All known fields in ID_AA64ZFR0_EL1 describe the unprivileged
instructions supported by the PE's SVE implementation. Allow userspace
to pick and choose the advertised feature set, though nothing stops the
guest from using undisclosed instructions.
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-10-oliver.upton@linux.devSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

Allow userspace to change the guest-visible value of the register with
some severe limitation:

 - No changes to features not virtualized by KVM (AMU, MPAM, RAS)

 - Short of full GICv2 emulation in kernel, hiding GICv3 from the guest
   makes absolutely no sense.

 - FP is effectively assumed for KVM VMs.
Signed-off-by: Jing Zhang <jingzhangos@google.com>
[oliver: restrict features that are illogical to change]
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-9-oliver.upton@linux.devSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

Allow userspace to modify the guest-visible values of these ID
registers. Prevent changes to any of the virtualization features until
KVM picks up support for nested and we have a handle on managing NV
features.
Signed-off-by: Jing Zhang <jingzhangos@google.com>
[oliver: prevent changes to EL2 features for now]
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-8-oliver.upton@linux.devSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

Almost all of the features described by the ISA registers have no KVM
involvement. Allow userspace to change the value of these registers with
a couple exceptions:

 - MOPS is not writable as KVM does not currently virtualize FEAT_MOPS.

 - The PAuth fields are not writable as KVM requires both address and
   generic authentication be enabled.
Co-developed-by: Jing Zhang <jingzhangos@google.com>
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-7-oliver.upton@linux.devSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

Since ID_AA64DFR0_EL1 and ID_DFR0_EL1 are now writable from userspace,
it is safe to bump up the default KVM sanitised debug version to v8p8.
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-6-oliver.upton@linux.devSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

The debug architecture is mandatory in ARMv8, so KVM should not allow
userspace to configure a vCPU with less than that. Of course, this isn't
handled elegantly by the generic ID register plumbing, as the respective
ID register fields have a nonzero starting value.

Add an explicit check for debug versions less than v8 of the
architecture.
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-5-oliver.upton@linux.devSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

Much like we do for other fields, extract the Debug architecture version
from the ID register to populate the corresponding field in DBGDIDR.
Rewrite the existing sysreg field extractors to use SYS_FIELD_GET() for
consistency.
Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Since KVM now supports per-VM ID registers, use per-VM ID register
values for the sake of emulation for DBGDIDR and LORegion.
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-4-oliver.upton@linux.devSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

Add some basic documentation on how to get feature ID register writable
masks from userspace.
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-3-oliver.upton@linux.devSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

While the Feature ID range is well defined and pretty large, it isn't
inconceivable that the architecture will eventually grow some other
ranges that will need to similarly be described to userspace.

Add a VM ioctl to allow userspace to get writable masks for feature ID
registers in below system register space:
op0 = 3, op1 = {0, 1, 3}, CRn = 0, CRm = {0 - 7}, op2 = {0 - 7}
This is used to support mix-and-match userspace and kernels for writable
ID registers, where userspace may want to know upfront whether it can
actually tweak the contents of an idreg or not.

Add a new capability (KVM_CAP_ARM_SUPPORTED_FEATURE_ID_RANGES) that
returns a bitmap of the valid ranges, which can subsequently be
retrieved, one at a time by setting the index of the set bit as the
range identifier.
Suggested-by: Marc Zyngier <maz@kernel.org>
Suggested-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231003230408.3405722-2-oliver.upton@linux.devSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

Pull kvm fixes from Paolo Bonzini:
"ARM:

   - Fix EL2 Stage-1 MMIO mappings where a random address was used

   - Fix SMCCC function number comparison when the SVE hint is set

  RISC-V:

   - Fix KVM_GET_REG_LIST API for ISA_EXT registers

   - Fix reading ISA_EXT register of a missing extension

   - Fix ISA_EXT register handling in get-reg-list test

   - Fix filtering of AIA registers in get-reg-list test

  x86:

