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. 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. Thanks Iouri
