<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/arm, branch v4.16-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'kvm-4.16-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm</title>
<updated>2018-02-10T21:16:35+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-02-10T21:16:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=15303ba5d1cd9b28d03a980456c0978c0ea3b208'/>
<id>15303ba5d1cd9b28d03a980456c0978c0ea3b208</id>
<content type='text'>
Pull KVM updates from Radim Krčmář:
 "ARM:

   - icache invalidation optimizations, improving VM startup time

   - support for forwarded level-triggered interrupts, improving
     performance for timers and passthrough platform devices

   - a small fix for power-management notifiers, and some cosmetic
     changes

  PPC:

   - add MMIO emulation for vector loads and stores

   - allow HPT guests to run on a radix host on POWER9 v2.2 CPUs without
     requiring the complex thread synchronization of older CPU versions

   - improve the handling of escalation interrupts with the XIVE
     interrupt controller

   - support decrement register migration

   - various cleanups and bugfixes.

  s390:

   - Cornelia Huck passed maintainership to Janosch Frank

   - exitless interrupts for emulated devices

   - cleanup of cpuflag handling

   - kvm_stat counter improvements

   - VSIE improvements

   - mm cleanup

  x86:

   - hypervisor part of SEV

   - UMIP, RDPID, and MSR_SMI_COUNT emulation

   - paravirtualized TLB shootdown using the new KVM_VCPU_PREEMPTED bit

   - allow guests to see TOPOEXT, GFNI, VAES, VPCLMULQDQ, and more
     AVX512 features

   - show vcpu id in its anonymous inode name

   - many fixes and cleanups

   - per-VCPU MSR bitmaps (already merged through x86/pti branch)

   - stable KVM clock when nesting on Hyper-V (merged through
     x86/hyperv)"

* tag 'kvm-4.16-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (197 commits)
  KVM: PPC: Book3S: Add MMIO emulation for VMX instructions
  KVM: PPC: Book3S HV: Branch inside feature section
  KVM: PPC: Book3S HV: Make HPT resizing work on POWER9
  KVM: PPC: Book3S HV: Fix handling of secondary HPTEG in HPT resizing code
  KVM: PPC: Book3S PR: Fix broken select due to misspelling
  KVM: x86: don't forget vcpu_put() in kvm_arch_vcpu_ioctl_set_sregs()
  KVM: PPC: Book3S PR: Fix svcpu copying with preemption enabled
  KVM: PPC: Book3S HV: Drop locks before reading guest memory
  kvm: x86: remove efer_reload entry in kvm_vcpu_stat
  KVM: x86: AMD Processor Topology Information
  x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when running nested
  kvm: embed vcpu id to dentry of vcpu anon inode
  kvm: Map PFN-type memory regions as writable (if possible)
  x86/kvm: Make it compile on 32bit and with HYPYERVISOR_GUEST=n
  KVM: arm/arm64: Fixup userspace irqchip static key optimization
  KVM: arm/arm64: Fix userspace_irqchip_in_use counting
  KVM: arm/arm64: Fix incorrect timer_is_pending logic
  MAINTAINERS: update KVM/s390 maintainers
  MAINTAINERS: add Halil as additional vfio-ccw maintainer
  MAINTAINERS: add David as a reviewer for KVM/s390
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull KVM updates from Radim Krčmář:
 "ARM:

   - icache invalidation optimizations, improving VM startup time

   - support for forwarded level-triggered interrupts, improving
     performance for timers and passthrough platform devices

   - a small fix for power-management notifiers, and some cosmetic
     changes

  PPC:

   - add MMIO emulation for vector loads and stores

   - allow HPT guests to run on a radix host on POWER9 v2.2 CPUs without
     requiring the complex thread synchronization of older CPU versions

   - improve the handling of escalation interrupts with the XIVE
     interrupt controller

   - support decrement register migration

   - various cleanups and bugfixes.

  s390:

