- ROOT_DISK_IMG is now dynamic (ROOT_DISK_IMG=/path/to/existing/provisioned/disk.img can be reused across run statements)
- Addition of missing boards to cover all use cases
- All TPM1 boards rely on common config/coreboot-qemu-tpm1.config
- boards/qemu-coreboot-fbwhiptail-tpm1-hotp/qemu-coreboot-fbwhiptail-tpm1-hotp.md has been generalized
- all other boards are softlinked to the above for usage
This makes configs much less dependent on directory layout.
As of this commit the following variables are supported:
* @BOARD_BUILD_DIR@ - absolute path under build/
* @BLOB_DIR@ - absolute path to blobs/
Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
Enable virtio video and storage.
Enable serial console and tweak kernel command line to show logs.
Signed-off-by: Jonathon Hall <jonathon.hall@puri.sm>
Add qemu-coreboot-fbwhiptail-tpm1-hotp configuration, which has a 'run'
target to boot with a persistent TPM, disk, virtual USB disk, and USB-
forwarded token
Provide instructions for bootstrapping a complete working system in qemu
Signed-off-by: Jonathon Hall <jonathon.hall@puri.sm>
Set ATA and SATA configs to y, not m - modules weren't being loaded. Other
configs also build these into kernel, so do the same for qemu. Remove relevant
configs from boards since modules no longer need to be in initrd.
Enable OHCI and UHCI. qemu forwards host USB devices over a UHCI controller.
This enables USB-forwarding a physical Librem Key or Nitrokey Pro to the VM.
Export CONFIG_LINUX_USB_COMPANION_CONTROLLER to have enable_usb() load the
modules - it wants both UHCI and OHCI modules, so build both.
Signed-off-by: Jonathon Hall <jonathon.hall@puri.sm>
EC signatures requires that the digest has the corresponding length. Removing the hardcoded sha2-256 hash function and adding support of sha2-384 and sha2-512 should allow using EC crypto.
- this boards is a duplicate of x230-hotp-maximized with USB Keyboard support
Testing points:
- x230-hotp-maximized does not accept input from USB keyboard
- x230-hotp-maximized_usb-kb accepts input from USB keyboard
Testing point:
- All board configs not explicitely stating export CONFIG_USB_KEYBOARD=y should not have any impact
- librem_l1um, kgpe-d16_workstation-usb_keyboard, librem_mini_v2 and librem_mini will loose USB Keyboard input with this commit alone.
Those boards now produce 4MB coreboot ROM and according CBFS small size, and remove the logic to extract 4Mb ROM out of the 12Mb rom which for some reason, was now misaligned.
config/coreboot-xx30-flash : remove all unnneded stuff to xx30-flash boards.
config/linux-x230-flash: used commonly for all xx30-flash boards, this is now finally saved with savedeconfig, and removes another bunch of unneeded stuff.
Tested working. Fixes#1095
This commit adds explanatory notes and updates existing t530 and w530 boards to generally align them with the dGPU points and provide signposting for those with and those without dGPU boards. It also adds an additional README in the blobs directory to explain the vbios extraction and building process.
This commit adds support for the t530 and w530 boards to enable dGPUs. dGPU's are required for DisplayPort external displays in the t530 dgpu model, and for both the VGA dn DisplayPort external displays in the W530 (which has two dGPUs, the K1000M and K2000M, hence two boards). The commit does the following:
1. Adds automated extraction scripts for vbios modelled on the me script in the blobs directory (one per board is necessary as it is based on board-specific bios updates).
2. Adds specific boards for the various dGPU models and corresponding coreboot configs.
3. Updates circleci config.yaml to run scripts and test boards.
Tested and working on T530 dgpu and W530 K1000M. dGPU scripts tested on Debian 10 and Ubuntu 21.04
Resolves issues booting Qubes 4.1-RC1 installer. Drop log level
to be consistent with the Librem 14/Mini v1/v2.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
Update all Purism Librem boards except the L1UM server
to coreboot 4.15:
- update coreboot version from 4.8.1/4.13 to 4.15
- use purism_blobs module (if not already)
- update board coreboot defconfig files (Librem 13/15)
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
-CircleCI addition.