   - Fixes for TSC_AUX virtualization

   - Stop zapping page tables asynchronously, since we don't zap them as
     often as before"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: SVM: Do not use user return MSR support for virtualized TSC_AUX
  KVM: SVM: Fix TSC_AUX virtualization setup
  KVM: SVM: INTERCEPT_RDTSCP is never intercepted anyway
  KVM: x86/mmu: Stop zapping invalidated TDP MMU roots asynchronously
  KVM: x86/mmu: Do not filter address spaces in for_each_tdp_mmu_root_yield_safe()
  KVM: x86/mmu: Open code leaf invalidation from mmu_notifier
  KVM: riscv: selftests: Selectively filter-out AIA registers
  KVM: riscv: selftests: Fix ISA_EXT register handling in get-reg-list
  RISC-V: KVM: Fix riscv_vcpu_get_isa_ext_single() for missing extensions
  RISC-V: KVM: Fix KVM_GET_REG_LIST API for ISA_EXT registers
  KVM: selftests: Assert that vasprintf() is successful
  KVM: arm64: nvhe: Ignore SVE hint in SMCCC function ID
  KVM: arm64: Properly return allocated EL2 VA from hyp_alloc_private_va_range()

Pull tracing fixes from Steven Rostedt:

 - Fix the "bytes" output of the per_cpu stat file

   The tracefs/per_cpu/cpu*/stats "bytes" was giving bogus values as the
   accounting was not accurate. It is suppose to show how many used
   bytes are still in the ring buffer, but even when the ring buffer was
   empty it would still show there were bytes used.

 - Fix a bug in eventfs where reading a dynamic event directory (open)
   and then creating a dynamic event that goes into that diretory screws
   up the accounting.

   On close, the newly created event dentry will get a "dput" without
   ever having a "dget" done for it. The fix is to allocate an array on
   dir open to save what dentries were actually "dget" on, and what ones
   to "dput" on close.

* tag 'trace-v6.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  eventfs: Remember what dentries were created on dir open
  ring-buffer: Fix bytes info in per_cpu buffer stats

Pull cxl fixes from Dan Williams:
 "A collection of regression fixes, bug fixes, and some small cleanups
  to the Compute Express Link code.

  The regressions arrived in the v6.5 dev cycle and missed the v6.6
  merge window due to my personal absences this cycle. The most
  important fixes are for scenarios where the CXL subsystem fails to
  parse valid region configurations established by platform firmware.
  This is important because agreement between OS and BIOS on the CXL
  configuration is fundamental to implementing "OS native" error
  handling, i.e. address translation and component failure
  identification.

  Other important fixes are a driver load error when the BIOS lets the
  Linux PCI core handle AER events, but not CXL memory errors.

  The other fixex might have end user impact, but for now are only known
  to trigger in our test/emulation environment.

  Summary:

   - Fix multiple scenarios where platform firmware defined regions fail
     to be assembled by the CXL core.

   - Fix a spurious driver-load failure on platforms that enable OS
     native AER, but not OS native CXL error handling.

   - Fix a regression detecting "poison" commands when "security"
     commands are also defined.

   - Fix a cxl_test regression with the move to centralize CXL port
     register enumeration in the CXL core.

   - Miscellaneous small fixes and cleanups"

* tag 'cxl-fixes-6.6-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl:
  cxl/acpi: Annotate struct cxl_cxims_data with __counted_by
  cxl/port: Fix cxl_test register enumeration regression
  cxl/region: Refactor granularity select in cxl_port_setup_targets()
  cxl/region: Match auto-discovered region decoders by HPA range
  cxl/mbox: Fix CEL logic for poison and security commands
  cxl/pci: Replace host_bridge->native_aer with pcie_aer_is_native()
  PCI/AER: Export pcie_aer_is_native()
  cxl/pci: Fix appropriate checking for _OSC while handling CXL RAS registers

Pull gpio fixes from Bartosz Golaszewski:

 - fix an invalid usage of __free(kfree) leading to kfreeing an
   ERR_PTR()

 - fix an irq domain leak in gpio-tb10x

 - MAINTAINERS update

* tag 'gpio-fixes-for-v6.6-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
  gpio: sim: fix an invalid __free() usage
  gpio: tb10x: Fix an error handling path in tb10x_gpio_probe()
  MAINTAINERS: gpio-regmap: make myself a maintainer of it

Merge tag 'mm-hotfixes-stable-2023-09-23-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "13 hotfixes, 10 of which pertain to post-6.5 issues. The other three
  are cc:stable"

