Add fn and fn_arg members into struct kernel_clone_args and test for
them in copy_thread (instead of testing for PF_KTHREAD | PF_IO_WORKER).
This allows any task that wants to be a user space task that only runs
in kernel mode to use this functionality.

The code on x86 is an exception and still retains a PF_KTHREAD test
because x86 unlikely everything else handles kthreads slightly
differently than user space tasks that start with a function.

The functions that created tasks that start with a function
have been updated to set ".fn" and ".fn_arg" instead of
".stack" and ".stack_size".  These functions are fork_idle(),
create_io_thread(), kernel_thread(), and user_mode_thread().

Link: https://lkml.kernel.org/r/20220506141512.516114-4-ebiederm@xmission.comSigned-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

The architectures ia64 and parisc have special handling for the idle
thread in copy_process.  Add a flag named idle to kernel_clone_args
and use it to explicity test if an idle process is being created.

Fullfill the expectations of the rest of the copy_thread
implemetations and pass a function pointer in .stack from fork_idle().
This makes what is happening in copy_thread better defined, and is
useful to make idle threads less special.

Link: https://lkml.kernel.org/r/20220506141512.516114-3-ebiederm@xmission.comSigned-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

With io_uring we have started supporting tasks that are for most
purposes user space tasks that exclusively run code in kernel mode.

The kernel task that exec's init and tasks that exec user mode
helpers are also user mode tasks that just run kernel code
until they call kernel execve.

Pass kernel_clone_args into copy_thread so these oddball
tasks can be supported more cleanly and easily.

v2: Fix spelling of kenrel_clone_args on h8300
Link: https://lkml.kernel.org/r/20220506141512.516114-2-ebiederm@xmission.comSigned-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

If kthread_is_per_cpu runs concurrently with free_kthread_struct the
kthread_struct that was just freed may be read from.

This bug was introduced by commit 40966e31 ("kthread: Ensure
struct kthread is present for all kthreads").  When kthread_struct
started to be allocated for all tasks that have PF_KTHREAD set.  This
in turn required the kthread_struct to be freed in kernel_execve and
violated the assumption that kthread_struct will have the same
lifetime as the task.

Looking a bit deeper this only applies to callers of kernel_execve
which is just the init process and the user mode helper processes.
These processes really don't want to be kernel threads but are for
historical reasons.  Mostly that copy_thread does not know how to take
a kernel mode function to the process with for processes without
PF_KTHREAD or PF_IO_WORKER set.

Solve this by not allocating kthread_struct for the init process and
the user mode helper processes.

This is done by adding a kthread member to struct kernel_clone_args.
Setting kthread in fork_idle and kernel_thread.  Adding
user_mode_thread that works like kernel_thread except it does not set
kthread.  In fork only allocating the kthread_struct if .kthread is set.

I have looked at kernel/kthread.c and since commit 40966e31
("kthread: Ensure struct kthread is present for all kthreads") there
have been no assumptions added that to_kthread or __to_kthread will
not return NULL.

There are a few callers of to_kthread or __to_kthread that assume a
non-NULL struct kthread pointer will be returned.  These functions are
kthread_data(), kthread_parmme(), kthread_exit(), kthread(),
kthread_park(), kthread_unpark(), kthread_stop().  All of those functions
can reasonably expected to be called when it is know that a task is a
kthread so that assumption seems reasonable.

Cc: stable@vger.kernel.org
Fixes: 40966e31 ("kthread: Ensure struct kthread is present for all kthreads")
Reported-by: Максим Кутявин <maximkabox13@gmail.com>
Link: https://lkml.kernel.org/r/20220506141512.516114-1-ebiederm@xmission.comSigned-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

Pull more tracing updates from Steven Rostedt:

 - Rename the staging files to give them some meaning. Just
   stage1,stag2,etc, does not show what they are for

 - Check for NULL from allocation in bootconfig

 - Hold event mutex for dyn_event call in user events

 - Mark user events to broken (to work on the API)

 - Remove eBPF updates from user events

 - Remove user events from uapi header to keep it from being installed.

 - Move ftrace_graph_is_dead() into inline as it is called from hot
   paths and also convert it into a static branch.