   - Cornelia Huck passed maintainership to Janosch Frank

   - exitless interrupts for emulated devices

   - cleanup of cpuflag handling

   - kvm_stat counter improvements

   - VSIE improvements

   - mm cleanup

  x86:

   - hypervisor part of SEV

   - UMIP, RDPID, and MSR_SMI_COUNT emulation

   - paravirtualized TLB shootdown using the new KVM_VCPU_PREEMPTED bit

   - allow guests to see TOPOEXT, GFNI, VAES, VPCLMULQDQ, and more
     AVX512 features

   - show vcpu id in its anonymous inode name

   - many fixes and cleanups

   - per-VCPU MSR bitmaps (already merged through x86/pti branch)

   - stable KVM clock when nesting on Hyper-V (merged through
     x86/hyperv)"

* tag 'kvm-4.16-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (197 commits)
  KVM: PPC: Book3S: Add MMIO emulation for VMX instructions
  KVM: PPC: Book3S HV: Branch inside feature section
  KVM: PPC: Book3S HV: Make HPT resizing work on POWER9
  KVM: PPC: Book3S HV: Fix handling of secondary HPTEG in HPT resizing code
  KVM: PPC: Book3S PR: Fix broken select due to misspelling
  KVM: x86: don't forget vcpu_put() in kvm_arch_vcpu_ioctl_set_sregs()
  KVM: PPC: Book3S PR: Fix svcpu copying with preemption enabled
  KVM: PPC: Book3S HV: Drop locks before reading guest memory
  kvm: x86: remove efer_reload entry in kvm_vcpu_stat
  KVM: x86: AMD Processor Topology Information
  x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when running nested
  kvm: embed vcpu id to dentry of vcpu anon inode
  kvm: Map PFN-type memory regions as writable (if possible)
  x86/kvm: Make it compile on 32bit and with HYPYERVISOR_GUEST=n
  KVM: arm/arm64: Fixup userspace irqchip static key optimization
  KVM: arm/arm64: Fix userspace_irqchip_in_use counting
  KVM: arm/arm64: Fix incorrect timer_is_pending logic
  MAINTAINERS: update KVM/s390 maintainers
  MAINTAINERS: add Halil as additional vfio-ccw maintainer
  MAINTAINERS: add David as a reviewer for KVM/s390
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'kbuild-v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild</title>
<updated>2018-02-10T03:32:41+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-02-10T03:32:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=9a61df9e5f7471fe5be3e02bd0bed726b2761a54'/>
<id>9a61df9e5f7471fe5be3e02bd0bed726b2761a54</id>
<content type='text'>
Pull more Kbuild updates from Masahiro Yamada:
 "Makefile changes:
   - enable unused-variable warning that was wrongly disabled for clang

  Kconfig changes:
   - warn about blank 'help' and fix existing instances
   - fix 'choice' behavior to not write out invisible symbols
   - fix misc weirdness

  Coccinell changes:
   - fix false positive of free after managed memory alloc detection
   - improve performance of NULL dereference detection"

* tag 'kbuild-v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (21 commits)
  kconfig: remove const qualifier from sym_expand_string_value()
  kconfig: add xrealloc() helper
  kconfig: send error messages to stderr
  kconfig: echo stdin to stdout if either is redirected
  kconfig: remove check_stdin()
  kconfig: remove 'config*' pattern from .gitignnore
  kconfig: show '?' prompt even if no help text is available
  kconfig: do not write choice values when their dependency becomes n
  coccinelle: deref_null: avoid useless computation
  coccinelle: devm_free: reduce false positives
  kbuild: clang: disable unused variable warnings only when constant
  kconfig: Warn if help text is blank
  nios2: kconfig: Remove blank help text
  arm: vt8500: kconfig: Remove blank help text
  MIPS: kconfig: Remove blank help text
  MIPS: BCM63XX: kconfig: Remove blank help text
  lib/Kconfig.debug: Remove blank help text
  Staging: rtl8192e: kconfig: Remove blank help text
  Staging: rtl8192u: kconfig: Remove blank help text
  mmc: kconfig: Remove blank help text
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull more Kbuild updates from Masahiro Yamada:
 "Makefile changes:
   - enable unused-variable warning that was wrongly disabled for clang

