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Mingcong Bai 677714d779 iommu/vt-d: Apply quirk_iommu_igfx for 8086:0044 (QM57/QS57) 
commit 2c8a7c66c9 upstream.

On the Lenovo ThinkPad X201, when Intel VT-d is enabled in the BIOS, the
kernel boots with errors related to DMAR, the graphical interface appeared
quite choppy, and the system resets erratically within a minute after it
booted:

DMAR: DRHD: handling fault status reg 3
DMAR: [DMA Write NO_PASID] Request device [00:02.0] fault addr 0xb97ff000
[fault reason 0x05] PTE Write access is not set

Upon comparing boot logs with VT-d on/off, I found that the Intel Calpella
quirk (`quirk_calpella_no_shadow_gtt()') correctly applied the igfx IOMMU
disable/quirk correctly:

pci 0000:00:00.0: DMAR: BIOS has allocated no shadow GTT; disabling IOMMU
for graphics

Whereas with VT-d on, it went into the "else" branch, which then
triggered the DMAR handling fault above:

... else if (!disable_igfx_iommu) {
	/* we have to ensure the gfx device is idle before we flush */
	pci_info(dev, "Disabling batched IOTLB flush on Ironlake\n");
	iommu_set_dma_strict();
}

Now, this is not exactly scientific, but moving 0x0044 to quirk_iommu_igfx
seems to have fixed the aforementioned issue. Running a few `git blame'
runs on the function, I have found that the quirk was originally
introduced as a fix specific to ThinkPad X201:

commit 9eecabcb9a ("intel-iommu: Abort IOMMU setup for igfx if BIOS gave
no shadow GTT space")

Which was later revised twice to the "else" branch we saw above:

- 2011: commit 6fbcfb3e46 ("intel-iommu: Workaround IOTLB hang on
  Ironlake GPU")
- 2024: commit ba00196ca4 ("iommu/vt-d: Decouple igfx_off from graphic
  identity mapping")

I'm uncertain whether further testings on this particular laptops were
done in 2011 and (honestly I'm not sure) 2024, but I would be happy to do
some distro-specific testing if that's what would be required to verify
this patch.

P.S., I also see IDs 0x0040, 0x0062, and 0x006a listed under the same
`quirk_calpella_no_shadow_gtt()' quirk, but I'm not sure how similar these
chipsets are (if they share the same issue with VT-d or even, indeed, if
this issue is specific to a bug in the Lenovo BIOS). With regards to
0x0062, it seems to be a Centrino wireless card, but not a chipset?

I have also listed a couple (distro and kernel) bug reports below as
references (some of them are from 7-8 years ago!), as they seem to be
similar issue found on different Westmere/Ironlake, Haswell, and Broadwell
hardware setups.

Cc: stable@vger.kernel.org
Fixes: 6fbcfb3e46 ("intel-iommu: Workaround IOTLB hang on Ironlake GPU")
Fixes: ba00196ca4 ("iommu/vt-d: Decouple igfx_off from graphic identity mapping")
Link: https://groups.google.com/g/qubes-users/c/4NP4goUds2c?pli=1
Link: https://bugs.archlinux.org/task/65362
Link: https://bbs.archlinux.org/viewtopic.php?id=230323
Reported-by: Wenhao Sun <weiguangtwk@outlook.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=197029
Signed-off-by: Mingcong Bai <jeffbai@aosc.io>
Link: https://lore.kernel.org/r/20250415133330.12528-1-jeffbai@aosc.io
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2025-05-09 09:50:34 +02:00
arch x86/boot/sev: Support memory acceptance in the EFI stub under SVSM 2025-05-09 09:50:32 +02:00
block mq-deadline: don't call req_get_ioprio from the I/O completion handler 2025-05-02 07:59:33 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: Kconfig - Select LIB generic option 2025-05-02 07:59:33 +02:00
Documentation bpf: Add namespace to BPF internal symbols 2025-05-02 07:59:04 +02:00
drivers iommu/vt-d: Apply quirk_iommu_igfx for 8086:0044 (QM57/QS57) 2025-05-09 09:50:34 +02:00
fs btrfs: fix COW handling in run_delalloc_nocow() 2025-05-09 09:50:30 +02:00
include netfilter: fib: avoid lookup if socket is available 2025-05-02 07:59:05 +02:00
init sched/isolation: Make CONFIG_CPU_ISOLATION depend on CONFIG_SMP 2025-05-02 07:59:21 +02:00
io_uring io_uring: always do atomic put from iowq 2025-05-02 07:59:21 +02:00
ipc ipc: fix memleak if msg_init_ns failed in create_ipc_ns 2024-12-05 14:03:02 +01:00
kernel tracing: Do not take trace_event_sem in print_event_fields() 2025-05-09 09:50:32 +02:00
lib crypto: lib/Kconfig - Hide arch options from user 2025-05-02 07:59:32 +02:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/memblock: repeat setting reserved region nid if array is doubled 2025-05-09 09:50:32 +02:00
net 9p/trans_fd: mark concurrent read and writes to p9_conn->err 2025-05-02 07:59:20 +02:00
rust rust: firmware: Use ffi::c_char type in FwFunc 2025-05-02 07:59:06 +02:00
samples tracing: Verify event formats that have "%*p.." 2025-05-02 07:58:52 +02:00
scripts objtool: Silence more KCOV warnings, part 2 2025-05-02 07:59:33 +02:00
security landlock: Prepare to add second errata 2025-04-20 10:15:56 +02:00
sound ALSA: usb-audio: Add second USB ID for Jabra Evolve 65 headset 2025-05-09 09:50:29 +02:00
tools objtool: Ignore end-of-section jumps for KCOV/GCOV 2025-05-02 07:59:33 +02:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-13 13:02:18 +01:00
virt KVM: Allow building irqbypass.ko as as module when kvm.ko is a module 2025-04-20 10:15:54 +02:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: enable Clippy's check-private-items 2025-03-13 13:01:42 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: add entry for the Rust alloc module 2025-03-13 13:01:47 +01:00
Makefile Linux 6.12.27 2025-05-05 11:00:29 +02:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.