* tag 'trace-v5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Move user_events.h temporarily out of include/uapi
  ftrace: Make ftrace_graph_is_dead() a static branch
  tracing: Set user_events to BROKEN
  tracing/user_events: Remove eBPF interfaces
  tracing/user_events: Hold event_mutex during dyn_event_add
  proc: bootconfig: Add null pointer check
  tracing: Rename the staging files for trace_events

Pull clk fix from Stephen Boyd:
 "A single revert to fix a boot regression seen when clk_put() started
  dropping rate range requests. It's best to keep various systems
  booting so we'll kick this out and try again next time"

* tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  Revert "clk: Drop the rate range on clk_put()"

Pull x86 fixes from Thomas Gleixner:
 "A set of x86 fixes and updates:

   - Make the prctl() for enabling dynamic XSTATE components correct so
     it adds the newly requested feature to the permission bitmap
     instead of overwriting it. Add a selftest which validates that.

   - Unroll string MMIO for encrypted SEV guests as the hypervisor
     cannot emulate it.

   - Handle supervisor states correctly in the FPU/XSTATE code so it
     takes the feature set of the fpstate buffer into account. The
     feature sets can differ between host and guest buffers. Guest
     buffers do not contain supervisor states. So far this was not an
     issue, but with enabling PASID it needs to be handled in the buffer
     offset calculation and in the permission bitmaps.

   - Avoid a gazillion of repeated CPUID invocations in by caching the
     values early in the FPU/XSTATE code.

   - Enable CONFIG_WERROR in x86 defconfig.

   - Make the X86 defconfigs more useful by adapting them to Y2022
     reality"

* tag 'x86-urgent-2022-04-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu/xstate: Consolidate size calculations
  x86/fpu/xstate: Handle supervisor states in XSTATE permissions
  x86/fpu/xsave: Handle compacted offsets correctly with supervisor states
  x86/fpu: Cache xfeature flags from CPUID
  x86/fpu/xsave: Initialize offset/size cache early
  x86/fpu: Remove unused supervisor only offsets
  x86/fpu: Remove redundant XCOMP_BV initialization
  x86/sev: Unroll string mmio with CC_ATTR_GUEST_UNROLL_STRING_IO
  x86/config: Make the x86 defconfigs a bit more usable
  x86/defconfig: Enable WERROR
  selftests/x86/amx: Update the ARCH_REQ_XCOMP_PERM test
  x86/fpu/xstate: Fix the ARCH_REQ_XCOMP_PERM implementation

Pull RT signal fix from Thomas Gleixner:
 "Revert the RT related signal changes. They need to be reworked and
  generalized"

* tag 'core-urgent-2022-04-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Revert "signal, x86: Delay calling signals in atomic on RT enabled kernels"

Pull more dma-mapping updates from Christoph Hellwig:

 - fix a regression in dma remap handling vs AMD memory encryption (me)

 - finally kill off the legacy PCI DMA API (Christophe JAILLET)

* tag 'dma-mapping-5.18-1' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: move pgprot_decrypted out of dma_pgprot
  PCI/doc: cleanup references to the legacy PCI DMA API
  PCI: Remove the deprecated "pci-dma-compat.h" API

Pull ARM fixes from Russell King:

 - avoid unnecessary rebuilds for library objects

 - fix return value of __setup handlers

 - fix invalid input check for "crashkernel=" kernel option

 - silence KASAN warnings in unwind_frame

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 9191/1: arm/stacktrace, kasan: Silence KASAN warnings in unwind_frame()
  ARM: 9190/1: kdump: add invalid input check for 'crashkernel=0'
  ARM: 9187/1: JIVE: fix return value of __setup handler
  ARM: 9189/1: decompressor: fix unneeded rebuilds of library objects

This reverts commit 7dabfa2b. There are
multiple reports that this breaks boot on various systems. The common
theme is that orphan clks are having rates set on them when that isn't
expected. Let's revert it out for now so that -rc1 boots.
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reported-by: Tony Lindgren <tony@atomide.com>
Reported-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Link: https://lore.kernel.org/r/366a0232-bb4a-c357-6aa8-636e398e05eb@samsung.com
Cc: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20220403022818.39572-1-sboyd@kernel.org

Merge tag 'perf-tools-for-v5.18-2022-04-02' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux

Pull more perf tools updates from Arnaldo Carvalho de Melo:

 - Avoid SEGV if core.cpus isn't set in 'perf stat'.

