On Thu, Jan 13, 2022 at 04:08:07PM -0800, Iouri Tarassov wrote: > > On 1/12/2022 11:46 PM, Greg KH wrote: > > On Wed, Jan 12, 2022 at 11:55:06AM -0800, Iouri Tarassov wrote: > > > + dev_dbg(dxgglobaldev, "%s: %x:%x %p %pUb\n", > > > + __func__, adapter->luid.b, adapter->luid.a, hdev->channel, > > > + &hdev->channel->offermsg.offer.if_instance); > > > > When I see something like "global device pointer", that is a HUGE red > > flag. > > > > No driver should ever have anything that is static to the driver like > > this, it should always be per-device. Please use the correct device > > model here, which does not include a global pointer, but rather unique > > ones that are given to you by the driver core. That way you are never > > tied to only "one device per system" as that is a constraint that you > > will have to fix eventually, might as well do it all correctly the first > > time as it is not any extra effort to do so > Hi Greg, > > dxgglobaldev is a pointer to the global driver data. By design there is a > single hyper-v VM bus and a single corresponding /dev/dxg device. That's fine, but use the pointer that you create based on your bus device, not some static pointer please. > Virtual GPU adapters are present on the VM bus. /dev/dxg device is used > to enumerate all virtual GPUs, which are accessible only via IOCTLs > to /dev/dxg. dxgglobaldev has a list of all vGPU adapters and > other global driver state. This follows the design on Windows where a single > global object in dxgkrnl.sys driver is used to enumerate and access all > GPU devices. This is also how the public D3DKMT interface to dxgkrnl is > structured. First off, remember this isn't Windows, let's not make the same mistakes they have made there please :) Secondly, this isn't the problem, the issue is that you have a non-dynamic device here, which is not how Linux drivers should ever work. It's fine to have a "mux" device like this, but create it properly, based on the device that the driver core gives you as you must respect that lifetime, not the lifetime of a static pointer embedded in a module. thanks, greg k-h
