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Vineeth Pillai (Google) 3cf1f23648 iommu/vt-d: Set INTEL_IOMMU_FLOPPY_WA depend on BLK_DEV_FD
[ Upstream commit cb3db5a39e ]

INTEL_IOMMU_FLOPPY_WA workaround was introduced to create direct mappings
for first 16MB for floppy devices as the floppy drivers were not using
dma apis. We need not do this direct map if floppy driver is not
enabled.

INTEL_IOMMU_FLOPPY_WA is generally not a good idea. Iommu will be
mapping pages in this address range while kernel would also be
allocating from this range(mostly on memory stress). A misbehaving
device using this domain will have access to the pages that the
kernel might be actively using. We noticed this while running a test
that was trying to figure out if any pages used by kernel is in iommu
page tables.

This patch reduces the scope of the above issue by disabling the
workaround when floppy driver is not enabled. But we would still need to
fix the floppy driver to use dma apis so that we need not do direct map
without reserving the pages. Or the other option is to reserve this
memory range in firmware so that kernel will not use the pages.

Fixes: d850c2ee5f ("iommu/vt-d: Expose ISA direct mapping region via iommu_get_resv_regions")
Fixes: 49a0429e53 ("Intel IOMMU: Iommu floppy workaround")
Signed-off-by: Vineeth Pillai (Google) <vineeth@bitbyteword.org>
Link: https://lore.kernel.org/r/20251002161625.1155133-1-vineeth@bitbyteword.org
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-12-18 14:03:06 +01:00
arch powerpc/64s/ptdump: Fix kernel_hash_pagetable dump for ISA v3.00 HPTE format 2025-12-18 14:03:04 +01:00
block block/blk-throttle: Fix throttle slice time for SSDs 2025-12-18 14:03:03 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: asymmetric_keys - prevent overflow in asymmetric_key_generate_id 2025-12-18 14:02:35 +01:00
Documentation dt-bindings: PCI: amlogic: Fix the register name of the DBI region 2025-12-18 14:02:54 +01:00
drivers
fs fs/ntfs3: Prevent memory leaks in add sub record 2025-12-18 14:03:05 +01:00
include bpf: Fix invalid prog->stats access when update_effective_progs fails 2025-12-18 14:03:04 +01:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/zcrx: call netdev_queue_get_dma_dev() under instance lock 2025-12-18 14:02:56 +01:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel bpf: Fix invalid prog->stats access when update_effective_progs fails 2025-12-18 14:03:04 +01:00
lib lib/vsprintf: Check pointer before dereferencing in time_and_date() 2025-12-18 14:02:58 +01:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm 8 hotfixes. 4 are cc:stable, 7 are against mm/. 2025-11-26 12:38:05 -08:00
net ipv6: clear RA flags when adding a static route 2025-12-18 14:03:05 +01:00
rust rust: Add -fno-isolate-erroneous-paths-dereference to bindgen_skip_c_flags 2025-11-10 08:37:06 +08:00
samples samples: work around glibc redefining some of our defines wrong 2025-11-21 09:29:02 -08:00
scripts kbuild: don't enable CC_CAN_LINK if the dummy program generates warnings 2025-12-18 14:03:01 +01:00
security ima: Attach CREDS_CHECK IMA hook to bprm_creds_from_file LSM hook 2025-12-18 14:02:27 +01:00
sound ALSA: hda/realtek: Add quirk for HP ProBook 450 G8 2025-11-26 07:26:56 +01:00
tools perf arm_spe: Fix memset subclass in operation 2025-12-18 14:03:06 +01:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM: guest_memfd: Remove bindings on memslot deletion when gmem is dying 2025-11-04 09:16:53 -08:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.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 MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap 8 hotfixes. 4 are cc:stable, 7 are against mm/. 2025-11-26 12:38:05 -08:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.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: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS soc: fixes for 6.18, part 4 2025-11-28 09:57:31 -08:00
Makefile Linux 6.18.1 2025-12-12 18:42:47 +01:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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.