Pull sound fixes from Takashi Iwai:
 "Just a few small fixes:

   - A regression fix for HDMI audio on HD-audio AMD codecs

   - Fixes for LINE6 MIDI handling

   - HD-audio quirk for Dell laptops"

* tag 'sound-6.2-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda/hdmi: Static PCM mapping again with AMD HDMI codecs
  ALSA: hda/realtek: Apply dual codec fixup for Dell Latitude laptops
  ALSA: line6: fix stack overflow in line6_midi_transmit
  ALSA: line6: correct midi status byte when receiving data from podxt

Pull block fixes from Jens Axboe:
 "Mostly just NVMe, but also a single fixup for BFQ for a regression
  that happened during the merge window. In detail:

   - NVMe pull requests via Christoph:
      - Fix doorbell buffer value endianness (Klaus Jensen)
      - Fix Linux vs NVMe page size mismatch (Keith Busch)
      - Fix a potential use memory access beyong the allocation limit
        (Keith Busch)
      - Fix a multipath vs blktrace NULL pointer dereference (Yanjun
        Zhang)
      - Fix various problems in handling the Command Supported and
        Effects log (Christoph Hellwig)
      - Don't allow unprivileged passthrough of commands that don't
        transfer data but modify logical block content (Christoph
        Hellwig)
      - Add a features and quirks policy document (Christoph Hellwig)
      - Fix some really nasty code that was correct but made smatch
        complain (Sagi Grimberg)

   - Use-after-free regression in BFQ from this merge window (Yu)"

* tag 'block-6.2-2022-12-29' of git://git.kernel.dk/linux:
  nvme-auth: fix smatch warning complaints
  nvme: consult the CSE log page for unprivileged passthrough
  nvme: also return I/O command effects from nvme_command_effects
  nvmet: don't defer passthrough commands with trivial effects to the workqueue
  nvmet: set the LBCC bit for commands that modify data
  nvmet: use NVME_CMD_EFFECTS_CSUPP instead of open coding it
  nvme: fix the NVME_CMD_EFFECTS_CSE_MASK definition
  docs, nvme: add a feature and quirk policy document
  nvme-pci: update sqsize when adjusting the queue depth
  nvme: fix setting the queue depth in nvme_alloc_io_tag_set
  block, bfq: fix uaf for bfqq in bfq_exit_icq_bfqq
  nvme: fix multipath crash caused by flush request when blktrace is enabled
  nvme-pci: fix page size checks
  nvme-pci: fix mempool alloc size
  nvme-pci: fix doorbell buffer value endianness

Pull io_uring fixes from Jens Axboe:

 - Two fixes for mutex grabbing when the task state is != TASK_RUNNING
   (me)

 - Check for invalid opcode in io_uring_register() a bit earlier, to
   avoid going through the quiesce machinery just to return -EINVAL
   later in the process (me)

 - Fix for the uapi io_uring header, skipping including time_types.h
   when necessary (Stefan)

* tag 'io_uring-6.2-2022-12-29' of git://git.kernel.dk/linux:
  uapi:io_uring.h: allow linux/time_types.h to be skipped
  io_uring: check for valid register opcode earlier
  io_uring/cancel: re-grab ctx mutex after finishing wait
  io_uring: finish waiting before flushing overflow entries

Merge tag 'linux-kselftest-kunit-fixes-6.2-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull KUnit fix from Shuah Khan:

 - alloc_string_stream_fragment() error path fix to free before
   returning a failure.

* tag 'linux-kselftest-kunit-fixes-6.2-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  kunit: alloc_string_stream_fragment error handling bug fix

Pull kvm fixes from Paolo Bonzini:
 "Changes that were posted too late for 6.1, or after the release.

  x86:

   - several fixes to nested VMX execution controls

   - fixes and clarification to the documentation for Xen emulation

   - do not unnecessarily release a pmu event with zero period

   - MMU fixes

   - fix Coverity warning in kvm_hv_flush_tlb()

  selftests:

