On Mon, 27 Apr 2020 10:22:18 -0300 Jason Gunthorpe <jgg@xxxxxxxxxxxx> wrote: > On Mon, Apr 27, 2020 at 07:19:39AM -0600, Alex Williamson wrote: > > > > It is not trivial masking. It is a 2000 line patch doing comprehensive > > > emulation. > > > > Not sure what you're referring to, I see about 30 lines of code in > > vdcm_vidxd_cfg_write() that specifically handle writes to the 4 BARs in > > config space and maybe a couple hundred lines of code in total handling > > config space emulation. Thanks, > > Look around vidxd_do_command() > > If I understand this flow properly.. I've only glanced at it, but that's called in response to a write to MMIO space on the device, so it's implementing a device specific register. Are you asking that PCI config space be done in userspace or any sort of device emulation? The assumption with mdev is that we need emulation in the host kernel because we need a trusted entity to mediate device access and interact with privileged portion of the device control. Thanks, Alex