* tag 'mm-hotfixes-stable-2023-09-23-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  proc: nommu: fix empty /proc/<pid>/maps
  filemap: add filemap_map_order0_folio() to handle order0 folio
  proc: nommu: /proc/<pid>/maps: release mmap read lock
  mm: memcontrol: fix GFP_NOFS recursion in memory.high enforcement
  pidfd: prevent a kernel-doc warning
  argv_split: fix kernel-doc warnings
  scatterlist: add missing function params to kernel-doc
  selftests/proc: fixup proc-empty-vm test after KSM changes
  revert "scripts/gdb/symbols: add specific ko module load command"
  selftests: link libasan statically for tests with -fsanitize=address
  task_work: add kerneldoc annotation for 'data' argument
  mm: page_alloc: fix CMA and HIGHATOMIC landing on the wrong buddy list
  sh: mm: re-add lost __ref to ioremap_prot() to fix modpost warning

Pull smb client fixes from Steve French:
 "Six smb3 client fixes, including three for stable, from the SMB
  plugfest (testing event) this week:

   - Reparse point handling fix (found when investigating dir
     enumeration when fifo in dir)

   - Fix excessive thread creation for dir lease cleanup

   - UAF fix in negotiate path

   - remove duplicate error message mapping and fix confusing warning
     message

   - add dynamic trace point to improve debugging RDMA connection
     attempts"

* tag '6.6-rc2-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  smb3: fix confusing debug message
  smb: client: handle STATUS_IO_REPARSE_TAG_NOT_HANDLED
  smb3: remove duplicate error mapping
  cifs: Fix UAF in cifs_demultiplex_thread()
  smb3: do not start laundromat thread when dir leases  disabled
  smb3: Add dynamic trace points for RDMA (smbdirect) reconnect

Pull i2c fixes from Wolfram Sang:
 "A set of I2C driver fixes. Mostly fixing resource leaks or sanity
  checks"

* tag 'i2c-for-6.6-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: xiic: Correct return value check for xiic_reinit()
  i2c: mux: gpio: Add missing fwnode_handle_put()
  i2c: mux: demux-pinctrl: check the return value of devm_kstrdup()
  i2c: designware: fix __i2c_dw_disable() in case master is holding SCL low
  i2c: i801: unregister tco_pdev in i801_probe() error path

The code was accidentally mixing new and old style macros, update the
macros used to remove an unused function warning whilst building with
no PM enabled in the config.

Fixes: ace6d144 ("mfd: cs42l43: Add support for cs42l43 core driver")
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/all/20230822114914.340359-1-ckeepax@opensource.cirrus.com/Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Lee Jones <lee@kernel.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'loongarch-fixes-6.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch fixes from Huacai Chen:
 "Fix lockdep, fix a boot failure, fix some build warnings, fix document
  links, and some cleanups"

* tag 'loongarch-fixes-6.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
  docs/zh_CN/LoongArch: Update the links of ABI
  docs/LoongArch: Update the links of ABI
  LoongArch: Don't inline kasan_mem_to_shadow()/kasan_shadow_to_mem()
  kasan: Cleanup the __HAVE_ARCH_SHADOW_MAP usage
  LoongArch: Set all reserved memblocks on Node#0 at initialization
  LoongArch: Remove dead code in relocate_new_kernel
  LoongArch: Use _UL() and _ULL()
  LoongArch: Fix some build warnings with W=1
  LoongArch: Fix lockdep static memory detection

Pull s390 fixes from Vasily Gorbik:

 - Fix potential string buffer overflow in hypervisor user-defined
   certificates handling

 - Update defconfigs

* tag 's390-6.6-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/cert_store: fix string length handling
  s390: update defconfigs

Pull iomap fixes from Darrick Wong:

 - Return EIO on bad inputs to iomap_to_bh instead of BUGging, to deal
   less poorly with block device io racing with block device resizing

 - Fix a stale page data exposure bug introduced in 6.6-rc1 when
   unsharing a file range that is not in the page cache

* tag 'iomap-6.6-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  iomap: convert iomap_unshare_iter to use large folios
  iomap: don't skip reading in !uptodate folios when unsharing a range
  iomap: handle error conditions more gracefully in iomap_to_bh

KVM/riscv fixes for 6.6, take #1

- Fix KVM_GET_REG_LIST API for ISA_EXT registers
- Fix reading ISA_EXT register of a missing extension
- Fix ISA_EXT register handling in get-reg-list test
- Fix filtering of AIA registers in get-reg-list test

When the TSC_AUX MSR is virtualized, the TSC_AUX value is swap type "B"
within the VMSA. This means that the guest value is loaded on VMRUN and
the host value is restored from the host save area on #VMEXIT.

