Use attack vector controls to determine if MDS mitigation is required.
The global mitigations=off command now simply disables all attack vectors
so explicit checking of mitigations=off is no longer needed.
If cross-thread attack mitigations are required, disable SMT.
Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250707183316.1349127-6-david.kaplan@amd.com
ARCH_HAS_CPU_ATTACK_VECTORS should be set for architectures which implement
the new attack-vector based controls for CPU mitigations. If an arch does
not support attack-vector based controls then an attempt to use them
results in a warning.
Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250707183316.1349127-4-david.kaplan@amd.com
Define 4 new attack vectors that are used for controlling CPU speculation
mitigations. These may be individually disabled as part of the
mitigations= command line. Attack vector controls are combined with global
options like 'auto' or 'auto,nosmt' like 'mitigations=auto,no_user_kernel'.
The global options come first in the mitigations= string.
Cross-thread mitigations can either remain enabled fully, including
potentially disabling SMT ('auto,nosmt'), remain enabled except for
disabling SMT ('auto'), or entirely disabled through the new
'no_cross_thread' attack vector option.
The default settings for these attack vectors are consistent with existing
kernel defaults, other than the automatic disabling of VM-based attack
vectors if KVM support is not present.
Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250707183316.1349127-3-david.kaplan@amd.com
Document the 5 new attack vector command line options, how they
interact with existing vulnerability controls, and recommendations on when
they can be disabled.
Note that while mitigating against untrusted userspace requires both
user-to-kernel and user-to-user protection, these are kept separate. The
kernel can control what code executes inside of it and that may affect the
risk associated with vulnerabilities especially if new kernel mitigations
are implemented. The same isn't typically true of userspace.
In other words, the risk associated with user-to-user or guest-to-guest
attacks is unlikely to change over time. While the risk associated with
user-to-kernel or guest-to-host attacks may change. Therefore, these
controls are separated.
Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250709155731.3279419-1-david.kaplan@amd.com
SRSO microcode only exists for Zen3/Zen4 CPUs. For those CPUs, the microcode
is required for any mitigation other than Safe-RET to be effective. Safe-RET
can still protect user->kernel and guest->host attacks without microcode.
Clarify this in the code and ensure that SRSO_MITIGATION_UCODE_NEEDED is
selected for any mitigation besides Safe-RET if the required microcode isn't
present.
Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250625155805.600376-4-david.kaplan@amd.com
After a recent restructuring of the ITS mitigation, RSB stuffing can no longer
be enabled in eIBRS+Retpoline mode. Before ITS, retbleed mitigation only
allowed stuffing when eIBRS was not enabled. This was perfectly fine since
eIBRS mitigates retbleed.
However, RSB stuffing mitigation for ITS is still needed with eIBRS. The
restructuring solely relies on retbleed to deploy stuffing, and does not allow
it when eIBRS is enabled. This behavior is different from what was before the
restructuring. Fix it by allowing stuffing in eIBRS+retpoline mode also.
Fixes: 61ab72c2c6 ("x86/bugs: Restructure ITS mitigation")
Closes: https://lore.kernel.org/lkml/20250519235101.2vm6sc5txyoykb2r@desk/
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250611-eibrs-fix-v4-7-5ff86cac6c61@linux.intel.com
The purpose of the warning is to prevent an unexpected change to the return
thunk mitigation. However, there are legitimate cases where the return
thunk is intentionally set more than once. For example, ITS and SRSO both
can set the return thunk after retbleed has set it. In both the cases
retbleed is still mitigated.
Replace the warning with an info about the active return thunk.
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250611-eibrs-fix-v4-3-5ff86cac6c61@linux.intel.com
The retbleed select function leaves the mitigation to AUTO in some cases.
Moreover, the update function can also set the mitigation to AUTO. This
is inconsistent with other mitigations and requires explicit handling of
AUTO at the end of update step.
Make sure a mitigation gets selected in the select step, and do not change
it to AUTO in the update step. When no mitigation can be selected leave it
to NONE, which is what AUTO was getting changed to in the end.
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250611-eibrs-fix-v4-1-5ff86cac6c61@linux.intel.com
Move the VERW clearing before the MONITOR so that VERW doesn't disarm it
and the machine never enters C1.
Original idea by Kim Phillips <kim.phillips@amd.com>.
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Pull Kbuild fixes from Masahiro Yamada:
- Move warnings about linux/export.h from W=1 to W=2
- Fix structure type overrides in gendwarfksyms
* tag 'kbuild-fixes-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
gendwarfksyms: Fix structure type overrides
kbuild: move warnings about linux/export.h from W=1 to W=2
As we always iterate through the entire die_map when expanding
type strings, recursively processing referenced types in
type_expand_child() is not actually necessary. Furthermore,
the type_string kABI rule added in commit c9083467f7
("gendwarfksyms: Add a kABI rule to override type strings") can
fail to override type strings for structures due to a missing
kabi_get_type_string() check in this function.