   - fixes for the ucall mechanism in selftests

   - other fixes mostly related to compilation with clang"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (41 commits)
  KVM: selftests: restore special vmmcall code layout needed by the harness
  Documentation: kvm: clarify SRCU locking order
  KVM: x86: fix deadlock for KVM_XEN_EVTCHN_RESET
  KVM: x86/xen: Documentation updates and clarifications
  KVM: x86/xen: Add KVM_XEN_INVALID_GPA and KVM_XEN_INVALID_GFN to uapi
  KVM: x86/xen: Simplify eventfd IOCTLs
  KVM: x86/xen: Fix SRCU/RCU usage in readers of evtchn_ports
  KVM: x86/xen: Use kvm_read_guest_virt() instead of open-coding it badly
  KVM: x86/xen: Fix memory leak in kvm_xen_write_hypercall_page()
  KVM: Delete extra block of "};" in the KVM API documentation
  kvm: x86/mmu: Remove duplicated "be split" in spte.h
  kvm: Remove the unused macro KVM_MMU_READ_{,UN}LOCK()
  MAINTAINERS: adjust entry after renaming the vmx hyperv files
  KVM: selftests: Mark correct page as mapped in virt_map()
  KVM: arm64: selftests: Don't identity map the ucall MMIO hole
  KVM: selftests: document the default implementation of vm_vaddr_populate_bitmap
  KVM: selftests: Use magic value to signal ucall_alloc() failure
  KVM: selftests: Disable "gnu-variable-sized-type-not-at-end" warning
  KVM: selftests: Include lib.mk before consuming $(CC)
  KVM: selftests: Explicitly disable builtins for mem*() overrides
  ...

Pull NVMe fixes from Christoph:

"nvme fixes for Linux 6.2

 - fix various problems in handling the Command Supported and Effects log
   (Christoph Hellwig)
 - don't allow unprivileged passthrough of commands that don't transfer
   data but modify logical block content (Christoph Hellwig)
 - add a features and quirks policy document (Christoph Hellwig)
 - fix some really nasty code that was correct but made smatch complain
   (Sagi Grimberg)"

* tag 'nvme-6.2-2022-12-29' of git://git.infradead.org/nvme:
  nvme-auth: fix smatch warning complaints
  nvme: consult the CSE log page for unprivileged passthrough
  nvme: also return I/O command effects from nvme_command_effects
  nvmet: don't defer passthrough commands with trivial effects to the workqueue
  nvmet: set the LBCC bit for commands that modify data
  nvmet: use NVME_CMD_EFFECTS_CSUPP instead of open coding it
  nvme: fix the NVME_CMD_EFFECTS_CSE_MASK definition
  docs, nvme: add a feature and quirk policy document

When initializing auth context, there may be no secrets passed
by the user. Make return code explicit when returning successfully.

smatch warnings:
drivers/nvme/host/auth.c:950 nvme_auth_init_ctrl() warn: missing error code? 'ret'
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Commands like Write Zeros can change the contents of a namespaces without
actually transferring data.  To protect against this, check the Commands
Supported and Effects log is supported by the controller for any
unprivileg command passthrough and refuse unprivileged passthrough if the
command has any effects that can change data or metadata.

Note: While the Commands Support and Effects log page has only been
mandatory since NVMe 2.0, it is widely supported because Windows requires
it for any command passthrough from userspace.

Fixes: e4fbcf32 ("nvme: identify-namespace without CAP_SYS_ADMIN")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>

To be able to use the Commands Supported and Effects Log for allowing
unprivileged passtrough, it needs to be corretly reported for I/O
commands as well.  Return the I/O command effects from
nvme_command_effects, and also add a default list of effects for the
NVM command set.  For other command sets, the Commands Supported and
Effects log is required to be present already.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>

Mask out the "Command Supported" and "Logical Block Content Change" bits
and only defer execution of commands that have non-trivial effects to
the workqueue for synchronous execution.  This allows to execute admin
commands asynchronously on controllers that provide a Command Supported
and Effects log page, and will keep allowing to execute Write commands
asynchronously once command effects on I/O commands are taken into
account.

Fixes: c1fef73f ("nvmet: add passthru code to process commands")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>

Write, Write Zeroes, Zone append and a Zone Reset through
Zone Management Send modify the logical block content of a namespace,
so make sure the LBCC bit is reported for them.

Fixes: b5d0b38c0475 ("nvmet: add Command Set Identifier support")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>

Use NVME_CMD_EFFECTS_CSUPP instead of open coding it and assign a
single value to multiple array entries instead of repeated assignments.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>

3 << 16 does not generate the correct mask for bits 16, 17 and 18.
Use the GENMASK macro to generate the correct mask instead.