Since the value is restored on #VMEXIT, the KVM user return MSR support
for TSC_AUX can be replaced by populating the host save area with the
current host value of TSC_AUX. And, since TSC_AUX is not changed by Linux
post-boot, the host save area can be set once in svm_hardware_enable().
This eliminates the two WRMSR instructions associated with the user return
MSR support.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <d381de38eb0ab6c9c93dda8503b72b72546053d7.1694811272.git.thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The checks for virtualizing TSC_AUX occur during the vCPU reset processing
path. However, at the time of initial vCPU reset processing, when the vCPU
is first created, not all of the guest CPUID information has been set. In
this case the RDTSCP and RDPID feature support for the guest is not in
place and so TSC_AUX virtualization is not established.

This continues for each vCPU created for the guest. On the first boot of
an AP, vCPU reset processing is executed as a result of an APIC INIT
event, this time with all of the guest CPUID information set, resulting
in TSC_AUX virtualization being enabled, but only for the APs. The BSP
always sees a TSC_AUX value of 0 which probably went unnoticed because,
at least for Linux, the BSP TSC_AUX value is 0.

Move the TSC_AUX virtualization enablement out of the init_vmcb() path and
into the vcpu_after_set_cpuid() path to allow for proper initialization of
the support after the guest CPUID information has been set.

With the TSC_AUX virtualization support now in the vcpu_set_after_cpuid()
path, the intercepts must be either cleared or set based on the guest
CPUID input.

Fixes: 296d5a17 ("KVM: SEV-ES: Use V_TSC_AUX if available instead of RDTSC/MSR_TSC_AUX intercepts")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <4137fbcb9008951ab5f0befa74a0399d2cce809a.1694811272.git.thomas.lendacky@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

svm_recalc_instruction_intercepts() is always called at least once
before the vCPU is started, so the setting or clearing of the RDTSCP
intercept can be dropped from the TSC_AUX virtualization support.

Extracted from a patch by Tom Lendacky.

Cc: stable@vger.kernel.org
Fixes: 296d5a17 ("KVM: SEV-ES: Use V_TSC_AUX if available instead of RDTSC/MSR_TSC_AUX intercepts")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Stop zapping invalidate TDP MMU roots via work queue now that KVM
preserves TDP MMU roots until they are explicitly invalidated.  Zapping
roots asynchronously was effectively a workaround to avoid stalling a vCPU
for an extended during if a vCPU unloaded a root, which at the time
happened whenever the guest toggled CR0.WP (a frequent operation for some
guest kernels).

While a clever hack, zapping roots via an unbound worker had subtle,
unintended consequences on host scheduling, especially when zapping
multiple roots, e.g. as part of a memslot.  Because the work of zapping a
root is no longer bound to the task that initiated the zap, things like
the CPU affinity and priority of the original task get lost.  Losing the
affinity and priority can be especially problematic if unbound workqueues
aren't affined to a small number of CPUs, as zapping multiple roots can
cause KVM to heavily utilize the majority of CPUs in the system, *beyond*
the CPUs KVM is already using to run vCPUs.

When deleting a memslot via KVM_SET_USER_MEMORY_REGION, the async root
zap can result in KVM occupying all logical CPUs for ~8ms, and result in
high priority tasks not being scheduled in in a timely manner.  In v5.15,
which doesn't preserve unloaded roots, the issues were even more noticeable
as KVM would zap roots more frequently and could occupy all CPUs for 50ms+.

Consuming all CPUs for an extended duration can lead to significant jitter
throughout the system, e.g. on ChromeOS with virtio-gpu, deleting memslots
is a semi-frequent operation as memslots are deleted and recreated with
different host virtual addresses to react to host GPU drivers allocating
and freeing GPU blobs.  On ChromeOS, the jitter manifests as audio blips
during games due to the audio server's tasks not getting scheduled in
promptly, despite the tasks having a high realtime priority.