Fix the issue by dropping the unnecessary recursion and moving
the override check to type_expand(). Note that symbol versions
are otherwise unchanged with this patch.
Fixes: c9083467f7 ("gendwarfksyms: Add a kABI rule to override type strings")
Reported-by: Giuliano Procida <gprocida@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull block fixes from Jens Axboe:
- Fix for a deadlock on queue freeze with zoned writes
- Fix for zoned append emulation
- Two bio folio fixes, for sparsemem and for very large folios
- Fix for a performance regression introduced in 6.13 when plug
insertion was changed
- Fix for NVMe passthrough handling for polled IO
- Document the ublk auto registration feature
- loop lockdep warning fix
* tag 'block-6.16-20250614' of git://git.kernel.dk/linux:
nvme: always punt polled uring_cmd end_io work to task_work
Documentation: ublk: Separate UBLK_F_AUTO_BUF_REG fallback behavior sublists
block: Fix bvec_set_folio() for very large folios
bio: Fix bio_first_folio() for SPARSEMEM without VMEMMAP
block: use plug request list tail for one-shot backmerge attempt
block: don't use submit_bio_noacct_nocheck in blk_zone_wplug_bio_work
block: Clear BIO_EMULATES_ZONE_APPEND flag on BIO completion
ublk: document auto buffer registration(UBLK_F_AUTO_BUF_REG)
loop: move lo_set_size() out of queue freeze
Pull io_uring fixes from Jens Axboe:
- Fix for a race between SQPOLL exit and fdinfo reading.
It's slim and I was only able to reproduce this with an artificial
delay in the kernel. Followup sparse fix as well to unify the access
to ->thread.
- Fix for multiple buffer peeking, avoiding truncation if possible.
- Run local task_work for IOPOLL reaping when the ring is exiting.
This currently isn't done due to an assumption that polled IO will
never need task_work, but a fix on the block side is going to change
that.
* tag 'io_uring-6.16-20250614' of git://git.kernel.dk/linux:
io_uring: run local task_work from ring exit IOPOLL reaping
io_uring/kbuf: don't truncate end buffer for multiple buffer peeks
io_uring: consistently use rcu semantics with sqpoll thread
io_uring: fix use-after-free of sq->thread in __io_uring_show_fdinfo()
Pull Rust fix from Miguel Ojeda:
- 'hrtimer': fix future compile error when the 'impl_has_hr_timer!'
macro starts to get called
* tag 'rust-fixes-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
rust: time: Fix compile error in impl_has_hr_timer macro
Pull misc fixes from Andrew Morton:
"9 hotfixes. 3 are cc:stable and the remainder address post-6.15 issues
or aren't considered necessary for -stable kernels. Only 4 are for MM"
* tag 'mm-hotfixes-stable-2025-06-13-21-56' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
mm: add mmap_prepare() compatibility layer for nested file systems
init: fix build warnings about export.h
MAINTAINERS: add Barry as a THP reviewer
drivers/rapidio/rio_cm.c: prevent possible heap overwrite
mm: close theoretical race where stale TLB entries could linger
mm/vma: reset VMA iterator on commit_merge() OOM failure
docs: proc: update VmFlags documentation in smaps
scatterlist: fix extraneous '@'-sign kernel-doc notation
selftests/mm: skip failed memfd setups in gup_longterm
Pull SCSI fixes from James Bottomley:
"All fixes for drivers.