Fixes: 84fef62d ("nvme: check admin passthru command effects")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>

This adds a document about what specification features are supported by
the Linux NVMe driver, and what qualifies for a quirk if an implementation
has problems following the specification.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>

The recent code refactoring for HD-audio HDMI codec driver caused a
regression on AMD/ATI HDMI codecs; namely, PulseAudioand pipewire
don't recognize HDMI outputs any longer while the direct output via
ALSA raw access still works.

The problem turned out that, after the code refactoring, the driver
assumes only the dynamic PCM assignment, and when a PCM stream that
still isn't assigned to any pin gets opened, the driver tries to
assign any free converter to the PCM stream.  This behavior is OK for
Intel and other codecs, as they have arbitrary connections between
pins and converters.  OTOH, on AMD chips that have a 1:1 mapping
between pins and converters, this may end up with blocking the open of
the next PCM stream for the pin that is tied with the formerly taken
converter.

Also, with the code refactoring, more PCM streams are exposed than
necessary as we assume all converters can be used, while this isn't
true for AMD case.  This may change the PCM stream assignment and
confuse users as well.

This patch fixes those problems by:

- Introducing a flag spec->static_pcm_mapping, and if it's set, the
  driver applies the static mapping between pins and converters at the
  probe time
- Limiting the number of PCM streams per pins, too; this avoids the
  superfluous PCM streams

Fixes: ef6f5494 ("ALSA: hda/hdmi: Use only dynamic PCM device allocation")
Cc: <stable@vger.kernel.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216836Co-developed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20221228125714.16329-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

x86:

* several fixes to nested VMX execution controls

* fixes and clarification to the documentation for Xen emulation

* do not unnecessarily release a pmu event with zero period

* MMU fixes

* fix Coverity warning in kvm_hv_flush_tlb()

selftests:

* fixes for the ucall mechanism in selftests

* other fixes mostly related to compilation with clang

Commit 8fda37cf ("KVM: selftests: Stuff RAX/RCX with 'safe' values
in vmmcall()/vmcall()", 2022-11-21) broke the svm_nested_soft_inject_test
because it placed a "pop rbp" instruction after vmmcall.  While this is
correct and mimics what is done in the VMX case, this particular test
expects a ud2 instruction right after the vmmcall, so that it can skip
over it in the L1 part of the test.

Inline a suitably-modified version of vmmcall() to restore the
functionality of the test.

Fixes: 8fda37cf ("KVM: selftests: Stuff RAX/RCX with 'safe' values in vmmcall()/vmcall()"
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221130181147.9911-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Currently only the locking order of SRCU vs kvm->slots_arch_lock
and kvm->slots_lock is documented.  Extend this to kvm->lock
since Xen emulation got it terribly wrong.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

While KVM_XEN_EVTCHN_RESET is usually called with no vCPUs running,
if that happened it could cause a deadlock.  This is due to
kvm_xen_eventfd_reset() doing a synchronize_srcu() inside
a kvm->lock critical section.

To avoid this, first collect all the evtchnfd objects in an
array and free all of them once the kvm->lock critical section
is over and th SRCU grace period has expired.
Reported-by: Michal Luczaj <mhal@rbox.co>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

include/uapi/linux/io_uring.h is synced 1:1 into
liburing:src/include/liburing/io_uring.h.

liburing has a configure check to detect the need for
linux/time_types.h. It can opt-out by defining
UAPI_LINUX_IO_URING_H_SKIP_LINUX_TIME_TYPES_H

Fixes: 78a861b9 ("io_uring: add sync cancelation API through io_uring_register()")
Link: https://github.com/axboe/liburing/issues/708
Link: https://github.com/axboe/liburing/pull/709
Link: https://lore.kernel.org/io-uring/20221115212614.1308132-1-ammar.faizi@intel.com/T/#m9f5dd571cd4f6a5dee84452dbbca3b92ba7a4091
CC: Jens Axboe <axboe@kernel.dk>
Cc: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Link: https://lore.kernel.org/r/7071a0a1d751221538b20b63f9160094fc7e06f4.1668630247.git.metze@samba.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

Most notably, the KVM_XEN_EVTCHN_RESET feature had escaped documentation
entirely. Along with how to turn most stuff off on SHUTDOWN_soft_reset.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20221226120320.1125390-6-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

