__GFP_ATOMIC serves little purpose. Its main effect is to set
ALLOC_HARDER which adds a few little boosts to increase the chance of an
allocation succeeding, one of which is to lower the water-mark at which it
will succeed.
It is *always* paired with __GFP_HIGH which sets ALLOC_HIGH which also
adjusts this watermark. It is probable that other users of __GFP_HIGH
should benefit from the other little bonuses that __GFP_ATOMIC gets.
__GFP_ATOMIC also gives a warning if used with __GFP_DIRECT_RECLAIM.
There is little point to this. We already get a might_sleep() warning if
__GFP_DIRECT_RECLAIM is set.
__GFP_ATOMIC allows the "watermark_boost" to be side-stepped. It is
probable that testing ALLOC_HARDER is a better fit here.
__GFP_ATOMIC is used by tegra-smmu.c to check if the allocation might
sleep. This should test __GFP_DIRECT_RECLAIM instead.
This patch:
- removes __GFP_ATOMIC
- allows __GFP_HIGH allocations to ignore watermark boosting as well
as GFP_ATOMIC requests.
- makes other adjustments as suggested by the above.
The net result is not change to GFP_ATOMIC allocations. Other
allocations that use __GFP_HIGH will benefit from a few different extra
privileges. This affects:
xen, dm, md, ntfs3
the vermillion frame buffer
hibernation
ksm
swap
all of which likely produce more benefit than cost if these selected
allocation are more likely to succeed quickly.
[mgorman: Minor adjustments to rework on top of a series]
Link: https://lkml.kernel.org/r/163712397076.13692.4727608274002939094@noble.neil.brown.name
Link: https://lkml.kernel.org/r/20230113111217.14134-7-mgorman@techsingularity.net
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kmap() and kmap_atomic() have been deprecated. kmap_local_page() should
always be used in new code and the call sites of the two deprecated
functions should be converted. This latter task can lead to errors if it
is not carried out with the necessary attention to the context around and
between the maps and unmaps.
Therefore, add further information to the Highmem's documentation for the
purpose to make it clearer that (1) kmap() and kmap_atomic() must not any
longer be called in new code and (2) developers doing conversions from
kmap() amd kmap_atomic() are expected to take care of the context around
and between the maps and unmaps, in order to not break the code.
Relevant parts of this patch have been taken from messages exchanged
privately with Ira Weiny (thanks!).
[fmdefrancesco@gmail.com: merge two sentences into one, per Bagas]
Link: https://lkml.kernel.org/r/20230119123945.10471-1-fmdefrancesco@gmail.com
Link: https://lkml.kernel.org/r/20221207225308.8290-1-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
As Hardware Tag-Based KASAN is intended to be used in production, its
performance impact is crucial. As page_alloc allocations tend to be big,
tagging and checking all such allocations can introduce a significant
slowdown.
Add two new boot parameters that allow to alleviate that slowdown:
- kasan.page_alloc.sample, which makes Hardware Tag-Based KASAN tag only
every Nth page_alloc allocation with the order configured by the second
added parameter (default: tag every such allocation).
- kasan.page_alloc.sample.order, which makes sampling enabled by the first
parameter only affect page_alloc allocations with the order equal or
greater than the specified value (default: 3, see below).
The exact performance improvement caused by using the new parameters
depends on their values and the applied workload.
The chosen default value for kasan.page_alloc.sample.order is 3, which
matches both PAGE_ALLOC_COSTLY_ORDER and SKB_FRAG_PAGE_ORDER. This is
done for two reasons:
1. PAGE_ALLOC_COSTLY_ORDER is "the order at which allocations are deemed
costly to service", which corresponds to the idea that only large and
thus costly allocations are supposed to sampled.
2. One of the workloads targeted by this patch is a benchmark that sends
a large amount of data over a local loopback connection. Most multi-page
data allocations in the networking subsystem have the order of
SKB_FRAG_PAGE_ORDER (or PAGE_ALLOC_COSTLY_ORDER).
When running a local loopback test on a testing MTE-enabled device in sync
mode, enabling Hardware Tag-Based KASAN introduces a ~50% slowdown.