-Removal of t530-flash, w530-flash boards, flash scripts and associated coreboot configs (no more legacy boards additions)
This is a merger of #1071, #1072 and #1073 so that test builds are available over CircleCI until osresearch/master CircleCI gets unlocked.
- xx30 legacy boards (x230, x230-flash, t430, t430-flash) now rely also on coreboot 4.13
- DOWNSIDE: x230 and t430 legacy boards now rely on WHIPTAIL (NOT FBWhiptail) to have enough space to fit under 7mb)
- xx20 boards moved to 4.13 (no need of xx20-flash boards here since single SPI boards with 7.5mb useable since blobs scripts are required)
- DOWNSIDE: all xx20 boards now have dropbear deactivated, while still having ethernet driver in.
- qemu-coreboot and qemu-coreboot-fbwhiptail switched to coreboot 4.13 WITHOUT TPM SUPPORT (with cryptsetup 2.x support)
- DOWNSIDE:
- coreboot-qemu board CBFS_SIZE=0x700000 -> 0x750000
- coreboot-qemu-fbwhiptail CBFS_SIZE=0x750000 -> 0x780000
- CircleCi build recipe removes 4.8.1 boards altogether
- KGPE-D16 workstation is used as new base build to save workspace layer (we removed one workspace layer)
- Removing one workspace layer will save approx 2 hours of build time on fresh builds
- Removing one coreboot version will save us approx 2 hours of build time on fresh builds
- KGPE-D16 will stay to coreboot 4.11 until forward notice.
- All other board configs SHOULD be built on latest coreboot versions
- all: coreboot NO_POST for all boards
- all: coreboot NO_GFX_INIT (linux payload does the graphic init)
- all: coreboot TPM_MEASURED_BOOT (no more patches under Heads for measured boot)
- all: coreboot DRIVERS_PS2_KEYBOARD (fixes no keyboard on soft reboot and potentially xx30t xx20t fix for random raw keyboard (to be tested)
- all: coreboot removal of DEFAULT_CONSOLE_LOGLEVEL_5 under some boards
- all: coreboot removal of "loglevel=3" under some linux command line options booting Heads kernel
- all: coreboot removal of DEBUG_SMM_RELOCATION (unneeded)
- all: coreboot INCLUDE_CONFIG_FILE and COLLECT_TIMESTAMPS for all boards
- all: coreboot CONSOLE_SERIAL present on all boards
- all: coreboot add VBT
- all: board configs switch to cryptsetup2
xx20 hotp-maximized boards:
- removal of dropbear (not enough space to have htop + dropbear)
txx0 boards coreboot:
- USE_OPTION_TABLE and STATIC_OPTION_TABLE added (todo: check T430 boards optimization and find issue/PR and ammend this commit)
Added note to KGPE-D16 configs about the current microcode bug, why microcode is not included and encouraging AMD Opteron 6300 series users to make sure their operating system loads microcode.
* xx30-*-maximized: update flashrom options removing --ifd bios option, keeping whole flash of rom internally. WARNING: ifd needs to be initially unlocked through ifdtool -u on 8mb bottom SPI backup. YOU CANNOT COME FROM 1VYRAIN. IF COMING FROM SKULLS, YOU MUST HAVE RAN OPTIONAL -u OPTION FROM SKULLS. PLEASE UPGRADE ONLY AFTER HAVING A PHYSICAL BACKUP OF BOTH SPI FLASH CHIPS. MORE INFORMATION UNDER https://github.com/osresearch/heads/pull/703. This will guarantee that future flash of produced rom will reflash the ROM totally, where heads make sure of adding users customizations (public key, /etc/config.user) when internally flashed. Unfortunately, if you flash externally, you will have to reinject your public key and readd /etc/config customizations.
