The hypervisor returns migration failure if all VAS windows are not
closed. During pre-migration stage, vas_migration_handler() sets
migration_in_progress flag and closes all windows from the list.
The allocate VAS window routine checks the migration flag, setup
the window and then add it to the list. So there is possibility of
the migration handler missing the window that is still in the
process of setup.

t1: Allocate and open VAS	t2: Migration event
    window

lock vas_pseries_mutex
If migration_in_progress set
  unlock vas_pseries_mutex
  return
open window HCALL
unlock vas_pseries_mutex
Modify window HCALL		lock vas_pseries_mutex
setup window			migration_in_progress=true
				Closes all windows from the list
				// May miss windows that are
				// not in the list
				unlock vas_pseries_mutex
lock vas_pseries_mutex		return
if nr_closed_windows == 0
  // No DLPAR CPU or migration
  add window to the list
  // Window will be added to the
  // list after the setup is completed
  unlock vas_pseries_mutex
  return
unlock vas_pseries_mutex
Close VAS window
// due to DLPAR CPU or migration
return -EBUSY

This patch resolves the issue with the following steps:
- Set the migration_in_progress flag without holding mutex.
- Introduce nr_open_wins_progress counter in VAS capabilities
  struct
- This counter tracks the number of open windows are still in
  progress
- The allocate setup window thread closes windows if the migration
  is set and decrements nr_open_window_progress counter
- The migration handler waits for no in-progress open windows.

The code flow with the fix is as follows:

t1: Allocate and open VAS       t2: Migration event
    window

lock vas_pseries_mutex
If migration_in_progress set
   unlock vas_pseries_mutex
   return
open window HCALL
nr_open_wins_progress++
// Window opened, but not
// added to the list yet
unlock vas_pseries_mutex
Modify window HCALL		migration_in_progress=true
setup window			lock vas_pseries_mutex
				Closes all windows from the list
				While nr_open_wins_progress {
				    unlock vas_pseries_mutex
lock vas_pseries_mutex		    sleep
if nr_closed_windows == 0	    // Wait if any open window in
or migration is not started	    // progress. The open window
   // No DLPAR CPU or migration	    // thread closes the window without
   add window to the list	    // adding to the list and return if
   nr_open_wins_progress--	    // the migration is in progress.
   unlock vas_pseries_mutex
   return
Close VAS window
nr_open_wins_progress--
unlock vas_pseries_mutex
return -EBUSY			    lock vas_pseries_mutex
				}
				unlock vas_pseries_mutex
				return

Fixes: 37e6764895ef ("powerpc/pseries/vas: Add VAS migration handler")
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231125235104.3405008-1-haren@linux.ibm.com

>From a W=1 build:

>> arch/powerpc/platforms/pseries/rtas-work-area.c:189: warning: Function parameter or member 'limit' not
>> described in 'rtas_work_area_reserve_arena'

Add the missing description of the limit parameter.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202309131221.Bm1pg96n-lkp@intel.com/
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231106-rtas-trivial-v1-1-61847655c51f@linux.ibm.com

Pull powerpc updates from Michael Ellerman:

 - Add support for KVM running as a nested hypervisor under development
   versions of PowerVM, using the new PAPR nested virtualisation API

 - Add support for the BPF prog pack allocator

 - A rework of the non-server MMU handling to support execute-only on
   all platforms

 - Some optimisations & cleanups for the powerpc qspinlock code

 - Various other small features and fixes

Thanks to Aboorva Devarajan, Aditya Gupta, Amit Machhiwal, Benjamin
Gray, Christophe Leroy, Dr. David Alan Gilbert, Gaurav Batra, Gautam
Menghani, Geert Uytterhoeven, Haren Myneni, Hari Bathini, Joel Stanley,
Jordan Niethe, Julia Lawall, Kautuk Consul, Kuan-Wei Chiu, Michael
Neuling, Minjie Du, Muhammad Muzammil, Naveen N Rao, Nicholas Piggin,
Nick Child, Nysal Jan K.A, Peter Lafreniere, Rob Herring, Sachin Sant,
Sebastian Andrzej Siewior, Shrikanth Hegde, Srikar Dronamraju, Stanislav
Kinsburskii, Vaibhav Jain, Wang Yufen, Yang Yingliang, and Yuan Tan.