  Kconfig changes:
   - warn about blank 'help' and fix existing instances
   - fix 'choice' behavior to not write out invisible symbols
   - fix misc weirdness

  Coccinell changes:
   - fix false positive of free after managed memory alloc detection
   - improve performance of NULL dereference detection"

* tag 'kbuild-v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (21 commits)
  kconfig: remove const qualifier from sym_expand_string_value()
  kconfig: add xrealloc() helper
  kconfig: send error messages to stderr
  kconfig: echo stdin to stdout if either is redirected
  kconfig: remove check_stdin()
  kconfig: remove 'config*' pattern from .gitignnore
  kconfig: show '?' prompt even if no help text is available
  kconfig: do not write choice values when their dependency becomes n
  coccinelle: deref_null: avoid useless computation
  coccinelle: devm_free: reduce false positives
  kbuild: clang: disable unused variable warnings only when constant
  kconfig: Warn if help text is blank
  nios2: kconfig: Remove blank help text
  arm: vt8500: kconfig: Remove blank help text
  MIPS: kconfig: Remove blank help text
  MIPS: BCM63XX: kconfig: Remove blank help text
  lib/Kconfig.debug: Remove blank help text
  Staging: rtl8192e: kconfig: Remove blank help text
  Staging: rtl8192u: kconfig: Remove blank help text
  mmc: kconfig: Remove blank help text
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux</title>
<updated>2018-02-08T18:44:25+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-02-08T18:44:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c0136321924dd338bb8fc5661c4b0e27441a8d04'/>
<id>c0136321924dd338bb8fc5661c4b0e27441a8d04</id>
<content type='text'>
Pull more arm64 updates from Catalin Marinas:
 "As I mentioned in the last pull request, there's a second batch of
  security updates for arm64 with mitigations for Spectre/v1 and an
  improved one for Spectre/v2 (via a newly defined firmware interface
  API).

  Spectre v1 mitigation:

   - back-end version of array_index_mask_nospec()

   - masking of the syscall number to restrict speculation through the
     syscall table

   - masking of __user pointers prior to deference in uaccess routines

  Spectre v2 mitigation update:

   - using the new firmware SMC calling convention specification update

   - removing the current PSCI GET_VERSION firmware call mitigation as
     vendors are deploying new SMCCC-capable firmware

   - additional branch predictor hardening for synchronous exceptions
     and interrupts while in user mode

  Meltdown v3 mitigation update:

    - Cavium Thunder X is unaffected but a hardware erratum gets in the
      way. The kernel now starts with the page tables mapped as global
      and switches to non-global if kpti needs to be enabled.

  Other:

   - Theoretical trylock bug fixed"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (38 commits)
  arm64: Kill PSCI_GET_VERSION as a variant-2 workaround
  arm64: Add ARM_SMCCC_ARCH_WORKAROUND_1 BP hardening support
  arm/arm64: smccc: Implement SMCCC v1.1 inline primitive
  arm/arm64: smccc: Make function identifiers an unsigned quantity
  firmware/psci: Expose SMCCC version through psci_ops
  firmware/psci: Expose PSCI conduit
  arm64: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling
  arm64: KVM: Report SMCCC_ARCH_WORKAROUND_1 BP hardening support
  arm/arm64: KVM: Turn kvm_psci_version into a static inline
  arm/arm64: KVM: Advertise SMCCC v1.1
  arm/arm64: KVM: Implement PSCI 1.0 support
  arm/arm64: KVM: Add smccc accessors to PSCI code
  arm/arm64: KVM: Add PSCI_VERSION helper
  arm/arm64: KVM: Consolidate the PSCI include files
  arm64: KVM: Increment PC after handling an SMC trap
  arm: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
  arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
  arm64: entry: Apply BP hardening for suspicious interrupts from EL0
  arm64: entry: Apply BP hardening for high-priority synchronous exceptions
  arm64: futex: Mask __user pointers prior to dereference
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull more arm64 updates from Catalin Marinas:
 "As I mentioned in the last pull request, there's a second batch of
  security updates for arm64 with mitigations for Spectre/v1 and an
  improved one for Spectre/v2 (via a newly defined firmware interface
  API).