Applying this patch and setting kasan.page_alloc.sampling to a value
higher than 1 allows to lower the slowdown. The performance improvement
saturates around the sampling interval value of 10 with the default
sampling page order of 3. This lowers the slowdown to ~20%. The slowdown
in real scenarios involving the network will likely be better.
Enabling page_alloc sampling has a downside: KASAN misses bad accesses to
a page_alloc allocation that has not been tagged. This lowers the value
of KASAN as a security mitigation.
However, based on measuring the number of page_alloc allocations of
different orders during boot in a test build, sampling with the default
kasan.page_alloc.sample.order value affects only ~7% of allocations. The
rest ~93% of allocations are still checked deterministically.
Link: https://lkml.kernel.org/r/129da0614123bb85ed4dd61ae30842b2dd7c903f.1671471846.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Mark Brand <markbrand@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Charge moving mode in cgroup1 allows memory to follow tasks as they
migrate between cgroups. This is, and always has been, a questionable
thing to do - for several reasons.
First, it's expensive. Pages need to be identified, locked and isolated
from various MM operations, and reassigned, one by one.
Second, it's unreliable. Once pages are charged to a cgroup, there isn't
always a clear owner task anymore. Cache isn't moved at all, for example.
Mapped memory is moved - but if trylocking or isolating a page fails,
it's arbitrarily left behind. Frequent moving between domains may leave a
task's memory scattered all over the place.
Third, it isn't really needed. Launcher tasks can kick off workload tasks
directly in their target cgroup. Using dedicated per-workload groups
allows fine-grained policy adjustments - no need to move tasks and their
physical pages between control domains. The feature was never
forward-ported to cgroup2, and it hasn't been missed.
Despite it being a niche usecase, the maintenance overhead of supporting
it is enormous. Because pages are moved while they are live and subject
to various MM operations, the synchronization rules are complicated.
There are lock_page_memcg() in MM and FS code, which non-cgroup people
don't understand. In some cases we've been able to shift code and cgroup
API calls around such that we can rely on native locking as much as
possible. But that's fragile, and sometimes we need to hold MM locks for
longer than we otherwise would (pte lock e.g.).
Mark the feature deprecated. Hopefully we can remove it soon.
And backport into -stable kernels so that people who develop against
earlier kernels are warned about this deprecation as early as possible.
[akpm@linux-foundation.org: fix memory.rst underlining]
Link: https://lkml.kernel.org/r/Y5COd+qXwk/S+n8N@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull kvm fixes from Paolo Bonzini:
"ARM:
- Fix the PMCR_EL0 reset value after the PMU rework
- Correctly handle S2 fault triggered by a S1 page table walk by not
always classifying it as a write, as this breaks on R/O memslots
- Document why we cannot exit with KVM_EXIT_MMIO when taking a write
fault from a S1 PTW on a R/O memslot
- Put the Apple M2 on the naughty list for not being able to
correctly implement the vgic SEIS feature, just like the M1 before
it
- Reviewer updates: Alex is stepping down, replaced by Zenghui
x86:
- Fix various rare locking issues in Xen emulation and teach lockdep
to detect them
- Documentation improvements
- Do not return host topology information from KVM_GET_SUPPORTED_CPUID"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: x86/xen: Avoid deadlock by adding kvm->arch.xen.xen_lock leaf node lock
KVM: Ensure lockdep knows about kvm->lock vs. vcpu->mutex ordering rule
KVM: x86/xen: Fix potential deadlock in kvm_xen_update_runstate_guest()
KVM: x86/xen: Fix lockdep warning on "recursive" gpc locking
Documentation: kvm: fix SRCU locking order docs
KVM: x86: Do not return host topology information from KVM_GET_SUPPORTED_CPUID
KVM: nSVM: clarify recalc_intercepts() wrt CR8
MAINTAINERS: Remove myself as a KVM/arm64 reviewer
MAINTAINERS: Add Zenghui Yu as a KVM/arm64 reviewer
KVM: arm64: vgic: Add Apple M2 cpus to the list of broken SEIS implementations
KVM: arm64: Convert FSC_* over to ESR_ELx_FSC_*
KVM: arm64: Document the behaviour of S1PTW faults on RO memslots
KVM: arm64: Fix S1PTW handling on RO memslots
KVM: arm64: PMU: Fix PMCR_EL0 reset value
Pull documentation fixes from Jonathan Corbet:
"Three documentation fixes (or rather two and one warning):
- Sphinx 6.0 broke our configuration mechanism, so fix it
- I broke our configuration for non-Alabaster themes; Akira fixed it
- Deprecate Sphinx < 2.4 with an eye toward future removal"
* tag 'docs-6.2-fixes' of git://git.lwn.net/linux:
docs/conf.py: Use about.html only in sidebar of alabaster theme
docs: Deprecate use of Sphinx < 2.4.x
docs: Fix the docs build with Sphinx 6.0
Pull sound fixes from Takashi Iwai:
"This became a slightly big update, but it's more or less expected, as
the first batch after holidays.