* tag 'powerpc-6.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (100 commits)
  powerpc/vmcore: Add MMU information to vmcoreinfo
  Revert "powerpc: add `cur_cpu_spec` symbol to vmcoreinfo"
  powerpc/bpf: use bpf_jit_binary_pack_[alloc|finalize|free]
  powerpc/bpf: rename powerpc64_jit_data to powerpc_jit_data
  powerpc/bpf: implement bpf_arch_text_invalidate for bpf_prog_pack
  powerpc/bpf: implement bpf_arch_text_copy
  powerpc/code-patching: introduce patch_instructions()
  powerpc/32s: Implement local_flush_tlb_page_psize()
  powerpc/pseries: use kfree_sensitive() in plpks_gen_password()
  powerpc/code-patching: Perform hwsync in __patch_instruction() in case of failure
  powerpc/fsl_msi: Use device_get_match_data()
  powerpc: Remove cpm_dp...() macros
  powerpc/qspinlock: Rename yield_propagate_owner tunable
  powerpc/qspinlock: Propagate sleepy if previous waiter is preempted
  powerpc/qspinlock: don't propagate the not-sleepy state
  powerpc/qspinlock: propagate owner preemptedness rather than CPU number
  powerpc/qspinlock: stop queued waiters trying to set lock sleepy
  powerpc/perf: Fix disabling BHRB and instruction sampling
  powerpc/trace: Add support for HAVE_FUNCTION_ARG_ACCESS_API
  powerpc/tools: Pass -mabi=elfv2 to gcc-check-mprofile-kernel.sh
  ...

Pull sysctl updates from Luis Chamberlain:
 "To help make the move of sysctls out of kernel/sysctl.c not incur a
  size penalty sysctl has been changed to allow us to not require the
  sentinel, the final empty element on the sysctl array. Joel Granados
  has been doing all this work. On the v6.6 kernel we got the major
  infrastructure changes required to support this. For v6.7-rc1 we have
  all arch/ and drivers/ modified to remove the sentinel. Both arch and
  driver changes have been on linux-next for a bit less than a month. It
  is worth re-iterating the value:

   - this helps reduce the overall build time size of the kernel and run
     time memory consumed by the kernel by about ~64 bytes per array

   - the extra 64-byte penalty is no longer inncurred now when we move
     sysctls out from kernel/sysctl.c to their own files

  For v6.8-rc1 expect removal of all the sentinels and also then the
  unneeded check for procname == NULL.

  The last two patches are fixes recently merged by Krister Johansen
  which allow us again to use softlockup_panic early on boot. This used
  to work but the alias work broke it. This is useful for folks who want
  to detect softlockups super early rather than wait and spend money on
  cloud solutions with nothing but an eventual hung kernel. Although
  this hadn't gone through linux-next it's also a stable fix, so we
  might as well roll through the fixes now"

* tag 'sysctl-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (23 commits)
  watchdog: move softlockup_panic back to early_param
  proc: sysctl: prevent aliased sysctls from getting passed to init
  intel drm: Remove now superfluous sentinel element from ctl_table array
  Drivers: hv: Remove now superfluous sentinel element from ctl_table array
  raid: Remove now superfluous sentinel element from ctl_table array
  fw loader: Remove the now superfluous sentinel element from ctl_table array
  sgi-xp: Remove the now superfluous sentinel element from ctl_table array
  vrf: Remove the now superfluous sentinel element from ctl_table array
  char-misc: Remove the now superfluous sentinel element from ctl_table array
  infiniband: Remove the now superfluous sentinel element from ctl_table array
  macintosh: Remove the now superfluous sentinel element from ctl_table array
  parport: Remove the now superfluous sentinel element from ctl_table array
  scsi: Remove now superfluous sentinel element from ctl_table array
  tty: Remove now superfluous sentinel element from ctl_table array
  xen: Remove now superfluous sentinel element from ctl_table array
  hpet: Remove now superfluous sentinel element from ctl_table array
  c-sky: Remove now superfluous sentinel element from ctl_talbe array
  powerpc: Remove now superfluous sentinel element from ctl_table arrays
  riscv: Remove now superfluous sentinel element from ctl_table array
  x86/vdso: Remove now superfluous sentinel element from ctl_table array
  ...