The core change in the error handler is simply to translate an ALUA
specific sense code into a retry the ALUA components can handle and
won't impact any other devices"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: error: alua: I/O errors for ALUA state transitions
scsi: storvsc: Increase the timeouts to storvsc_timeout
scsi: s390: zfcp: Ensure synchronous unit_add
scsi: iscsi: Fix incorrect error path labels for flashnode operations
scsi: mvsas: Fix typos in per-phy comments and SAS cmd port registers
scsi: core: ufs: Fix a hang in the error handler
Pull drm fixes from Dave Airlie:
"Quiet week, only two pull requests came my way, xe has a couple of
fixes and then a bunch of fixes across the board, vc4 probably fixes
the biggest problem:
vc4:
- Fix infinite EPROBE_DEFER loop in vc4 probing
amdxdna:
- Fix amdxdna firmware size
meson:
- modesetting fixes
sitronix:
- Kconfig fix for st7171-i2c
dma-buf:
- Fix -EBUSY WARN_ON_ONCE in dma-buf
udmabuf:
- Use dma_sync_sgtable_for_cpu in udmabuf
xe:
- Fix regression disallowing 64K SVM migration
- Use a bounce buffer for WA BB"
* tag 'drm-fixes-2025-06-14' of https://gitlab.freedesktop.org/drm/kernel:
drm/xe/lrc: Use a temporary buffer for WA BB
udmabuf: use sgtable-based scatterlist wrappers
dma-buf: fix compare in WARN_ON_ONCE
drm/sitronix: st7571-i2c: Select VIDEOMODE_HELPERS
drm/meson: fix more rounding issues with 59.94Hz modes
drm/meson: use vclk_freq instead of pixel_freq in debug print
drm/meson: fix debug log statement when setting the HDMI clocks
drm/vc4: fix infinite EPROBE_DEFER loop
drm/xe/svm: Fix regression disallowing 64K SVM migration
accel/amdxdna: Fix incorrect PSP firmware size
In preparation for needing to shift NVMe passthrough to always use
task_work for polled IO completions, ensure that those are suitably
run at exit time. See commit:
9ce6c9875f ("nvme: always punt polled uring_cmd end_io work to task_work")
for details on why that is necessary.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently NVMe uring_cmd completions will complete locally, if they are
polled. This is done because those completions are always invoked from
task context. And while that is true, there's no guarantee that it's
invoked under the right ring context, or even task. If someone does
NVMe passthrough via multiple threads and with a limited number of
poll queues, then ringA may find completions from ringB. For that case,
completing the request may not be sound.
Always just punt the passthrough completions via task_work, which will
redirect the completion, if needed.
Cc: stable@vger.kernel.org
Fixes: 585079b6e4 ("nvme: wire up async polling for io passthrough commands")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull ACPI fixes from Rafael Wysocki:
"These fix an ACPI APEI error injection driver failure that started to
occur after switching it over to using a faux device, address an EC
driver issue related to invalid ECDT tables, clean up the usage of
mwait_idle_with_hints() in the ACPI PAD driver, add a new IRQ override
quirk, and fix a NULL pointer dereference related to nosmp:
- Update the faux device handling code in the driver core and address
an ACPI APEI error injection driver failure that started to occur
after switching it over to using a faux device on top of that (Dan
Williams)
- Update data types of variables passed as arguments to
mwait_idle_with_hints() in the ACPI PAD (processor aggregator
device) driver to match the function definition after recent
changes (Uros Bizjak)
- Fix a NULL pointer dereference in the ACPI CPPC library that occurs
when nosmp is passed to the kernel in the command line (Yunhui Cui)
- Ignore ECDT tables with an invalid ID string to prevent using an
incorrect GPE for signaling events on some systems (Armin Wolf)
- Add a new IRQ override quirk for MACHENIKE 16P (Wentao Guan)"
* tag 'acpi-6.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI: resource: Use IRQ override on MACHENIKE 16P
ACPI: EC: Ignore ECDT tables with an invalid ID string
ACPI: CPPC: Fix NULL pointer dereference when nosmp is used
ACPI: PAD: Update arguments of mwait_idle_with_hints()
ACPI: APEI: EINJ: Do not fail einj_init() on faux_device_create() failure
driver core: faux: Quiet probe failures
driver core: faux: Suppress bind attributes
Pull power management fixes from Rafael Wysocki:
"These fix the cpupower utility installation, fix up the recently added
Rust abstractions for cpufreq and OPP, restore the x86 update
eliminating mwait_play_dead_cpuid_hint() that has been reverted during
the 6.16 merge window along with preventing the failure caused by it
from happening, and clean up mwait_idle_with_hints() usage in
intel_idle:
- Implement CpuId Rust abstraction and use it to fix doctest failure
related to the recently introduced cpumask abstraction (Viresh
Kumar)
- Do minor cleanups in the `# Safety` sections for cpufreq
abstractions added recently (Viresh Kumar)
- Unbreak cpupower systemd service units installation on some systems
by adding a unitdir variable for specifying the location to install
them (Francesco Poli)
- Eliminate mwait_play_dead_cpuid_hint() again after reverting its
elimination during the 6.16 merge window due to a problem with
handling "dead" SMT siblings, but this time prevent leaving them in
C1 after initialization by taking them online and back offline when
a proper cpuidle driver for the platform has been registered
(Rafael Wysocki)
- Update data types of variables passed as arguments to
mwait_idle_with_hints() to match the function definition after
recent changes (Uros Bizjak)"
* tag 'pm-6.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
rust: cpu: Add CpuId::current() to retrieve current CPU ID
rust: Use CpuId in place of raw CPU numbers
rust: cpu: Introduce CpuId abstraction
intel_idle: Update arguments of mwait_idle_with_hints()
cpufreq: Convert `/// SAFETY` lines to `# Safety` sections
cpupower: split unitdir from libdir in Makefile
Reapply "x86/smp: Eliminate mwait_play_dead_cpuid_hint()"
ACPI: processor: Rescan "dead" SMT siblings during initialization
intel_idle: Rescan "dead" SMT siblings during initialization
x86/smp: PM/hibernate: Split arch_resume_nosmt()
intel_idle: Use subsys_initcall_sync() for initialization
Merge assorted ACPI updates for 6.16-rc2:
- Update data types of variables passed as arguments to
mwait_idle_with_hints() in the ACPI PAD (processor aggregator device)
driver to match the function definition after recent changes (Uros
Bizjak).