* Adding generated bincfg coreboot 4.8.1 patch (merged under coreboot 4.13 and backported here to 4.8.1), resulting in gbe.bin under blobs/xx30/gbe.bin and instructions to replicate in README prior of automation (under repo). Note that MAC under gbe.bin is fixed to DE:AD:C0:FF:EE unless extract.sh script is ran on external backup to keep current user's MAC (Thanks to @Thrilleratplay's contribution!)
* xx30 blobs: add two blobs management scripts for xx30: extract from local backup/download+neuter ME
extract.sh: extract from external backup: gbe.bin, neuter under me.bin and maximize BIOS+reduce ME regions under unlocked ifd.bin.
download_clean_me.sh: download and verify Lenovo latest ME version from website, and drop me.bin in place.
Note: me.bin is 98kb, containing only BUP and ROMP partitions which cannot be modified nor deleted else computer won't boot. As a result, BIOS region is maximized in ifd.bin to 11.5mb and coreboot config takes advantage of that freed space.
* CircleCI: xx30-*-maximized additional step to call download_clean_me.sh prior of building boards so that me.bin is dopped in place. This should be done by users prior of building xx30-*-maximized boards locally, which is imitated in CircleCI builds (look at .circleci/config.yaml for innoextract host added dependency and board buildings. Results on github for each commit).
cp config/linux.. ./build/linux*/.config
cd build/linux*
make savedefconfig
cp defconfig ../../config/linux..
Resulting in only linux-kgpe-d16_workstation.config being updated.
For KGPE-D16 workstation boards:
Remove `console=tty0` from `CONFIG_BOOT_KERNEL_ADD` as was blocking Qubes graphical installer (CLI installer was launched).
Comment out `export CONFIG_BOOT_KERNEL_REMOVE="plymouth.ignore-serial-consoles"` to provide a more desktop like experience.
Removed 0001-cpu-x86-smm-Use-PRIxPTR-to-print-uintptr_t.patch as already exists as 0000-cpu-x86-smm-Use-PRIxPTR-to-print-uintptr_t.patch
Added 0020-kgpe-d16_measured-boot-support.patch for coreboot 4.11
Fix TPM errors when microcode is measured by initialising TPM earlier and loading the microcode later.
Thanks to Michał Żygowski <miczyg1> for condition suggestion: `if (CONFIG(MEASURED_BOOT) && CONFIG(LPC_TPM) && boot_cpu())`
Locate bootblock location and size with CBFS API. Credit to: Michał Żygowski <miczyg1>
Bring patches/coreboot-4.11 on par with master
Removed patches/coreboot-4.11/0020-kgpe-d16-vboot.patch
Removed Vboot options from KGPE-D16 coreboot configs
Enabled TPM in kgpe-d16 board configs
Enabled measured boot in kgpe-d16 coreboot configs.
Added support for video cards that require nouveau, radeon and amdgpu drivers in linux-kgpe-d16_workstation.config
`nouveau.config=NvForcePost=1` to be added to kexec'd kernels for better Nvidia card support.
Changing CONFIG_USB_BOOT_DEV to sdc1, adding back CONFIG_BOOT_STATIC_IP to 192.168.2.3, adding dual console to OpenBMC and tty0 in attempt to have QubesOS graphic installer which complains with no networking when attempting to start VNC
Adding dual console to OpenBmc and tty0
putting kgpe-d16-coreboot.conf in defconfig format
NO_HZ wasn't included in kernel config. Adding it.
Wasn't able to have both console firing up QubesOS gui installer, complaining about hvc1 console errors. Splitting up Workstation and server config. This one works for Worstation
Removing serial configuration and static IP stuff since we have a workstation here.
Seperate Workstation and Server board configurations until dual console truely works through QubesOS gui installation. kgpe-d16 board config removed until then.