Pull block updates from Jens Axboe:

 - Improvements to the queue_rqs() support, and adding null_blk support
   for that as well (Chengming)

 - Series improving badblocks support (Coly)

 - Key store support for sed-opal (Greg)

 - IBM partition string handling improvements (Jan)

 - Make number of ublk devices supported configurable (Mike)

 - Cancelation improvements for ublk (Ming)

 - MD pull requests via Song:
     - Handle timeout in md-cluster, by Denis Plotnikov
     - Cleanup pers->prepare_suspend, by Yu Kuai
     - Rewrite mddev_suspend(), by Yu Kuai
     - Simplify md_seq_ops, by Yu Kuai
     - Reduce unnecessary locking array_state_store(), by Mariusz
       Tkaczyk
     - Make rdev add/remove independent from daemon thread, by Yu Kuai
     - Refactor code around quiesce() and mddev_suspend(), by Yu Kuai

 - NVMe pull request via Keith:
     - nvme-auth updates (Mark)
     - nvme-tcp tls (Hannes)
     - nvme-fc annotaions (Kees)

 - Misc cleanups and improvements (Jiapeng, Joel)

* tag 'for-6.7/block-2023-10-30' of git://git.kernel.dk/linux: (95 commits)
  block: ublk_drv: Remove unused function
  md: cleanup pers->prepare_suspend()
  nvme-auth: allow mixing of secret and hash lengths
  nvme-auth: use transformed key size to create resp
  nvme-auth: alloc nvme_dhchap_key as single buffer
  nvmet-tcp: use 'spin_lock_bh' for state_lock()
  powerpc/pseries: PLPKS SED Opal keystore support
  block: sed-opal: keystore access for SED Opal keys
  block:sed-opal: SED Opal keystore
  ublk: simplify aborting request
  ublk: replace monitor with cancelable uring_cmd
  ublk: quiesce request queue when aborting queue
  ublk: rename mm_lock as lock
  ublk: move ublk_cancel_dev() out of ub->mutex
  ublk: make sure io cmd handled in submitter task context
  ublk: don't get ublk device reference in ublk_abort_queue()
  ublk: Make ublks_max configurable
  ublk: Limit dev_id/ub_number values
  md-cluster: check for timeout while a new disk adding
  nvme: rework NVME_AUTH Kconfig selection
  ...

Pull vfs inode time accessor updates from Christian Brauner:
 "This finishes the conversion of all inode time fields to accessor
  functions as discussed on list. Changing timestamps manually as we
  used to do before is error prone. Using accessors function makes this
  robust.

  It does not contain the switch of the time fields to discrete 64 bit
  integers to replace struct timespec and free up space in struct inode.
  But after this, the switch can be trivially made and the patch should
  only affect the vfs if we decide to do it"

* tag 'vfs-6.7.ctime' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (86 commits)
  fs: rename inode i_atime and i_mtime fields
  security: convert to new timestamp accessors
  selinux: convert to new timestamp accessors
  apparmor: convert to new timestamp accessors
  sunrpc: convert to new timestamp accessors
  mm: convert to new timestamp accessors
  bpf: convert to new timestamp accessors
  ipc: convert to new timestamp accessors
  linux: convert to new timestamp accessors
  zonefs: convert to new timestamp accessors
  xfs: convert to new timestamp accessors
  vboxsf: convert to new timestamp accessors
  ufs: convert to new timestamp accessors
  udf: convert to new timestamp accessors
  ubifs: convert to new timestamp accessors
  tracefs: convert to new timestamp accessors
  sysv: convert to new timestamp accessors
  squashfs: convert to new timestamp accessors
  server: convert to new timestamp accessors
  client: convert to new timestamp accessors
  ...

