qemu/docs/igd-assign.txt

1 Intel Graphics Device (IGD) assignment with vfio-pci
4 Using vfio-pci, we can passthrough Intel Graphics Device (IGD) to guest, either
16 (*-Required by)
19 |---------------------------------------------|-------|---------|-------|---------|
30 For #1, the "x-igd-opregion=on" option exposes a copy of host IGD OpRegion to
33 For #2, "x-igd-lpc=on" option copies the IDs of host LPC bridge and host bridge
42 For #5, "x-vga=on" enables guest access to standard VGA IO/MMIO ranges.
48 QEMU also provides a "Legacy" mode that implicitly enables full functionality
55 In "Legacy" mode, QEMU will automatically setup OpRegion, LPC bridge IDs and
57   x-igd-opregion=on,x-igd-lpc=on,x-vga=on
59 By default, "Legacy" mode won't fail, it continues on error. User can set
60 "x-igd-legacy-mode=on" to force enabling legacy mode, this also checks if the
61 conditions above for legacy mode is met, and if any error occurs, QEMU will
62 fail immediately. Users can also set "x-igd-legacy-mode=off" to disable legacy
65 In legacy mode, as the guest VGA ranges are assigned to IGD device, all other
66 graphics devices should be removed, this can be done using "-nographic" or
67 "-vga none" or "-nodefaults", along with adding the device using vfio-pci.
70 may generate faults and errors upon re-binding to an IGD device after it
74 the driver_override option can be used to ensure that only vfio-pci can bind
75 to the device on the host[2], virsh nodedev-detach can be used to bind the
77 re-binding to i915, etc.  Also note that IGD is also typically the primary
79 blacklisting i915 or using pci-stub/vfio-pci to take ownership of IGD as a
83 a catch-all, video=vesafb:off,efifb:off.  Error messages such as:
105 * x-igd-opregion=[*on*|off]
108 * x-igd-lpc=[on|*off*]
111 * x-igd-legacy-mode=[on|off|*auto*]
112   Enable/Disable legacy mode
114 * x-igd-gms=[hex, default 0]
117   'DVMT Pre-Allocated' option in host BIOS.
122 * Adding IGD with automatically legacy mode support
123   -device vfio-pci,host=00:02.0,id=hostdev0,addr=2.0
127 …-device vfio-pci,host=00:02.0,id=hostdev0,addr=2.0,x-igd-legacy-mode=off,x-igd-lpc=on,romfile=efi_…
136 1) "etc/igd-opregion"
147 2) "etc/igd-bdsm-size"
149    This fw_cfg file contains an 8-byte, little endian integer indicating
155    64-bit BDSM).  As this support is related to running the IGD ROM, which
166 Upstream Seabios has OpRegion and BDSM (pre-Gen11 device only) support.
171 * IntelGopDriver: Closed-source Intel GOP driver
179 You need to build them with EDK2.
188   EfiRom -f 0x8086 -i <Device ID of your IGD> -o output.rom \
189   -e IgdAssignmentDxe.efi PlatformGOPPolicy.efi IntelGopDriver.efi
195 warning: vfio_container_dma_map(0x55fab36ce610, 0x380010000000, 0x108000, 0x7fd336000000) = -22 (In…
199   -cpu host,host-phys-bits-limit=<IOMMU address width>
205   echo $(( ((0x$(cat /sys/devices/virtual/iommu/dmar0/intel-iommu/cap) & 0x3F0000) >> 16) + 1 ))
211 IGD has it own address space. To use system RAM as VRAM, a single-level page
214 the translation flow on IGD with 64-bit GTT PTEs.
216 (PTE_SIZE == 8)                +-------------+---+
218                                +-------------+---+
221 -----------------------> 0xd748| 0x42ba3e000 | 1 +------------------>
224                                +-------------+---+
232 The Data Stolen Memory is reserved by firmware, and acts as the VRAM in pre-OS
239        +-------------+                +-------------+         +-------------+
242        |             |                +-------------+         +-------------+
245        |             |  +------------>+-------------+<------->+-------------+<--Guest BDSM
247 DSMSIZE+-------------+  | with IOMMU  |             | Mapping |             |   Programmed by guest…
250       0+-------------+--+             |             |         |             |
251                         |             +-------------+         |             |
252                         |             | Data Stolen |         +-------------+
254                         +------------>+-------------+<--Host BDSM
255                           Non-        |             |   "real" one in HW
257                                       +-------------+
261 …https://www.intel.com/content/www/us/en/docs/graphics-for-linux/developer-reference/1-0/dump-video…
262 [2] # echo "vfio-pci" > /sys/bus/pci/devices/0000:00:02.0/driver_override
265 [4] https://eci.intel.com/docs/3.3/components/kvm-hypervisor.html, Patch 0001-0004
267 [6] https://winraid.level1techs.com/t/tool-guide-news-uefi-bios-updater-ubu/30357