Deleting memslots isn't exactly a fast path and should be avoided when
possible, and ChromeOS is working towards utilizing MAP_FIXED to avoid the
memslot shenanigans, but KVM is squarely in the wrong.  Not to mention
that removing the async zapping eliminates a non-trivial amount of
complexity.

Note, one of the subtle behaviors hidden behind the async zapping is that
KVM would zap invalidated roots only once (ignoring partial zaps from
things like mmu_notifier events).  Preserve this behavior by adding a flag
to identify roots that are scheduled to be zapped versus roots that have
already been zapped but not yet freed.

Add a comment calling out why kvm_tdp_mmu_invalidate_all_roots() can
encounter invalid roots, as it's not at all obvious why zapping
invalidated roots shouldn't simply zap all invalid roots.
Reported-by: Pattara Teerapong <pteerapong@google.com>
Cc: David Stevens <stevensd@google.com>
Cc: Yiwei Zhang<zzyiwei@google.com>
Cc: Paul Hsia <paulhsia@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230916003916.2545000-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

All callers except the MMU notifier want to process all address spaces.
Remove the address space ID argument of for_each_tdp_mmu_root_yield_safe()
and switch the MMU notifier to use __for_each_tdp_mmu_root_yield_safe().

Extracted out of a patch by Sean Christopherson <seanjc@google.com>

Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Pull hardening fixes from Kees Cook:

 - Fix UAPI stddef.h to avoid C++-ism (Alexey Dobriyan)

 - Fix harmless UAPI stddef.h header guard endif (Alexey Dobriyan)

* tag 'hardening-v6.6-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  uapi: stddef.h: Fix __DECLARE_FLEX_ARRAY for C++
  uapi: stddef.h: Fix header guard location

Pull xfs fixes from Chandan Babu:

 - Fix an integer overflow bug when processing an fsmap call

 - Fix crash due to CPU hot remove event racing with filesystem mount
   operation

 - During read-only mount, XFS does not allow the contents of the log to
   be recovered when there are one or more unrecognized rcompat features
   in the primary superblock, since the log might have intent items
   which the kernel does not know how to process

 - During recovery of log intent items, XFS now reserves log space
   sufficient for one cycle of a permanent transaction to execute.
   Otherwise, this could lead to livelocks due to non-availability of
   log space

 - On an fs which has an ondisk unlinked inode list, trying to delete a
   file or allocating an O_TMPFILE file can cause the fs to the shutdown
   if the first inode in the ondisk inode list is not present in the
   inode cache. The bug is solved by explicitly loading the first inode
   in the ondisk unlinked inode list into the inode cache if it is not
   already cached

   A similar problem arises when the uncached inode is present in the
   middle of the ondisk unlinked inode list. This second bug is
   triggered when executing operations like quotacheck and bulkstat. In
   this case, XFS now reads in the entire ondisk unlinked inode list

 - Enable LARP mode only on recent v5 filesystems

 - Fix a out of bounds memory access in scrub

 - Fix a performance bug when locating the tail of the log during
   mounting a filesystem

* tag 'xfs-6.6-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: use roundup_pow_of_two instead of ffs during xlog_find_tail
  xfs: only call xchk_stats_merge after validating scrub inputs
  xfs: require a relatively recent V5 filesystem for LARP mode
  xfs: make inode unlinked bucket recovery work with quotacheck
  xfs: load uncached unlinked inodes into memory on demand
  xfs: reserve less log space when recovering log intent items
  xfs: fix log recovery when unknown rocompat bits are set
  xfs: reload entire unlinked bucket lists
  xfs: allow inode inactivation during a ro mount log recovery
  xfs: use i_prev_unlinked to distinguish inodes that are not on the unlinked list
  xfs: remove CPU hotplug infrastructure
  xfs: remove the all-mounts list
  xfs: use per-mount cpumask to track nonempty percpu inodegc lists
  xfs: fix an agbno overflow in __xfs_getfsmap_datadev
  xfs: fix per-cpu CIL structure aggregation racing with dying cpus
  xfs: fix select in config XFS_ONLINE_SCRUB_STATS

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct cxl_cxims_data.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Alison Schofield <alison.schofield@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: linux-cxl@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20230922175319.work.096-kees@kernel.orgSigned-off-by: Dan Williams <dan.j.williams@intel.com>

The cxl_test unit test environment models a CXL topology for
sysfs/user-ABI regression testing. It uses interface mocking via the
"--wrap=" linker option to redirect cxl_core routines that parse
hardware registers with versions that just publish objects, like
devm_cxl_enumerate_decoders().