Pull misc vfs updates from Christian Brauner:
 "This contains the usual miscellaneous features, cleanups, and fixes
  for vfs and individual fses.

  Features:

   - Rename and export helpers that get write access to a mount. They
     are used in overlayfs to get write access to the upper mount.

   - Print the pretty name of the root device on boot failure. This
     helps in scenarios where we would usually only print
     "unknown-block(1,2)".

   - Add an internal SB_I_NOUMASK flag. This is another part in the
     endless POSIX ACL saga in a way.

     When POSIX ACLs are enabled via SB_POSIXACL the vfs cannot strip
     the umask because if the relevant inode has POSIX ACLs set it might
     take the umask from there. But if the inode doesn't have any POSIX
     ACLs set then we apply the umask in the filesytem itself. So we end
     up with:

      (1) no SB_POSIXACL -> strip umask in vfs
      (2) SB_POSIXACL    -> strip umask in filesystem

     The umask semantics associated with SB_POSIXACL allowed filesystems
     that don't even support POSIX ACLs at all to raise SB_POSIXACL
     purely to avoid umask stripping. That specifically means NFS v4 and
     Overlayfs. NFS v4 does it because it delegates this to the server
     and Overlayfs because it needs to delegate umask stripping to the
     upper filesystem, i.e., the filesystem used as the writable layer.

     This went so far that SB_POSIXACL is raised eve on kernels that
     don't even have POSIX ACL support at all.

     Stop this blatant abuse and add SB_I_NOUMASK which is an internal
     superblock flag that filesystems can raise to opt out of umask
     handling. That should really only be the two mentioned above. It's
     not that we want any filesystems to do this. Ideally we have all
     umask handling always in the vfs.

   - Make overlayfs use SB_I_NOUMASK too.

   - Now that we have SB_I_NOUMASK, stop checking for SB_POSIXACL in
     IS_POSIXACL() if the kernel doesn't have support for it. This is a
     very old patch but it's only possible to do this now with the wider
     cleanup that was done.

   - Follow-up work on fake path handling from last cycle. Citing mostly
     from Amir:

     When overlayfs was first merged, overlayfs files of regular files
     and directories, the ones that are installed in file table, had a
     "fake" path, namely, f_path is the overlayfs path and f_inode is
     the "real" inode on the underlying filesystem.

     In v6.5, we took another small step by introducing of the
     backing_file container and the file_real_path() helper. This change
     allowed vfs and filesystem code to get the "real" path of an
     overlayfs backing file. With this change, we were able to make
     fsnotify work correctly and report events on the "real" filesystem
     objects that were accessed via overlayfs.

     This method works fine, but it still leaves the vfs vulnerable to
     new code that is not aware of files with fake path. A recent
     example is commit db1d1e8b9867 ("IMA: use vfs_getattr_nosec to get
     the i_version"). This commit uses direct referencing to f_path in
     IMA code that otherwise uses file_inode() and file_dentry() to
     reference the filesystem objects that it is measuring.

     This contains work to switch things around: instead of having
     filesystem code opt-in to get the "real" path, have generic code
     opt-in for the "fake" path in the few places that it is needed.

     Is it far more likely that new filesystems code that does not use
     the file_dentry() and file_real_path() helpers will end up causing
     crashes or averting LSM/audit rules if we keep the "fake" path
     exposed by default.

     This change already makes file_dentry() moot, but for now we did
     not change this helper just added a WARN_ON() in ovl_d_real() to
     catch if we have made any wrong assumptions.

     After the dust settles on this change, we can make file_dentry() a
     plain accessor and we can drop the inode argument to ->d_real().

   - Switch struct file to SLAB_TYPESAFE_BY_RCU. This looks like a small
     change but it really isn't and I would like to see everyone on
     their tippie toes for any possible bugs from this work.

     Essentially we've been doing most of what SLAB_TYPESAFE_BY_RCU for
     files since a very long time because of the nasty interactions
     between the SCM_RIGHTS file descriptor garbage collection. So
     extending it makes a lot of sense but it is a subtle change. There
     are almost no places that fiddle with file rcu semantics directly
     and the ones that did mess around with struct file internal under
     rcu have been made to stop doing that because it really was always
     dodgy.