- Fix a NULL pointer dereference in the ACPI CPPC library that occurs
when nosmp is passed to the kernel in the command line (Yunhui Cui).
- Ignore ECDT tables with an invalid ID string to prevent using an
incorrect GPE for signaling events on some systems (Armin Wolf).
- Add a new IRQ override quirk for MACHENIKE 16P (Wentao Guan).
* acpi-pad:
ACPI: PAD: Update arguments of mwait_idle_with_hints()
* acpi-cppc:
ACPI: CPPC: Fix NULL pointer dereference when nosmp is used
* acpi-ec:
ACPI: EC: Ignore ECDT tables with an invalid ID string
* acpi-resource:
ACPI: resource: Use IRQ override on MACHENIKE 16P
Merge cpuidle updates for 6.16-rc2:
- Update data types of variables passed as arguments to
mwait_idle_with_hints() to match the function definition
after recent changes (Uros Bizjak).
- Eliminate mwait_play_dead_cpuid_hint() again after reverting its
elimination during the merge window due to a problem with handling
"dead" SMT siblings, but this time prevent leaving them in C1 after
initialization by taking them online and back offline when a proper
cpuidle driver for the platform has been registered (Rafael Wysocki).
* pm-cpuidle:
intel_idle: Update arguments of mwait_idle_with_hints()
Reapply "x86/smp: Eliminate mwait_play_dead_cpuid_hint()"
ACPI: processor: Rescan "dead" SMT siblings during initialization
intel_idle: Rescan "dead" SMT siblings during initialization
x86/smp: PM/hibernate: Split arch_resume_nosmt()
intel_idle: Use subsys_initcall_sync() for initialization
Merge a cpupower utility fix for 6.16-rc2 that unbreaks systemd service
units installation on some sysems (Francesco Poli).
* pm-tools:
cpupower: split unitdir from libdir in Makefile
Pull spi fixes from Mark Brown:
"A collection of driver specific fixes, most minor apart from the OMAP
ones which disable some recent performance optimisations in some
non-standard cases where we could start driving the bus incorrectly.
The change to the stm32-ospi driver to use the newer reset APIs is a
fix for interactions with other IP sharing the same reset line in some
SoCs"
* tag 'spi-fix-v6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
spi: spi-pci1xxxx: Drop MSI-X usage as unsupported by DMA engine
spi: stm32-ospi: clean up on error in probe()
spi: stm32-ospi: Make usage of reset_control_acquire/release() API
spi: offload: check offload ops existence before disabling the trigger
spi: spi-pci1xxxx: Fix error code in probe
spi: loongson: Fix build warnings about export.h
spi: omap2-mcspi: Disable multi-mode when the previous message kept CS asserted
spi: omap2-mcspi: Disable multi mode when CS should be kept asserted after message
Pull regulator fix from Mark Brown:
"One minor fix for a leak in the DT parsing code in the max20086 driver"
* tag 'regulator-fix-v6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
regulator: max20086: Fix refcount leak in max20086_parse_regulators_dt()
If an exiting non-autoreaping task has already passed exit_notify() and
calls handle_posix_cpu_timers() from IRQ, it can be reaped by its parent
or debugger right after unlock_task_sighand().
If a concurrent posix_cpu_timer_del() runs at that moment, it won't be
able to detect timer->it.cpu.firing != 0: cpu_timer_task_rcu() and/or
lock_task_sighand() will fail.
Add the tsk->exit_state check into run_posix_cpu_timers() to fix this.
This fix is not needed if CONFIG_POSIX_CPU_TIMERS_TASK_WORK=y, because
exit_task_work() is called before exit_notify(). But the check still
makes sense, task_work_add(&tsk->posix_cputimers_work.work) will fail
anyway in this case.
Cc: stable@vger.kernel.org
Reported-by: Benoît Sevens <bsevens@google.com>
Fixes: 0bdd2ed413 ("sched: run_posix_cpu_timers: Don't check ->exit_state, use lock_task_sighand()")
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
