > HWID, which is the same on all devices in a VM. So, the device instance > ID's bytes 8 and 9 provided by the host are no longer unique. This can > cause device passthrough to VMs to fail because the bytes 8 and 9 are used > as PCI domain number. Collision of domain numbers will cause the second > device with the same domain number fail to load. I think this patch is fine. I could be misunderstanding the commit log, but when you say "the ID bytes 8 and 9 are *no longer* unique", that suggests that they *used* to be unique but stopped being unique at some point, which of course raises the question of *when* they became non-unique. The specific information about that point would be useful to have in the commit log, e.g., is this related to a specific version of Azure, a configuration change, etc? Does this problem affect GPUs more than other passthrough devices? If all passthrough devices are affected, why mention GPUs in particular? I can't tell whether that information is relevant or superfluous. Bjorn