All changes (but for the last two last-minute fixes) have been stewed
in linux-next long enough, so it's fairly safe to take:
- PCM UAF fix in 32bit compat layer
- ASoC board-specific fixes for Intel, AMD, Medathek, Qualcomm
- SOF power management fixes
- ASoC Intel link failure fixes
- A series of fixes for USB-audio regressions
- CS35L41 HD-audio codec regression fixes
- HD-audio device-specific fixes / quirks
Note that one SPI patch has been taken in ASoC subtree mistakenly, and
the same fix is found in spi tree, but it should be OK to apply"
* tag 'sound-6.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (39 commits)
ALSA: pcm: Move rwsem lock inside snd_ctl_elem_read to prevent UAF
ALSA: usb-audio: Fix possible NULL pointer dereference in snd_usb_pcm_has_fixed_rate()
ALSA: hda/realtek: Enable mute/micmute LEDs on HP Spectre x360 13-aw0xxx
ASoC: fsl-asoc-card: Fix naming of AC'97 CODEC widgets
ASoC: fsl_ssi: Rename AC'97 streams to avoid collisions with AC'97 CODEC
ALSA: hda/hdmi: Add a HP device 0x8715 to force connect list
ALSA: control-led: use strscpy in set_led_id()
ALSA: usb-audio: Always initialize fixed_rate in snd_usb_find_implicit_fb_sync_format()
ASoC: dt-bindings: qcom,lpass-tx-macro: correct clocks on SC7280
ASoC: dt-bindings: qcom,lpass-wsa-macro: correct clocks on SM8250
ASoC: qcom: Fix building APQ8016 machine driver without SOUNDWIRE
ALSA: hda: cs35l41: Check runtime suspend capability at runtime_idle
ALSA: hda: cs35l41: Don't return -EINVAL from system suspend/resume
ASoC: fsl_micfil: Correct the number of steps on SX controls
ALSA: hda/realtek: fix mute/micmute LEDs don't work for a HP platform
Revert "ALSA: usb-audio: Drop superfluous interface setup at parsing"
ALSA: usb-audio: More refactoring of hw constraint rules
ALSA: usb-audio: Relax hw constraints for implicit fb sync
ALSA: usb-audio: Make sure to stop endpoints before closing EPs
ALSA: hda - Enable headset mic on another Dell laptop with ALC3254
...
Pull power management fixes from Rafael Wysocki:
"These fix assorted issues in the ARM cpufreq drivers and in the AMD
P-state driver.