 - Stop depending on .git files for building PERF-VERSION-FILE, used in
   'perf --version', fixing some perf tools build scenarios.

 - Convert tracepoint.py example to python3.

 - Update UAPI header copies from the kernel sources: socket,
   mman-common, msr-index, KVM, i915 and cpufeatures.

 - Update copy of libbpf's hashmap.c.

 - Directly return instead of using local ret variable in
   evlist__create_syswide_maps(), found by coccinelle.

* tag 'perf-tools-for-v5.18-2022-04-02' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
  perf python: Convert tracepoint.py example to python3
  perf evlist: Directly return instead of using local ret variable
  perf cpumap: More cpu map reuse by merge.
  perf cpumap: Add is_subset function
  perf evlist: Rename cpus to user_requested_cpus
  perf tools: Stop depending on .git files for building PERF-VERSION-FILE
  tools headers cpufeatures: Sync with the kernel sources
  tools headers UAPI: Sync drm/i915_drm.h with the kernel sources
  tools headers UAPI: Sync linux/kvm.h with the kernel sources
  tools kvm headers arm64: Update KVM headers from the kernel sources
  tools arch x86: Sync the msr-index.h copy with the kernel sources
  tools headers UAPI: Sync asm-generic/mman-common.h with the kernel
  perf beauty: Update copy of linux/socket.h with the kernel sources
  perf tools: Update copy of libbpf's hashmap.c
  perf stat: Avoid SEGV if core.cpus isn't set

Merge tag 'kbuild-fixes-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Fix empty $(PYTHON) expansion.

 - Fix UML, which got broken by the attempt to suppress Clang warnings.

 - Fix warning message in modpost.

* tag 'kbuild-fixes-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  modpost: restore the warning message for missing symbol versions
  Revert "um: clang: Strip out -mno-global-merge from USER_CFLAGS"
  kbuild: Remove '-mno-global-merge'
  kbuild: fix empty ${PYTHON} in scripts/link-vmlinux.sh
  kconfig: remove stale comment about removed kconfig_print_symbol()

Pull MIPS fixes from Thomas Bogendoerfer:

 - build fix for gpio

 - fix crc32 build problems

 - check for failed memory allocations

* tag 'mips_5.18_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  MIPS: crypto: Fix CRC32 code
  MIPS: rb532: move GPIOD definition into C-files
  MIPS: lantiq: check the return value of kzalloc()
  mips: sgi-ip22: add a check for the return of kzalloc()

Pull kvm fixes from Paolo Bonzini:

 - Only do MSR filtering for MSRs accessed by rdmsr/wrmsr

 - Documentation improvements

 - Prevent module exit until all VMs are freed

 - PMU Virtualization fixes

 - Fix for kvm_irq_delivery_to_apic_fast() NULL-pointer dereferences

 - Other miscellaneous bugfixes

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (42 commits)
  KVM: x86: fix sending PV IPI
  KVM: x86/mmu: do compare-and-exchange of gPTE via the user address
  KVM: x86: Remove redundant vm_entry_controls_clearbit() call
  KVM: x86: cleanup enter_rmode()
  KVM: x86: SVM: fix tsc scaling when the host doesn't support it
  kvm: x86: SVM: remove unused defines
  KVM: x86: SVM: move tsc ratio definitions to svm.h
  KVM: x86: SVM: fix avic spec based definitions again
  KVM: MIPS: remove reference to trap&emulate virtualization
  KVM: x86: document limitations of MSR filtering
  KVM: x86: Only do MSR filtering when access MSR by rdmsr/wrmsr
  KVM: x86/emulator: Emulate RDPID only if it is enabled in guest
  KVM: x86/pmu: Fix and isolate TSX-specific performance event logic
  KVM: x86: mmu: trace kvm_mmu_set_spte after the new SPTE was set
  KVM: x86/svm: Clear reserved bits written to PerfEvtSeln MSRs
  KVM: x86: Trace all APICv inhibit changes and capture overall status
  KVM: x86: Add wrappers for setting/clearing APICv inhibits
  KVM: x86: Make APICv inhibit reasons an enum and cleanup naming
  KVM: X86: Handle implicit supervisor access with SMAP
  KVM: X86: Rename variable smap to not_smap in permission_fault()
  ...