  Spectre v1 mitigation:

   - back-end version of array_index_mask_nospec()

   - masking of the syscall number to restrict speculation through the
     syscall table

   - masking of __user pointers prior to deference in uaccess routines

  Spectre v2 mitigation update:

   - using the new firmware SMC calling convention specification update

   - removing the current PSCI GET_VERSION firmware call mitigation as
     vendors are deploying new SMCCC-capable firmware

   - additional branch predictor hardening for synchronous exceptions
     and interrupts while in user mode

  Meltdown v3 mitigation update:

    - Cavium Thunder X is unaffected but a hardware erratum gets in the
      way. The kernel now starts with the page tables mapped as global
      and switches to non-global if kpti needs to be enabled.

  Other:

   - Theoretical trylock bug fixed"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (38 commits)
  arm64: Kill PSCI_GET_VERSION as a variant-2 workaround
  arm64: Add ARM_SMCCC_ARCH_WORKAROUND_1 BP hardening support
  arm/arm64: smccc: Implement SMCCC v1.1 inline primitive
  arm/arm64: smccc: Make function identifiers an unsigned quantity
  firmware/psci: Expose SMCCC version through psci_ops
  firmware/psci: Expose PSCI conduit
  arm64: KVM: Add SMCCC_ARCH_WORKAROUND_1 fast handling
  arm64: KVM: Report SMCCC_ARCH_WORKAROUND_1 BP hardening support
  arm/arm64: KVM: Turn kvm_psci_version into a static inline
  arm/arm64: KVM: Advertise SMCCC v1.1
  arm/arm64: KVM: Implement PSCI 1.0 support
  arm/arm64: KVM: Add smccc accessors to PSCI code
  arm/arm64: KVM: Add PSCI_VERSION helper
  arm/arm64: KVM: Consolidate the PSCI include files
  arm64: KVM: Increment PC after handling an SMC trap
  arm: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
  arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
  arm64: entry: Apply BP hardening for suspicious interrupts from EL0
  arm64: entry: Apply BP hardening for high-priority synchronous exceptions
  arm64: futex: Mask __user pointers prior to dereference
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'akpm' (patches from Andrew)</title>
<updated>2018-02-07T06:15:42+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-02-07T06:15:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=a2e5790d841658485d642196dbb0927303d6c22f'/>
<id>a2e5790d841658485d642196dbb0927303d6c22f</id>
<content type='text'>
Merge misc updates from Andrew Morton:

 - kasan updates

 - procfs

 - lib/bitmap updates

 - other lib/ updates

 - checkpatch tweaks

 - rapidio

 - ubsan

 - pipe fixes and cleanups

 - lots of other misc bits

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (114 commits)
  Documentation/sysctl/user.txt: fix typo
  MAINTAINERS: update ARM/QUALCOMM SUPPORT patterns
  MAINTAINERS: update various PALM patterns
  MAINTAINERS: update "ARM/OXNAS platform support" patterns
  MAINTAINERS: update Cortina/Gemini patterns
  MAINTAINERS: remove ARM/CLKDEV SUPPORT file pattern
  MAINTAINERS: remove ANDROID ION pattern
  mm: docs: add blank lines to silence sphinx "Unexpected indentation" errors
  mm: docs: fix parameter names mismatch
  mm: docs: fixup punctuation
  pipe: read buffer limits atomically
  pipe: simplify round_pipe_size()
  pipe: reject F_SETPIPE_SZ with size over UINT_MAX
  pipe: fix off-by-one error when checking buffer limits
  pipe: actually allow root to exceed the pipe buffer limits
  pipe, sysctl: remove pipe_proc_fn()
  pipe, sysctl: drop 'min' parameter from pipe-max-size converter
  kasan: rework Kconfig settings
  crash_dump: is_kdump_kernel can be boolean
  kernel/mutex: mutex_is_locked can be boolean
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Merge misc updates from Andrew Morton:

 - kasan updates

 - procfs

 - lib/bitmap updates

 - other lib/ updates

 - checkpatch tweaks

 - rapidio

 - ubsan

 - pipe fixes and cleanups

 - lots of other misc bits

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (114 commits)
  Documentation/sysctl/user.txt: fix typo
  MAINTAINERS: update ARM/QUALCOMM SUPPORT patterns
  MAINTAINERS: update various PALM patterns
  MAINTAINERS: update "ARM/OXNAS platform support" patterns
  MAINTAINERS: update Cortina/Gemini patterns
  MAINTAINERS: remove ARM/CLKDEV SUPPORT file pattern
  MAINTAINERS: remove ANDROID ION pattern
  mm: docs: add blank lines to silence sphinx "Unexpected indentation" errors
  mm: docs: fix parameter names mismatch
  mm: docs: fixup punctuation
  pipe: read buffer limits atomically
  pipe: simplify round_pipe_size()
  pipe: reject F_SETPIPE_SZ with size over UINT_MAX
  pipe: fix off-by-one error when checking buffer limits
  pipe: actually allow root to exceed the pipe buffer limits
  pipe, sysctl: remove pipe_proc_fn()
  pipe, sysctl: drop 'min' parameter from pipe-max-size converter
  kasan: rework Kconfig settings
  crash_dump: is_kdump_kernel can be boolean
  kernel/mutex: mutex_is_locked can be boolean
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>lib: optimize cpumask_next_and()</title>
<updated>2018-02-07T02:32:44+00:00</updated>
<author>
<name>Clement Courbet</name>
<email>courbet@google.com</email>
</author>
<published>2018-02-06T23:38:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=0ade34c37012ea5c516d9aa4d19a56e9f40a55ed'/>
<id>0ade34c37012ea5c516d9aa4d19a56e9f40a55ed</id>
<content type='text'>
We've measured that we spend ~0.6% of sys cpu time in cpumask_next_and().
It's essentially a joined iteration in search for a non-zero bit, which is
currently implemented as a lookup join (find a nonzero bit on the lhs,
lookup the rhs to see if it's set there).

Implement a direct join (find a nonzero bit on the incrementally built
join).  Also add generic bitmap benchmarks in the new `test_find_bit`
module for new function (see `find_next_and_bit` in [2] and [3] below).

For cpumask_next_and, direct benchmarking shows that it's 1.17x to 14x
faster with a geometric mean of 2.1 on 32 CPUs [1].  No impact on memory
usage.  Note that on Arm, the new pure-C implementation still outperforms
the old one that uses a mix of C and asm (`find_next_bit`) [3].

[1] Approximate benchmark code:

```
  unsigned long src1p[nr_cpumask_longs] = {pattern1};
  unsigned long src2p[nr_cpumask_longs] = {pattern2};
  for (/*a bunch of repetitions*/) {
    for (int n = -1; n &lt;= nr_cpu_ids; ++n) {
      asm volatile("" : "+rm"(src1p)); // prevent any optimization
      asm volatile("" : "+rm"(src2p));
      unsigned long result = cpumask_next_and(n, src1p, src2p);
      asm volatile("" : "+rm"(result));
    }
  }
```