Specifics:
- Fix cpufreq policy reference counting in amd-pstate to prevent it
from crashing on removal (Perry Yuan)
- Fix double initialization and set suspend-freq for Apple's cpufreq
driver (Arnd Bergmann, Hector Martin)
- Fix reading of "reg" property, update cpufreq-dt's blocklist and
update DT documentation for Qualcomm's cpufreq driver (Konrad
Dybcio, Krzysztof Kozlowski)
- Replace 0 with NULL in the Armada cpufreq driver (Miles Chen)
- Fix potential overflows in the CPPC cpufreq driver (Pierre Gondois)
- Update blocklist for the Tegra234 Soc cpufreq driver (Sumit Gupta)"
* tag 'pm-6.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: amd-pstate: fix kernel hang issue while amd-pstate unregistering
cpufreq: armada-37xx: stop using 0 as NULL pointer
cpufreq: apple-soc: Switch to the lowest frequency on suspend
dt-bindings: cpufreq: cpufreq-qcom-hw: document interrupts
cpufreq: Add SM6375 to cpufreq-dt-platdev blocklist
cpufreq: Add Tegra234 to cpufreq-dt-platdev blocklist
cpufreq: qcom-hw: Fix reading "reg" with address/size-cells != 2
cpufreq: CPPC: Add u64 casts to avoid overflowing
cpufreq: apple: remove duplicate intializer
Pull drm fixes from Dave Airlie:
"There is a bit of a post-holiday build up here I expect, small fixes
across the board, amdgpu and msm being the main leaders, with others
having a few. One code removal patch for nouveau:
buddy:
- benchmark regression fix for top-down buddy allocation
panel:
- add Lenovo panel orientation quirk
ttm:
- fix kernel oops regression
amdgpu:
- fix missing fence references
- fix missing pipeline sync fencing
- SMU13 fan speed fix
- SMU13 fix power cap handling
- SMU13 BACO fix
- Fix a possible segfault in bo validation error case
- Delay removal of firmware framebuffer
- Fix error when unloading
amdkfd:
- SVM fix when clearing vram
- GC11 fix for multi-GPU
i915:
- Reserve enough fence slot for i915_vma_unbind_vsync
- Fix potential use after free
- Reset engines twice in case of reset failure
- Use multi-cast registers for SVG Unit registers
msm:
- display:
- doc warning fixes
- dt attribs cleanups
- memory leak fix
- error handing in hdmi probe fix
- dp_aux_isr incorrect signalling fix
- shutdown path fix
- accel:
- a5xx: fix quirks to be a bitmask
- a6xx: fix gx halt to avoid 1s hang
- kexec shutdown fix
- fix potential double free
vmwgfx:
- drop rcu usage to make code more robust
virtio:
- fix use-after-free in gem handle code
nouveau:
- drop unused nouveau_fbcon.c"
* tag 'drm-fixes-2023-01-13' of git://anongit.freedesktop.org/drm/drm: (35 commits)
drm: Optimize drm buddy top-down allocation method
drm/ttm: Fix a regression causing kernel oops'es
drm/i915/gt: Cover rest of SVG unit MCR registers
drm/nouveau: Remove file nouveau_fbcon.c
drm/amdkfd: Fix NULL pointer error for GC 11.0.1 on mGPU
drm/amd/pm/smu13: BACO is supported when it's in BACO state
drm/amdkfd: Add sync after creating vram bo
drm/i915/gt: Reset twice
drm/amdgpu: fix pipeline sync v2
drm/vmwgfx: Remove rcu locks from user resources
drm/virtio: Fix GEM handle creation UAF
drm/amdgpu: Fixed bug on error when unloading amdgpu
drm/amd: Delay removal of the firmware framebuffer
drm/amdgpu: Fix potential NULL dereference
drm/i915: Fix potential context UAFs
drm/i915: Reserve enough fence slot for i915_vma_unbind_async
drm: Add orientation quirk for Lenovo ideapad D330-10IGL
drm/msm/a6xx: Avoid gx gbit halt during rpm suspend
drm/msm/adreno: Make adreno quirks not overwrite each other
drm/msm: another fix for the headless Adreno GPU
...
Pull arm64 fixes from Will Deacon:
"Here's a sizeable batch of Friday the 13th arm64 fixes for -rc4. What
could possibly go wrong?
The obvious reason we have so much here is because of the holiday
season right after the merge window, but we've also brought back an
erratum workaround that was previously dropped at the last minute and
there's an MTE coredumping fix that strays outside of the arch/arm64
directory.