These are (uint64_t)-1 magic values are a userspace ABI, allowing the
shared info pages and other enlightenments to be disabled. This isn't
a Xen ABI because Xen doesn't let the guest turn these off except with
the full SHUTDOWN_soft_reset mechanism. Under KVM, the userspace VMM is
expected to handle soft reset, and tear down the kernel parts of the
enlightenments accordingly.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20221226120320.1125390-5-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Port number is validated in kvm_xen_setattr_evtchn().
Remove superfluous checks in kvm_xen_eventfd_assign() and
kvm_xen_eventfd_update().
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Message-Id: <20221222203021.1944101-3-mhal@rbox.co>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20221226120320.1125390-4-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The evtchnfd structure itself must be protected by either kvm->lock or
SRCU. Use the former in kvm_xen_eventfd_update(), since the lock is
being taken anyway; kvm_xen_hcall_evtchn_send() instead is a reader and
does not need kvm->lock, and is called in SRCU critical section from the
kvm_x86_handle_exit function.

It is also important to use rcu_read_{lock,unlock}() in
kvm_xen_hcall_evtchn_send(), because idr_remove() will *not*
use synchronize_srcu() to wait for readers to complete.

Remove a superfluous if (kvm) check before calling synchronize_srcu()
in kvm_xen_eventfd_deassign() where kvm has been dereferenced already.
Co-developed-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20221226120320.1125390-3-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

In particular, we shouldn't assume that being contiguous in guest virtual
address space means being contiguous in guest *physical* address space.

In dropping the manual calls to kvm_mmu_gva_to_gpa_system(), also drop
the srcu_read_lock() that was around them. All call sites are reached
from kvm_xen_hypercall() which is called from the handle_exit function
with the read lock already held.

       53639526 ("KVM: x86/xen: handle PV timers oneshot mode")
       1a65105a ("KVM: x86/xen: handle PV spinlocks slowpath")

Fixes: 2fd6df2f ("KVM: x86/xen: intercept EVTCHNOP_send from guests")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20221226120320.1125390-2-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Release page irrespectively of kvm_vcpu_write_guest() return value.
Suggested-by: Paul Durrant <paul@xen.org>
Fixes: 23200b7a ("KVM: x86/xen: intercept xen hypercalls if enabled")
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Message-Id: <20221220151454.712165-1-mhal@rbox.co>
Reviewed-by: Paul Durrant <paul@xen.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20221226120320.1125390-1-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Delete an extra block of code/documentation that snuck in when KVM's
documentation was converted to ReST format.

Fixes: 106ee47d ("docs: kvm: Convert api.txt to ReST format")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221207003637.2041211-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

"be split be split" -> "be split"
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Message-Id: <20221207120505.9175-1-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

No code is using KVM_MMU_READ_LOCK() or KVM_MMU_READ_UNLOCK().  They
used to be in virt/kvm/pfncache.c:

                KVM_MMU_READ_LOCK(kvm);
                retry = mmu_notifier_retry_hva(kvm, mmu_seq, uhva);
                KVM_MMU_READ_UNLOCK(kvm);

However, since 58cd407c ("KVM: Fix multiple races in gfn=>pfn cache
refresh", 2022-05-25) the code is only relying on the MMU notifier's
invalidation count and sequence number.
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Message-Id: <20221207120617.9409-1-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Commit a789aeba ("KVM: VMX: Rename "vmx/evmcs.{ch}" to
"vmx/hyperv.{ch}"") renames the VMX specific Hyper-V files, but does not
adjust the entry in MAINTAINERS.

Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a
broken reference.

Repair this file reference in KVM X86 HYPER-V (KVM/hyper-v).
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Fixes: a789aeba ("KVM: VMX: Rename "vmx/evmcs.{ch}" to "vmx/hyperv.{ch}"")
Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221205082044.10141-1-lukas.bulwahn@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The loop marks vaddr as mapped after incrementing it by page size,
thereby marking the *next* page as mapped. Set the bit in vpages_mapped
first instead.

Fixes: 56fc7732 ("KVM: selftests: Fill in vm->vpages_mapped bitmap in virt_map() too")
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Message-Id: <20221209015307.1781352-4-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Currently the ucall MMIO hole is placed immediately after slot0, which
is a relatively safe address in the PA space. However, it is possible
that the same address has already been used for something else (like the
guest program image) in the VA space. At least in my own testing,
building the vgic_irq test with clang leads to the MMIO hole appearing
underneath gicv3_ops.