This log message was accidentally chopped off.

I was wondering why this happened, but checking the ML log, Mark
precisely followed my suggestion [1].

I just used "..." because I was too lazy to type the sentence fully.
Sorry for the confusion.

[1]: https://lore.kernel.org/all/CAK7LNAR6bXXk9-ZzZYpTqzFqdYbQsZHmiWspu27rtsFxvfRuVA@mail.gmail.com/

Fixes: 4a679593 ("kbuild: modpost: Explicitly warn about unprototyped symbols")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

Pull block driver fix from Jens Axboe:
 "Got two reports on nbd spewing warnings on load now, which is a
  regression from a commit that went into your tree yesterday.

  Revert the problematic change for now"

* tag 'for-5.18/drivers-2022-04-02' of git://git.kernel.dk/linux-block:
  Revert "nbd: fix possible overflow on 'first_minor' in nbd_dev_add()"

Pull pci fix from Bjorn Helgaas:

 - Fix Hyper-V "defined but not used" build issue added during merge
   window (YueHaibing)

* tag 'pci-v5.18-changes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: hv: Remove unused hv_set_msi_entry_from_desc()

Merge tag 'tag-chrome-platform-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux

Pull chrome platform updates from Benson Leung:
 "cros_ec_typec:

   - Check for EC device - Fix a crash when using the cros_ec_typec
     driver on older hardware not capable of typec commands

   - Make try power role optional

   - Mux configuration reorganization series from Prashant

  cros_ec_debugfs:

   - Fix use after free. Thanks Tzung-bi

  sensorhub:

   - cros_ec_sensorhub fixup - Split trace include file

  misc:

   - Add new mailing list for chrome-platform development:

	chrome-platform@lists.linux.dev

     Now with patchwork!"

* tag 'tag-chrome-platform-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux:
  platform/chrome: cros_ec_debugfs: detach log reader wq from devm
  platform: chrome: Split trace include file
  platform/chrome: cros_ec_typec: Update mux flags during partner removal
  platform/chrome: cros_ec_typec: Configure muxes at start of port update
  platform/chrome: cros_ec_typec: Get mux state inside configure_mux
  platform/chrome: cros_ec_typec: Move mux flag checks
  platform/chrome: cros_ec_typec: Check for EC device
  platform/chrome: cros_ec_typec: Make try power role optional
  MAINTAINERS: platform-chrome: Add new chrome-platform@lists.linux.dev list

This reverts commit 6d35d04a.

Both Gabriel and Borislav report that this commit casues a regression
with nbd:

sysfs: cannot create duplicate filename '/dev/block/43:0'

Revert it before 5.18-rc1 and we'll investigage this separately in
due time.

Link: https://lore.kernel.org/all/YkiJTnFOt9bTv6A2@zn.tnic/Reported-by: Gabriel L. Somlo <somlo@cmu.edu>
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Commit 7ea1a012 ("watch_queue: Free the alloc bitmap when the
watch_queue is torn down") took care of the bitmap, but not the page
array.

  BUG: memory leak
  unreferenced object 0xffff88810d9bc140 (size 32):
  comm "syz-executor335", pid 3603, jiffies 4294946994 (age 12.840s)
  hex dump (first 32 bytes):
    40 a7 40 04 00 ea ff ff 00 00 00 00 00 00 00 00  @.@.............
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
     kmalloc_array include/linux/slab.h:621 [inline]
     kcalloc include/linux/slab.h:652 [inline]
     watch_queue_set_size+0x12f/0x2e0 kernel/watch_queue.c:251
     pipe_ioctl+0x82/0x140 fs/pipe.c:632
     vfs_ioctl fs/ioctl.c:51 [inline]
     __do_sys_ioctl fs/ioctl.c:874 [inline]
     __se_sys_ioctl fs/ioctl.c:860 [inline]
     __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:860
     do_syscall_x64 arch/x86/entry/common.c:50 [inline]

Reported-by: syzbot+25ea042ae28f3888727a@syzkaller.appspotmail.com
Fixes: c73be61c ("pipe: Add general notification queue support")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/r/20220322004654.618274-1-eric.dumazet@gmail.com/Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

After being merged, user_events become more visible to a wider audience
that have concerns with the current API.