Placing files in good directories
Corrrect flashrom options for kgpe-d16 server and workstation boards
kgpe-d16 linux: NO_HZ_IDLE instead of NO_HZ
kgpe-d16: seperate board for workstation to be AST and gui-init based, while kgpe-d16-> kgpe-d16_server
kgpe-d16_server: boots, shows ASpeed text on VGA, controllable through BMC via SSH.
kgpe-d16_workstation on ASpeed console. WIP. (Includes CIs configs to build server and workstation)
kgpe-d16_workstation in defconfig format
kgpe-d16 boards: pass from GPG to GPG2 board definitions
kgpe-d16_workstation : Adding Cairo and FbWhpitail in board config for gui-init to work in FB mode
kgpe-d16: removing plymouth.ignore-serial-consoles to fix server terminal output
kgpe-d16: bring par with staging branch https://gitlab.com/tlaurion/heads/commits/kgpe-d16_staging
kgpe-d16 : expressively export CONFIG_TPM=n
kgpe-d16_wokstation gui-init variables were missing
kgpe-d16 boards: add CONFIG_LINUX_USB_COMPANION_CONTROLLER so that usb is recognized
linux-kgpe-d16*: add support for Pike
kgpe-d16_workstation-usb_keyboard board support addition
kgpe-d16_server-whiptail: Add board and dependencies to have gui-init in whiptail (console mode, not FbWhiptail based
GitlabCI: kgpe-d16 fixes and upstream merge of change
kgpe-d16* board: add statement to fixate coreboot version to 4.8.1 for the moment
kgpe-d16: add missing config/linux-kgpe-d16_server-whiptail.config file
KGPE-D16: community work migration to coreboot 4.11 to fix issue #740
KGPE-D16 boards: Adding VBOOT+measured boot, musl-cross patch and 4.11 patch brought up per https://github.com/osresearch/heads/pull/709
kgpe-d16* boards: add VBOOT Kconfig patch per @miczyg1 recommendation under https://github.com/osresearch/heads/pull/795#issuecomment-671214637
KGPE-D16* coreboot configs: Add S3NV as a Runtime data whitelist (so that it is not measured at term) per @miczyg1 recommendation under https://github.com/osresearch/heads/pull/795#issuecomment-671214637
kgpe-d16 coreboot 4.11: add https://review.coreboot.org/c/coreboot/+/36908 patch
kgpe-d16 boards: add Linux kernel version where missing.
CircleCI: Add debug output on fail for kgpe-d16 board builds to bring par with upstream after rebasing on master
coreboot module: typo correction (tabs vs spaces)
CircleCI: trying to address "g++: fatal error: Killed signal terminated program cc1plus." happening under coreboot 4.11 and coreboot 4.12 builds
CircleCI: remove past addition to test recommendation from CircleCI: "resource_class: large"
CircleCi: Ok.... lets output dmesg content prior of other logs.... I'm out of ideas. Next step, ask CircleCI for support
At this stage:
- job's "make --load" is supposed to guarantee that the number of thread doesn't exhaust pass of a load of 2 (medium, free class, CircleCI has 32 cores so possibility of a load of 32)
- "--max_old_space_size=4096" in CircleCI environement is supposed to limit memory consumption to 4096Mb of memory, the max of a medium class free tier CircleCI node
CircleCI: remove verbose build (no more V=1), in case of failed build, find all logs modified in last minute and output each of them on console.
coreboot module: implement load average respect inside of problematic CI build for coreboot 4.11+ being killed in the action (32 cores with 4Gb ram get gcc OOM)
coreboot module: replace nproc by number of Gb actually available as number of CPUs, since each thread is expected to have 1Gb of ram.
CircleCI & coreboot config: fix merge conflict rebasing on master
coreboot 4.11 kgpe-d16 vboot patches addendum, credits goes to @Tonux599
Fix merge conflicts and make sure all boards are inside of CircleCI builds. PoC build for #867
* modules/linux: add support for building with kernel 5.4.69
Add support to module, port patches from 4.19.139.