     I forgot to put in the link tag for this change and the discussion
     in the commit so adding it into the merge message:

       https://lore.kernel.org/r/20230926162228.68666-1-mjguzik@gmail.com

  Cleanups:

   - Various smaller pipe cleanups including the removal of a spin lock
     that was only used to protect against writes without pipe_lock()
     from O_NOTIFICATION_PIPE aka watch queues. As that was never
     implemented remove the additional locking from pipe_write().

   - Annotate struct watch_filter with the new __counted_by attribute.

   - Clarify do_unlinkat() cleanup so that it doesn't look like an extra
     iput() is done that would cause issues.

   - Simplify file cleanup when the file has never been opened.

   - Use module helper instead of open-coding it.

   - Predict error unlikely for stale retry.

   - Use WRITE_ONCE() for mount expiry field instead of just commenting
     that one hopes the compiler doesn't get smart.

  Fixes:

   - Fix readahead on block devices.

   - Fix writeback when layztime is enabled and inodes whose timestamp
     is the only thing that changed reside on wb->b_dirty_time. This
     caused excessively large zombie memory cgroup when lazytime was
     enabled as such inodes weren't handled fast enough.

   - Convert BUG_ON() to WARN_ON_ONCE() in open_last_lookups()"

* tag 'vfs-6.7.misc' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (26 commits)
  file, i915: fix file reference for mmap_singleton()
  vfs: Convert BUG_ON to WARN_ON_ONCE in open_last_lookups
  writeback, cgroup: switch inodes with dirty timestamps to release dying cgwbs
  chardev: Simplify usage of try_module_get()
  ovl: rely on SB_I_NOUMASK
  fs: fix umask on NFS with CONFIG_FS_POSIX_ACL=n
  fs: store real path instead of fake path in backing file f_path
  fs: create helper file_user_path() for user displayed mapped file path
  fs: get mnt_writers count for an open backing file's real path
  vfs: stop counting on gcc not messing with mnt_expiry_mark if not asked
  vfs: predict the error in retry_estale as unlikely
  backing file: free directly
  vfs: fix readahead(2) on block devices
  io_uring: use files_lookup_fd_locked()
  file: convert to SLAB_TYPESAFE_BY_RCU
  vfs: shave work on failed file open
  fs: simplify misleading code to remove ambiguity regarding ihold()/iput()
  watch_queue: Annotate struct watch_filter with __counted_by
  fs/pipe: use spinlock in pipe_read() only if there is a watch_queue
  fs/pipe: remove unnecessary spinlock from pipe_write()
  ...

password might contain private information, so better use
kfree_sensitive to free it.
In plpks_gen_password() use kfree_sensitive().

Signed-off-by: Minjie Du <duminjie@vivo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230717092648.9752-1-duminjie@vivo.com

If the vcpu_associativity alloc memory successfully but the
pcpu_associativity fails to alloc memory, the vcpu_associativity
memory leaks.

Fixes: d62c8deeb6e6 ("powerpc/pseries: Provide vcpu dispatch statistics")
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
Reviewed-by: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/1671003983-10794-1-git-send-email-wangyufen@huawei.com

The VAS open window call prints error message and returns -EBUSY
after the migration suspend event initiated and until the resume
event completed on the destination system. It can cause the log
buffer filled with these error messages if the user space issues
continuous open window calls.  Similar case even for DLPAR CPU
remove event when no credits are available until the credits are
freed or with the other DLPAR CPU add event.

So changes in the patch to use pr_err_ratelimited() instead of
pr_err() to display open window failure and not-available credits
error messages.

Use pr_fmt() and make the corresponding changes to have the
consistencein prefix all pr_*() messages (vas-api.c).

Fixes: 37e6764895ef ("powerpc/pseries/vas: Add VAS migration handler")
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
[mpe: Use "vas-api" as the prefix to match the file name.]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231019215033.1335251-1-haren@linux.ibm.com