Results:
pattern1    pattern2     time_before/time_after
0x0000ffff  0x0000ffff   1.65
0x0000ffff  0x00005555   2.24
0x0000ffff  0x00001111   2.94
0x0000ffff  0x00000000   14.0
0x00005555  0x0000ffff   1.67
0x00005555  0x00005555   1.71
0x00005555  0x00001111   1.90
0x00005555  0x00000000   6.58
0x00001111  0x0000ffff   1.46
0x00001111  0x00005555   1.49
0x00001111  0x00001111   1.45
0x00001111  0x00000000   3.10
0x00000000  0x0000ffff   1.18
0x00000000  0x00005555   1.18
0x00000000  0x00001111   1.17
0x00000000  0x00000000   1.25
-----------------------------
               geo.mean  2.06

[2] test_find_next_bit, X86 (skylake)

 [ 3913.477422] Start testing find_bit() with random-filled bitmap
 [ 3913.477847] find_next_bit: 160868 cycles, 16484 iterations
 [ 3913.477933] find_next_zero_bit: 169542 cycles, 16285 iterations
 [ 3913.478036] find_last_bit: 201638 cycles, 16483 iterations
 [ 3913.480214] find_first_bit: 4353244 cycles, 16484 iterations
 [ 3913.480216] Start testing find_next_and_bit() with random-filled
 bitmap
 [ 3913.481074] find_next_and_bit: 89604 cycles, 8216 iterations
 [ 3913.481075] Start testing find_bit() with sparse bitmap
 [ 3913.481078] find_next_bit: 2536 cycles, 66 iterations
 [ 3913.481252] find_next_zero_bit: 344404 cycles, 32703 iterations
 [ 3913.481255] find_last_bit: 2006 cycles, 66 iterations
 [ 3913.481265] find_first_bit: 17488 cycles, 66 iterations
 [ 3913.481266] Start testing find_next_and_bit() with sparse bitmap
 [ 3913.481272] find_next_and_bit: 764 cycles, 1 iterations

[3] test_find_next_bit, arm (v7 odroid XU3).

[  267.206928] Start testing find_bit() with random-filled bitmap
[  267.214752] find_next_bit: 4474 cycles, 16419 iterations
[  267.221850] find_next_zero_bit: 5976 cycles, 16350 iterations
[  267.229294] find_last_bit: 4209 cycles, 16419 iterations
[  267.279131] find_first_bit: 1032991 cycles, 16420 iterations
[  267.286265] Start testing find_next_and_bit() with random-filled
bitmap
[  267.302386] find_next_and_bit: 2290 cycles, 8140 iterations
[  267.309422] Start testing find_bit() with sparse bitmap
[  267.316054] find_next_bit: 191 cycles, 66 iterations
[  267.322726] find_next_zero_bit: 8758 cycles, 32703 iterations
[  267.329803] find_last_bit: 84 cycles, 66 iterations
[  267.336169] find_first_bit: 4118 cycles, 66 iterations
[  267.342627] Start testing find_next_and_bit() with sparse bitmap
[  267.356919] find_next_and_bit: 91 cycles, 1 iterations

[courbet@google.com: v6]
  Link: http://lkml.kernel.org/r/20171129095715.23430-1-courbet@google.com
[geert@linux-m68k.org: m68k/bitops: always include &lt;asm-generic/bitops/find.h&gt;]
  Link: http://lkml.kernel.org/r/1512556816-28627-1-git-send-email-geert@linux-m68k.org
Link: http://lkml.kernel.org/r/20171128131334.23491-1-courbet@google.com
Signed-off-by: Clement Courbet &lt;courbet@google.com&gt;
Signed-off-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Yury Norov &lt;ynorov@caviumnetworks.com&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Alexey Dobriyan &lt;adobriyan@gmail.com&gt;
Cc: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We've measured that we spend ~0.6% of sys cpu time in cpumask_next_and().
It's essentially a joined iteration in search for a non-zero bit, which is
currently implemented as a lookup join (find a nonzero bit on the lhs,
lookup the rhs to see if it's set there).