Needed for newer platforms not supported by 4.19 kernel.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* CircleCI: add rysnc dependency for building kernel 5.x
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* Migrate all Librem boards to kernel 5.x, common config
Update linux-librem_common.config from 4.x to 5.x, and add
CONFIG items needed to support the librem_l1um (AST DRM drivers,
serial port output).
Tested on Librem 13v4, Librem Mini, and Librem Server L1UM.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* config/coreboot-*: drop CONFIG_LOCALVERSION
Will be injected as part of the build using $(HEADS_GIT_VERSION)
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* modules/coreboot: inject $(HEADS_GIT_VERSION) as CONFIG_LOCALVERSION
Needed for fwupd to handle board updates
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* modules/coreboot: override SMBIOS ProductName with $(BOARD)
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* Use $(BOARD)-$(HEADS_GIT_VERSION) as basis for output filename
makes builds uniquely identifiable based on board and version.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
Increase size of CBFS to 0xC00000 (from 0x800000) to accomodate
newer/larger kernels.
Update purism-blobs module so an update/modified IFD and smaller
ME blob are used.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* x230-hotp-verification: revert to coreboot "CONFIG_CBFS_SIZE=0x700000" by disabling board "CONFIG_DROPBEAR=y" and "CONFIG_LINUX_E1000E" to save space per @alex-nitrokey test under #770 to fix#608
* x230-htop-verification board: add clarifications on x230 board differences. Fixes#737#770#608
* X230 board & coreboot config: Fix x230 board, removing dropbear and e1000e driver.
* t430: board and coreboot config par with x230 to circumvent CBFS linked suspend/resume issues.
* add x230-nkstorecli board;
* add modules: nkstorecli, libnk, libhidapi-libusb
* version bump nkstorecli; related minor in libnk
* upd. libnk module version bump to 3.6; remove 3.5 patch
* modules/coreboot: add option to use coreboot 4.11
Port patches from coreboot 4.8.1 to 4.11:
* 0000-measure-boot -> 0001
* 0010-cross-compiler-support
All other patches for coreboot 4.8.1 have either already been
integrated, or are for platforms which do not need to be migrated
to coreboot 4.11 (they will move to 4.12 or newer).
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* patches/coreboot-4.11: Add Broadwell-DE platform patch
Add a patch for FSP Broadwell-DE to make use of Heads' measured boot.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* patches/coreboot-4.11: Add patch to read serial # from CBFS
Will be used by multiple Librem boards.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* patches/coreboot-4.11: add board support for Librem Server L1UM
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* Librem Server L1UM: add new board
Add board config, coreboot config, kernel config files.
Add conditional purism-blobs dependency to coreboot-4.11 module.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* flash.sh: add special handling for librem_l1um board
Add support for persisting PCIe config via PCHSTRP9 in flash descriptor.
This is needed to support multiple variants of the L1UM server which
use the same firmware but differ in PCIe lane configuration via the
PCH straps configuration in the flash descriptor.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* patches/coreboot-4.11: Add 'Use PRIxPTR to print uintptr_t' patch
Cherry-picked from upstream coreboot (post-4.11), fixes compilation issue.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* CircleCI: add target to build board librem_l1um
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
Set the kernel video mode for the internal display to 1080p,
as the native panel resolution of 2160p is difficult to read.
A recent update to fbwhiptail allows the GUI to make use of the
scaled resolution as well, provided it is set via kernel param.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* patches/coreboot-4.12: add cross-compiler support patch
Ported from coreboot-4.8.1, re-exported via `git diff`
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* modules/coreboot: use musl-cross-make to build
revert toolchain bits to pre-4.12 addition
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* config/coreboot-librem_mini: use CONFIG_ANY_TOOLCHAIN
Needed since coreboot 4.12 now built with musl-cross-make
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
There's only one Librem Mini board, it doesn't use a TPM,
no reason to unnecesarily lengthen the board name.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* CircleCI: readd librem_mini while making sure that if a board build fails, all logfile modified in the last minute are outputted on the CircleCI console prior to really failing and exiting
* librem_mini-NoTPM: addition of board config, distinctive coreboot config (required per Heads build system) to construct a ROM without TPM requirement.