Starting with:

Commit 19ab69a6 ("cxl/port: Store the port's Component Register mappings in struct cxl_port")

...port register enumeration is moved into devm_cxl_add_port(). This
conflicts with the "cxl_test avoids emulating registers stance" so
either the port code needs to be refactored (too violent), or modified
so that register enumeration is skipped on "fake" cxl_test ports
(annoying, but straightforward).

This conflict has happened previously and the "check for platform
device" workaround to avoid instrusive refactoring was deployed in those
scenarios. In general, refactoring should only benefit production code,
test code needs to remain minimally instrusive to the greatest extent
possible.

This was missed previously because it may sometimes just cause warning
messages to be emitted, but it can also cause test failures. The
backport to -stable is only nice to have for clean cxl_test runs.

Fixes: 19ab69a6 ("cxl/port: Store the port's Component Register mappings in struct cxl_port")
Cc: stable@vger.kernel.org
Reported-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Tested-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/169476525052.1013896.6235102957693675187.stgit@dwillia2-xfh.jf.intel.comSigned-off-by: Dan Williams <dan.j.williams@intel.com>

Using the following code with libtracefs:

	int dfd;

	// create the directory events/kprobes/kp1
	tracefs_kprobe_raw(NULL, "kp1", "schedule_timeout", "time=$arg1");

	// Open the kprobes directory
	dfd = tracefs_instance_file_open(NULL, "events/kprobes", O_RDONLY);

	// Do a lookup of the kprobes/kp1 directory (by looking at enable)
	tracefs_file_exists(NULL, "events/kprobes/kp1/enable");

	// Now create a new entry in the kprobes directory
	tracefs_kprobe_raw(NULL, "kp2", "schedule_hrtimeout", "expires=$arg1");

	// Do another lookup to create the dentries
	tracefs_file_exists(NULL, "events/kprobes/kp2/enable"))

	// Close the directory
	close(dfd);

What happened above, the first open (dfd) will call
dcache_dir_open_wrapper() that will create the dentries and up their ref
counts.

Now the creation of "kp2" will add another dentry within the kprobes
directory.

Upon the close of dfd, eventfs_release() will now do a dput for all the
entries in kprobes. But this is where the problem lies. The open only
upped the dentry of kp1 and not kp2. Now the close is decrementing both
kp1 and kp2, which causes kp2 to get a negative count.

Doing a "trace-cmd reset" which deletes all the kprobes cause the kernel
to crash! (due to the messed up accounting of the ref counts).

To solve this, save all the dentries that are opened in the
dcache_dir_open_wrapper() into an array, and use this array to know what
dentries to do a dput on in eventfs_release().

Since the dcache_dir_open_wrapper() calls dcache_dir_open() which uses the
file->private_data, we need to also add a wrapper around dcache_readdir()
that uses the cursor assigned to the file->private_data. This is because
the dentries need to also be saved in the file->private_data. To do this
create the structure:

  struct dentry_list {
	void		*cursor;
	struct dentry	**dentries;
  };

Which will hold both the cursor and the dentries. Some shuffling around is
needed to make sure that dcache_dir_open() and dcache_readdir() only see
the cursor.

Link: https://lore.kernel.org/linux-trace-kernel/20230919211804.230edf1e@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20230922163446.1431d4fa@gandalf.local.home

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ajay Kaher <akaher@vmware.com>
Fixes: 63940449 ("eventfs: Implement eventfs lookup, read, open functions")
Reported-by: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

The 'bytes' info in file 'per_cpu/cpu<X>/stats' means the number of
bytes in cpu buffer that have not been consumed. However, currently
after consuming data by reading file 'trace_pipe', the 'bytes' info
was not changed as expected.