It is too late to fix this for this release, but instead of a full
revert, just mark it as BROKEN (which prevents it from being selected in
make config).  Then we can work finding a better API.  If that fails,
then it will need to be completely reverted.

To not have the code silently bitrot, still allow building it with
COMPILE_TEST.

And to prevent the uapi header from being installed, then later changed,
and then have an old distro user space see the old version, move the
header file out of the uapi directory.

Surround the include with CONFIG_COMPILE_TEST to the current location,
but when the BROKEN tag is taken off, it will use the uapi directory,
and fail to compile.  This is a good way to remind us to move the header
back.

Link: https://lore.kernel.org/all/20220330155835.5e1f6669@gandalf.local.home
Link: https://lkml.kernel.org/r/20220330201755.29319-1-mathieu.desnoyers@efficios.comSuggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

While user_events API is under development and has been marked for broken
to not let the API become fixed, move the header file out of the uapi
directory. This is to prevent it from being installed, then later changed,
and then have an old distro user space update with a new kernel, where
applications see the user_events being available, but the old header is in
place, and then they get compiled incorrectly.

Also, surround the include with CONFIG_COMPILE_TEST to the current
location, but when the BROKEN tag is taken off, it will use the uapi
directory, and fail to compile. This is a good way to remind us to move
the header back.

Link: https://lore.kernel.org/all/20220330155835.5e1f6669@gandalf.local.home
Link: https://lkml.kernel.org/r/20220330201755.29319-1-mathieu.desnoyers@efficios.com
Link: https://lkml.kernel.org/r/20220401143903.188384f3@gandalf.local.homeSuggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

ftrace_graph_is_dead() is used on hot paths, it just reads a variable
in memory and is not worth suffering function call constraints.

For instance, at entry of prepare_ftrace_return(), inlining it avoids
saving prepare_ftrace_return() parameters to stack and restoring them
after calling ftrace_graph_is_dead().

While at it using a static branch is even more performant and is
rather well adapted considering that the returned value will almost
never change.

Inline ftrace_graph_is_dead() and replace 'kill_ftrace_graph' bool
by a static branch.

The performance improvement is noticeable.

Link: https://lkml.kernel.org/r/e0411a6a0ed3eafff0ad2bc9cd4b0e202b4617df.1648623570.git.christophe.leroy@csgroup.euSigned-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

After being merged, user_events become more visible to a wider audience
that have concerns with the current API. It is too late to fix this for
this release, but instead of a full revert, just mark it as BROKEN (which
prevents it from being selected in make config). Then we can work finding
a better API. If that fails, then it will need to be completely reverted.

Link: https://lore.kernel.org/all/2059213643.196683.1648499088753.JavaMail.zimbra@efficios.com/
Link: https://lkml.kernel.org/r/20220330155835.5e1f6669@gandalf.local.homeSigned-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Remove eBPF interfaces within user_events to ensure they are fully
reviewed.

Link: https://lore.kernel.org/all/20220329165718.GA10381@kbox/
Link: https://lkml.kernel.org/r/20220329173051.10087-1-beaub@linux.microsoft.comSuggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Make sure the event_mutex is properly held during dyn_event_add call.
This is required when adding dynamic events.

Link: https://lkml.kernel.org/r/20220328223225.1992-1-beaub@linux.microsoft.comReported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

kzalloc is a memory allocation function which can return NULL when some
internal memory errors happen. It is safer to add null pointer check.

Link: https://lkml.kernel.org/r/20220329104004.2376879-1-lv.ruyi@zte.com.cn

Cc: stable@vger.kernel.org
Fixes: c1a3c360 ("proc: bootconfig: Add /proc/bootconfig to show boot config list")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

When looking for implementation of different phases of the creation of the
TRACE_EVENT() macro, it is pretty useless when all helper macro
redefinitions are in files labeled "stageX_defines.h". Rename them to
state which phase the files are for. For instance, when looking for the
defines that are used to create the event fields, seeing
"stage4_event_fields.h" gives the developer a good idea that the defines
are in that file.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

If apic_id is less than min, and (max - apic_id) is greater than
KVM_IPI_CLUSTER_SIZE, then the third check condition is satisfied but
the new apic_id does not fit the bitmask.  In this case __send_ipi_mask
should send the IPI.