Summary:
- Fix PAGE_TABLE_CHECK failures on hugepage splitting path
- Fix PSCI encoding of MEM_PROTECT_RANGE function in UAPI header
- Fix NULL deref when accessing debugfs node if PSCI is not present
- Fix MTE core dumping when VMA list is being updated concurrently
- Fix SME signal frame handling when SVE is not implemented by the
CPU
- Fix asm constraints for cmpxchg_double() to hazard both words
- Fix build failure with stack tracer and older versions of Clang
- Bring back workaround for Cortex-A715 erratum 2645198"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: Fix build with CC=clang, CONFIG_FTRACE=y and CONFIG_STACK_TRACER=y
arm64/mm: Define dummy pud_user_exec() when using 2-level page-table
arm64: errata: Workaround possible Cortex-A715 [ESR|FAR]_ELx corruption
firmware/psci: Don't register with debugfs if PSCI isn't available
firmware/psci: Fix MEM_PROTECT_RANGE function numbers
arm64/signal: Always allocate SVE signal frames on SME only systems
arm64/signal: Always accept SVE signal frames on SME only systems
arm64/sme: Fix context switch for SME only systems
arm64: cmpxchg_double*: hazard against entire exchange variable
arm64/uprobes: change the uprobe_opcode_t typedef to fix the sparse warning
arm64: mte: Avoid the racy walk of the vma list during core dump
elfcore: Add a cprm parameter to elf_core_extra_{phdrs,data_size}
arm64: mte: Fix double-freeing of the temporary tag storage during coredump
arm64: ptrace: Use ARM64_SME to guard the SME register enumerations
arm64/mm: add pud_user_exec() check in pud_user_accessible_page()
arm64/mm: fix incorrect file_map_count for invalid pmd
msm-fixes for v6.3-rc4
Display Fixes:
- Fix the documentation for dpu_encoder_phys_wb_init() and
dpu_encoder_phys_wb_setup_fb() APIs to address doc warnings
- Remove vcca-supply and vdds-supply as mandatory for 14nm PHY and
10nm PHY DT schemas respectively as they are not present on some
SOCs using these PHYs
- Add the dsi-phy-regulator-ldo-mode to dsi-phy-28nm.yaml as it was
missed out during txt to yaml migration
- Remove operating-points-v2 and power-domain as a required property
for the DSI controller as thats not the case for every SOC
- Fix the description from display escape clock to display core
clock in the dsi controller yaml
- Fix the memory leak for mdp1-mem path for the cases when we return
early after failing to get mdp0-mem ICC paths for msm
- Fix error handling path in msm_hdmi_dev_probe() to release the phy
ref count when devm_pm_runtime_enable() fails
- Fix the dp_aux_isr() routine to make sure it doesnt incorrectly
signal the aux transaction as complete if the ISR was not an AUX
isr. This fixes a big hitter stability bug on chromebooks.
- Add protection against null pointer dereference when there is no
kms object as in the case of headless adreno GPU in the shutdown
path.
GPU Fixes:
- a5xx: fix quirks to actually be a bitmask and not overwrite each
other
- a6xx: fix gx halt sequence to avoid 1000ms hang on some devices
- kexec shutdown fix
- fix potential double free
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Rob Clark <robdclark@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/CAF6AEGv7=in_MHW3kdkhqh7ZFoVCmnikmr29YYHCXR=7aOEneg@mail.gmail.com
Pull networking fixes from Paolo Abeni:
"Including fixes from rxrpc.
The rxrpc changes are noticeable large: to address a recent regression
has been necessary completing the threaded refactor.
Current release - regressions:
- rxrpc:
- only disconnect calls in the I/O thread
- move client call connection to the I/O thread
- fix incoming call setup race
- eth: mlx5:
- restore pkt rate policing support
- fix memory leak on updating vport counters
Previous releases - regressions:
- gro: take care of DODGY packets
- ipv6: deduct extension header length in rawv6_push_pending_frames
- tipc: fix unexpected link reset due to discovery messages
Previous releases - always broken:
- sched: disallow noqueue for qdisc classes
- eth: ice: fix potential memory leak in ice_gnss_tty_write()
- eth: ixgbe: fix pci device refcount leak
- eth: mlx5:
- fix command stats access after free
- fix macsec possible null dereference when updating MAC security
entity (SecY)"
* tag 'net-6.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (64 commits)
r8152: add vendor/device ID pair for Microsoft Devkit
net: stmmac: add aux timestamps fifo clearance wait
bnxt: make sure we return pages to the pool
net: hns3: fix wrong use of rss size during VF rss config
ipv6: raw: Deduct extension header length in rawv6_push_pending_frames
net: lan966x: check for ptp to be enabled in lan966x_ptp_deinit()
net: sched: disallow noqueue for qdisc classes
iavf/iavf_main: actually log ->src mask when talking about it
igc: Fix PPS delta between two synchronized end-points
ixgbe: fix pci device refcount leak
octeontx2-pf: Fix resource leakage in VF driver unbind
selftests/net: l2_tos_ttl_inherit.sh: Ensure environment cleanup on failure.