* librem_mini: deletion of board and coreboot relative config, keeping librem_mini-NoTPM and coreboot config only. Removed librem_mini board build under CircleCI, keeping only librem_mini-NoTPM
* patches/coreboot-4.12: Add patch for Cannonlake ME status
Add patch print ME status regardless of enablement state
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* modules: add purism-blobs module
Rather than require users to manually run a script to download the required
blobs to build Purism Librem boards, automate it so the correct version
is automatically downloaded/extracted. Restrict to coreboot 4.12 for now
since 4.8.1 still needs FSP blobs, which are not in module.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* configs/linux-librem13v2: unset CONFIG_RETPOLINE
Fixes compilation issue with newer kernels, ignored by older ones
which don't need it
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* Add new board: Librem Mini
Add Librem Mini board patch for coreboot 4.12, board config and
coreboot config. Continue reusing existing librem13v2 Linux config,
same as all other Librem boards currently. Use new purism-blobs module.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* board/librem*: rename for consistency
Use 'librem_<board>' notation for consistency across all models.
Rename linux config file since used by multiple Librem models.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* CircleCI: add librem_mini board to test
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
* Add support for the Lenovo ThinkPad T420 and X220.
* Fix the autodetection of ifdtool and me_cleaner.
* Enable FBWhiptail mode for X220 and T420
* Decreased CBFS size to fix 50 seconds boot delay problems
Add ability to change CMOS values by genning SMBIOS tables and using the values from stock bios, this allows for editing of SMBIOS values to change things such as VRAM allocation, FN and CTRL key swap etc
Disabling IOMMU on the iGPU for Heads (mostly) eliminates
display corruption when kexec'ing to new kernel (and has no effect
on iGPU/IOMMU for kexec'ed kernel)
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
Drop coreinto/memtest secondary payloads as they are not
usable with Linux as primary payload. Leftover copy-pasta
from original SeaBIOS configs.
Signed-off-by: Matt DeVillier <matt.devillier@puri.sm>
Remove debug symbols and dynamic debug support from Linux. This reduces
our resulting bzImage by 100K.
This should help when size becomes even more limited, see #562
This changes Heads' bootscript for the x230 to gui-init and adds config
options needed for it. The config is very similar to the librem13v2 config.
My comparison of startup-time from a power-button press shows 2.5 seconds
more with these changes applied.
That said, the experience is smooth, the GUI is beautiful and easier to use
than the shell and text menu, especially during setup. That's what we
buy with startup time here.
The Librem coreboot is labeled with the current version and is visible
from dmidecode and is supposed to reflect the current version of
coreboot, however it was out of date and reflected 4.7 when Heads has
moved on to 4.8.1.
I've also added a simple change to further simplify onboarding by
warning users who have Librem Key configured when they boot without it
being inserted.
This reduces the amount of noise in the Linux kernel config files
by only storing the differences from the stock configuration.
It adds a new makefile target 'linux.saveconfig' to convert the
build tree's .config file into config/linux-linuxboot.config.
Adding the VBT file makes it available through some ACPI memory area
and apparently the VBT contains the information needed by the i915 driver
in order to figure out how to control the screen's backlight.
Without the VBT, we can't control the screen backlight with Fn-F5/Fn-F6
anymore.
Fixes access to the EC through the Index I/O interface
Fixes AC and DC LoadLine values to avoid overheating problems
Fix Turbo mode value from EC
Change version name to have '-heads' suffix
By enabling Pass-through iommu, it fixes the GPU glitching issues
we've had with IOMMU, and it also allows us to boot a target kernel
without having to give it intel_iommu=igfx_off as argument.