This is mostly theoretical, but it can happen if the apic_ids on three
iterations of the loop are for example 1, KVM_IPI_CLUSTER_SIZE, 0.

Fixes: aaffcfd1 ("KVM: X86: Implement PV IPIs in linux guest")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Message-Id: <1646814944-51801-1-git-send-email-lirongqing@baidu.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

FNAME(cmpxchg_gpte) is an inefficient mess.  It is at least decent if it
can go through get_user_pages_fast(), but if it cannot then it tries to
use memremap(); that is not just terribly slow, it is also wrong because
it assumes that the VM_PFNMAP VMA is contiguous.

The right way to do it would be to do the same thing as
hva_to_pfn_remapped() does since commit add6a0cd ("KVM: MMU: try to
fix up page faults before giving up", 2016-07-05), using follow_pte()
and fixup_user_fault() to determine the correct address to use for
memremap().  To do this, one could for example extract hva_to_pfn()
for use outside virt/kvm/kvm_main.c.  But really there is no reason to
do that either, because there is already a perfectly valid address to
do the cmpxchg() on, only it is a userspace address.  That means doing
user_access_begin()/user_access_end() and writing the code in assembly
to handle exceptions correctly.  Worse, the guest PTE can be 8-byte
even on i686 so there is the extra complication of using cmpxchg8b to
account for.  But at least it is an efficient mess.

(Thanks to Linus for suggesting improvement on the inline assembly).
Reported-by: Qiuhao Li <qiuhao@sysec.org>
Reported-by: Gaoning Pan <pgn@zju.edu.cn>
Reported-by: Yongkang Jia <kangel@zju.edu.cn>
Reported-by: syzbot+6cde2282daa792c49ab8@syzkaller.appspotmail.com
Debugged-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Tested-by: Maxim Levitsky <mlevitsk@redhat.com>
Cc: stable@vger.kernel.org
Fixes: bd53cb35 ("X86/KVM: Handle PFNs outside of kernel reach when touching GPTEs")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

When emulating exit from long mode, EFER_LMA is cleared with
vmx_set_efer().  This will already unset the VM_ENTRY_IA32E_MODE control
bit as requested by SDM, so there is no need to unset VM_ENTRY_IA32E_MODE
again in exit_lmode() explicitly.  In case EFER isn't supported by
hardware, long mode isn't supported, so exit_lmode() cannot be reached.

Note that, thanks to the shadow controls mechanism, this change doesn't
eliminate vmread or vmwrite.
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Message-Id: <20220311102643.807507-3-zhenzhong.duan@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

vmx_set_efer() sets uret->data but, in fact if the value of uret->data
will be used vmx_setup_uret_msrs() will have rewritten it with the value
returned by update_transition_efer().  uret->data is consumed if and only
if uret->load_into_hardware is true, and vmx_setup_uret_msrs() takes care
of (a) updating uret->data before setting uret->load_into_hardware to true
(b) setting uret->load_into_hardware to false if uret->data isn't updated.

Opportunistically use "vmx" directly instead of redoing to_vmx().
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Message-Id: <20220311102643.807507-2-zhenzhong.duan@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

It was decided that when TSC scaling is not supported,
the virtual MSR_AMD64_TSC_RATIO should still have the default '1.0'
value.

However in this case kvm_max_tsc_scaling_ratio is not set,
which breaks various assumptions.

Fix this by always calculating kvm_max_tsc_scaling_ratio regardless of
host support.  For consistency, do the same for VMX.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220322172449.235575-8-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Remove some unused #defines from svm.c
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220322172449.235575-7-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Another piece of SVM spec which should be in the header file
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220322172449.235575-6-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Due to wrong rebase, commit
4a204f78 ("KVM: SVM: Allow AVIC support on system w/ physical APIC ID > 255")

moved avic spec #defines back to avic.c.

Move them back, and while at it extend AVIC_DOORBELL_PHYSICAL_ID_MASK to 12
bits as well (it will be used in nested avic)
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220322172449.235575-5-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220313140522.1307751-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

MSR filtering requires an exit to userspace that is hard to implement and
would be very slow in the case of nested VMX vmexit and vmentry MSR
accesses.  Document the limitation.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>