On Tue, 2016-02-02 at 07:54 -0700, Alex Williamson wrote: > > I first glance I like it, but there's a problem, it assumes there is a > host driver for the device that will permanently release the device from > the RMRR even after the device is unbound. Currently we don't have a > requirement that the user must first bind the device to a native host > driver, unbind it, and only then is it eligible for device assignment.
It doesn't *have* to be a full native driver. It can be a PCI quirk (the USB controllers could potentially do it that way, although they don't). Or a stub 'shut it down' driver, potentially even done somehow through VFIO. But fundamentally, in all of these cases you have to do *something* to stop the BIOS-controlled DMA. Otherwise the RMRR shouldn't have been there in the first place, surely? But for the gfx case... what *do* we have to do? Does the VMM (and the VM's BIOS, between them) have to provision a "stolen" region of guest memory and point the gfx framebuffer at that? Once we have a proper handle on precisely what needs to happen, we can have a better conversation about where/how to do that... -- David Woodhouse Open Source Technology Centre david.woodho...@intel.com Intel Corporation
smime.p7s
Description: S/MIME cryptographic signature