  # cat per_cpu/cpu0/stats
  entries: 0
  overrun: 0
  commit overrun: 0
  bytes: 568             <--- 'bytes' is problematical !!!
  oldest event ts:  8651.371479
  now ts:  8653.912224
  dropped events: 0
  read events: 8

The root cause is incorrect stat on cpu_buffer->read_bytes. To fix it:
  1. When stat 'read_bytes', account consumed event in rb_advance_reader();
  2. When stat 'entries_bytes', exclude the discarded padding event which
     is smaller than minimum size because it is invisible to reader. Then
     use rb_page_commit() instead of BUF_PAGE_SIZE at where accounting for
     page-based read/remove/overrun.

Also correct the comments of ring_buffer_bytes_cpu() in this patch.

Link: https://lore.kernel.org/linux-trace-kernel/20230921125425.1708423-1-zhengyejian1@huawei.com

Cc: stable@vger.kernel.org
Fixes: c64e148a ("trace: Add ring buffer stats to measure rate of events")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Pull thermal control fix from Rafael Wysocki:
 "Unbreak the trip point update sysfs interface that has been broken
  since the 6.3 cycle (Rafael Wysocki)"

* tag 'thermal-6.6-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  thermal: sysfs: Fix trip_point_hyst_store()

Pull ACPI fixes from Rafael Wysocki:
 "These fix a general ACPI processor driver regression and an ia64 build
  issue, both introduced recently.

  Specifics:

   - Fix recently introduced uninitialized memory access issue in the
     ACPI processor driver (Michal Wilczynski)

   - Fix ia64 build inadvertently broken by recent ACPI processor driver
     changes, which is prudent to do for 6.6 even though ia64 support is
     slated for removal in 6.7 (Ard Biesheuvel)"

* tag 'acpi-6.6-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: processor: Fix uninitialized access of buf in acpi_set_pdc_bits()
  acpi: Provide ia64 dummy implementation of acpi_proc_quirk_mwait_check()

Pull arm64 fixes from Will Deacon:
 "Small crop of relatively boring arm64 fixes for -rc3.

  That's not to say we don't have any juicy bugs, however, it's just
  that fixes for those are likely to come via -mm and -tip for a hugetlb
  and an atomics issue respectively. I get left with the
  documentation...

   - Fix detection of "ClearBHB" and "Hinted Conditional Branch" features

   - Fix broken wildcarding for Arm PMU MAINTAINERS entry

   - Add missing documentation for userspace-visible ID register fields"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Document missing userspace visible fields in ID_AA64ISAR2_EL1
  arm64/hbc: Document HWCAP2_HBC
  arm64/sme: Include ID_AA64PFR1_EL1.SME in cpu-feature-registers.rst
  arm64: cpufeature: Fix CLRBHB and BC detection
  MAINTAINERS: Use wildcard pattern for ARM PMU headers

Pull x86 rethunk fixes from Borislav Petkov:
 "Fix the patching ordering between static calls and return thunks"

* tag 'x86_urgent_for_v6.6-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86,static_call: Fix static-call vs return-thunk
  x86/alternatives: Remove faulty optimization

Pull misc x86 fixes from Ingo Molnar:

 - Fix a kexec bug

 - Fix an UML build bug

 - Fix a handful of SRSO related bugs

 - Fix a shadow stacks handling bug & robustify related code

* tag 'x86-urgent-2023-09-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/shstk: Add warning for shadow stack double unmap
  x86/shstk: Remove useless clone error handling
  x86/shstk: Handle vfork clone failure correctly
  x86/srso: Fix SBPB enablement for spec_rstack_overflow=off
  x86/srso: Don't probe microcode in a guest
  x86/srso: Set CPUID feature bits independently of bug or mitigation status
  x86/srso: Fix srso_show_state() side effect
  x86/asm: Fix build of UML with KASAN
  x86/mm, kexec, ima: Use memblock_free_late() from ima_free_kexec_buffer()

Pull scheduler fix from Ingo Molnar:
 "Fix a PF_IDLE initialization bug that generated warnings on tiny-RCU"

* tag 'sched-urgent-2023-09-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kernel/sched: Modify initial boot task idle setup