selftests/net: l2_tos_ttl_inherit.sh: Run tests in their own netns.
selftests/net: l2_tos_ttl_inherit.sh: Set IPv6 addresses with "nodad".
net/mlx5e: Fix macsec possible null dereference when updating MAC security entity (SecY)
net/mlx5e: Fix macsec ssci attribute handling in offload path
net/mlx5: E-switch, Coverity: overlapping copy
net/mlx5e: Don't support encap rules with gbp option
net/mlx5: Fix ptp max frequency adjustment range
net/mlx5e: Fix memory leak on updating vport counters
...
Pull spi fixes from Mark Brown:
- Fixes for long standing issues with accesses to spidev->spi during
teardown in the spidev userspace driver.
- Rename the newly added spi-cs-setup-ns DT property to be more in line
with our other delay properties before it becomes ABI.
- A few driver specific fixes.
* tag 'spi-fix-v6.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
spi: spidev: remove debug messages that access spidev->spi without locking
spi: spidev: fix a race condition when accessing spidev->spi
spi: Rename spi-cs-setup-ns property to spi-cs-setup-delay-ns
spi: dt-bindings: Rename spi-cs-setup-ns to spi-cs-setup-delay-ns
spi: cadence: Fix busy cycles calculation
spi: mediatek: Enable irq before the spi registration
In commit 14243b3871 ("KVM: x86/xen: Add KVM_IRQ_ROUTING_XEN_EVTCHN
and event channel delivery") the clever version of me left some helpful
notes for those who would come after him:
/*
* For the irqfd workqueue, using the main kvm->lock mutex is
* fine since this function is invoked from kvm_set_irq() with
* no other lock held, no srcu. In future if it will be called
* directly from a vCPU thread (e.g. on hypercall for an IPI)
* then it may need to switch to using a leaf-node mutex for
* serializing the shared_info mapping.
*/
mutex_lock(&kvm->lock);
In commit 2fd6df2f2b ("KVM: x86/xen: intercept EVTCHNOP_send from guests")
the other version of me ran straight past that comment without reading it,
and introduced a potential deadlock by taking vcpu->mutex and kvm->lock
in the wrong order.
Solve this as originally suggested, by adding a leaf-node lock in the Xen
state rather than using kvm->lock for it.
Fixes: 2fd6df2f2b ("KVM: x86/xen: intercept EVTCHNOP_send from guests")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20230111180651.14394-4-dwmw2@infradead.org>
[Rebase, add docs. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM/arm64 fixes for 6.2, take #1
- Fix the PMCR_EL0 reset value after the PMU rework
- Correctly handle S2 fault triggered by a S1 page table walk
by not always classifying it as a write, as this breaks on
R/O memslots
- Document why we cannot exit with KVM_EXIT_MMIO when taking
a write fault from a S1 PTW on a R/O memslot
- Put the Apple M2 on the naughty step for not being able to
correctly implement the vgic SEIS feature, just liek the M1
before it
- Reviewer updates: Alex is stepping down, replaced by Zenghui
kvm->srcu is taken in KVM_RUN and several other vCPU ioctls, therefore
vcpu->mutex is susceptible to the same deadlock that is documented
for kvm->slots_lock. The same holds for kvm->lock, since kvm->lock
is held outside vcpu->mutex. Fix the documentation and rearrange it
to highlight the difference between these locks and kvm->slots_arch_lock,
and how kvm->slots_arch_lock can be useful while processing a vmexit.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull cpufreq ARM fixes for 6.2-rc4 from Viresh Kumar:
"- Fix double initialization and set suspend-freq for Apple's cpufreq
driver (Arnd Bergmann and Hector Martin).
- Fix reading of "reg" property, update cpufreq-dt's blocklist and
update DT documentation for Qualcomm's cpufreq driver (Konrad Dybcio
and Krzysztof Kozlowski).
- Replace 0 with NULL for Armada driver (Miles Chen).
- Fix potential overflows in CPPC driver (Pierre Gondois).
- Update blocklist for Tegra234 Soc (Sumit Gupta)."
