I've pushed kernel side vfio vga support to my next branch and intend
to try to get those in for kernel v3.9. Those changes can be found
here: git://github.com/awilliam/linux-vfio.git (next)
This is the matching QEMU updates. Patch 1/2 adds basic VGA range
support. This can be used with the option "-vga none" to disable
emulated VGA and also requires vfio-pci device option "x-vga=on". As
noted by the x- prefix, this support is entirely experimental.
Expectations should range anywhere from working perfectly to crashing
the host.
Patch 2/2 contains numerous quirks for devices that I have onhand to
test, but hopefully covers a faily broad spectrum (at least for
ATI/AMD and Nvidia). These quirks trap various device specific
addresses and insert device virtual addresses in place of device
physical addresses. If we could identity map devices we could avoid
these, but that also puts numerous constraints on our configuration.
The vfio kernel VGA support makes use of the VGA arbiter to switch
between host VGA devices and I have been successful in running
multiple devices simultaneously. At this point only secondary
devices have been tested. The primary graphics likely needs extra
work to completely turn off host kernel access. Intel integrated
graphics have not been tested and are most certainly broken as
they require access to devices other than the VGA device alone.
Nvidia devices will work with nouveau in Linux guests, but do not
work with Nvidia drivers in Windows (probably Linux too). I think
we need to put these behind emulated PCIe root ports before they'll
work, but Q35 doesn't work well enough for that yet. ATI/AMD cards
seem to have the best hope of working with their Catalyst drivers.
For best results, use Q35, -vga none, x-vga=on, and x-bustype=2,
for example:
-M q35 -vga none -device vfio-pci,host=x:xx.x,x-vga=on,x-bustype=2
All the qemu patches necessary for this can be found in this branch:
git://github.com/awilliam/qemu-vfio.git (vfio-vga-v3)
This series will depend on a kernel header update which I'll send
patches for once the kernel patches are upstream. Thanks,
Alex
---
Alex Williamson (2):
qemu vfio-pci: Add support for VGA MMIO and I/O port access
qemu vfio-pci: Graphics device quirks
hw/vfio_pci.c | 651 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 649 insertions(+), 2 deletions(-)
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