Stop identity mapping the MMIO hole and instead find an unused VA to map
to it. Yet another subtle detail of the KVM selftests library is that
virt_pg_map() does not update vm->vpages_mapped. Switch over to
virt_map() instead to guarantee that the chosen VA isn't to something
else.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Message-Id: <20221209015307.1781352-6-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Explain the meaning of the bit manipulations of vm_vaddr_populate_bitmap.
These correspond to the "canonical addresses" of x86 and other
architectures, but that is not obvious.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Use a magic value to signal a ucall_alloc() failure instead of simply
doing GUEST_ASSERT().  GUEST_ASSERT() relies on ucall_alloc() and so a
failure puts the guest into an infinite loop.

Use -1 as the magic value, as a real ucall struct should never wrap.
Reported-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Disable gnu-variable-sized-type-not-at-end so that tests and libraries
can create overlays of variable sized arrays at the end of structs when
using a fixed number of entries, e.g. to get/set a single MSR.

It's possible to fudge around the warning, e.g. by defining a custom
struct that hardcodes the number of entries, but that is a burden for
both developers and readers of the code.

lib/x86_64/processor.c:664:19: warning: field 'header' with variable sized type 'struct kvm_msrs'
not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end]
                struct kvm_msrs header;
                                ^
lib/x86_64/processor.c:772:19: warning: field 'header' with variable sized type 'struct kvm_msrs'
not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end]
                struct kvm_msrs header;
                                ^
lib/x86_64/processor.c:787:19: warning: field 'header' with variable sized type 'struct kvm_msrs'
not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end]
                struct kvm_msrs header;
                                ^
3 warnings generated.

x86_64/hyperv_tlb_flush.c:54:18: warning: field 'hv_vp_set' with variable sized type 'struct hv_vpset'
not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end]
        struct hv_vpset hv_vp_set;
                        ^
1 warning generated.

x86_64/xen_shinfo_test.c:137:25: warning: field 'info' with variable sized type 'struct kvm_irq_routing'
not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end]
        struct kvm_irq_routing info;
                               ^
1 warning generated.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221213001653.3852042-12-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Include lib.mk before consuming $(CC) and document that lib.mk overwrites
$(CC) unless make was invoked with -e or $(CC) was specified after make
(which makes the environment override the Makefile).  Including lib.mk
after using it for probing, e.g. for -no-pie, can lead to weirdness.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221213001653.3852042-11-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Explicitly disable the compiler's builtin memcmp(), memcpy(), and
memset().  Because only lib/string_override.c is built with -ffreestanding,
the compiler reserves the right to do what it wants and can try to link the
non-freestanding code to its own crud.

  /usr/bin/x86_64-linux-gnu-ld: /lib/x86_64-linux-gnu/libc.a(memcmp.o): in function `memcmp_ifunc':
  (.text+0x0): multiple definition of `memcmp'; tools/testing/selftests/kvm/lib/string_override.o:
  tools/testing/selftests/kvm/lib/string_override.c:15: first defined here
  clang: error: linker command failed with exit code 1 (use -v to see invocation)

Fixes: 6b6f7148 ("KVM: selftests: Implement memcmp(), memcpy(), and memset() for guest use")
Reported-by: Aaron Lewis <aaronlewis@google.com>
Reported-by: Raghavendra Rao Ananta <rananta@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221213001653.3852042-10-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Probe -no-pie with the actual set of CFLAGS used to compile the tests,
clang whines about -no-pie being unused if the tests are compiled with
-static.

  clang: warning: argument unused during compilation: '-no-pie'
  [-Wunused-command-line-argument]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221213001653.3852042-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Make the main() functions in the probing code proper prototypes so that
compiling the probing code with more strict flags won't generate false
negatives.

  <stdin>:1:5: error: function declaration isn’t a prototype [-Werror=strict-prototypes]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221213001653.3852042-8-seanjc@google.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Rename UNAME_M to ARCH_DIR and explicitly set it directly for x86.  At
this point, the name of the arch directory really doesn't have anything
to do with `uname -m`, and UNAME_M is unnecessarily confusing given that
its purpose is purely to identify the arch specific directory.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221213001653.3852042-7-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>