Implement a direct join (find a nonzero bit on the incrementally built
join).  Also add generic bitmap benchmarks in the new `test_find_bit`
module for new function (see `find_next_and_bit` in [2] and [3] below).

For cpumask_next_and, direct benchmarking shows that it's 1.17x to 14x
faster with a geometric mean of 2.1 on 32 CPUs [1].  No impact on memory
usage.  Note that on Arm, the new pure-C implementation still outperforms
the old one that uses a mix of C and asm (`find_next_bit`) [3].

[1] Approximate benchmark code:

```
  unsigned long src1p[nr_cpumask_longs] = {pattern1};
  unsigned long src2p[nr_cpumask_longs] = {pattern2};
  for (/*a bunch of repetitions*/) {
    for (int n = -1; n &lt;= nr_cpu_ids; ++n) {
      asm volatile("" : "+rm"(src1p)); // prevent any optimization
      asm volatile("" : "+rm"(src2p));
      unsigned long result = cpumask_next_and(n, src1p, src2p);
      asm volatile("" : "+rm"(result));
    }
  }
```

Results:
pattern1    pattern2     time_before/time_after
0x0000ffff  0x0000ffff   1.65
0x0000ffff  0x00005555   2.24
0x0000ffff  0x00001111   2.94
0x0000ffff  0x00000000   14.0
0x00005555  0x0000ffff   1.67
0x00005555  0x00005555   1.71
0x00005555  0x00001111   1.90
0x00005555  0x00000000   6.58
0x00001111  0x0000ffff   1.46
0x00001111  0x00005555   1.49
0x00001111  0x00001111   1.45
0x00001111  0x00000000   3.10
0x00000000  0x0000ffff   1.18
0x00000000  0x00005555   1.18
0x00000000  0x00001111   1.17
0x00000000  0x00000000   1.25
-----------------------------
               geo.mean  2.06

[2] test_find_next_bit, X86 (skylake)

 [ 3913.477422] Start testing find_bit() with random-filled bitmap
 [ 3913.477847] find_next_bit: 160868 cycles, 16484 iterations
 [ 3913.477933] find_next_zero_bit: 169542 cycles, 16285 iterations
 [ 3913.478036] find_last_bit: 201638 cycles, 16483 iterations
 [ 3913.480214] find_first_bit: 4353244 cycles, 16484 iterations
 [ 3913.480216] Start testing find_next_and_bit() with random-filled
 bitmap
 [ 3913.481074] find_next_and_bit: 89604 cycles, 8216 iterations
 [ 3913.481075] Start testing find_bit() with sparse bitmap
 [ 3913.481078] find_next_bit: 2536 cycles, 66 iterations
 [ 3913.481252] find_next_zero_bit: 344404 cycles, 32703 iterations
 [ 3913.481255] find_last_bit: 2006 cycles, 66 iterations
 [ 3913.481265] find_first_bit: 17488 cycles, 66 iterations
 [ 3913.481266] Start testing find_next_and_bit() with sparse bitmap
 [ 3913.481272] find_next_and_bit: 764 cycles, 1 iterations

[3] test_find_next_bit, arm (v7 odroid XU3).

[  267.206928] Start testing find_bit() with random-filled bitmap
[  267.214752] find_next_bit: 4474 cycles, 16419 iterations
[  267.221850] find_next_zero_bit: 5976 cycles, 16350 iterations
[  267.229294] find_last_bit: 4209 cycles, 16419 iterations
[  267.279131] find_first_bit: 1032991 cycles, 16420 iterations
[  267.286265] Start testing find_next_and_bit() with random-filled
bitmap
[  267.302386] find_next_and_bit: 2290 cycles, 8140 iterations
[  267.309422] Start testing find_bit() with sparse bitmap
[  267.316054] find_next_bit: 191 cycles, 66 iterations
[  267.322726] find_next_zero_bit: 8758 cycles, 32703 iterations
[  267.329803] find_last_bit: 84 cycles, 66 iterations
[  267.336169] find_first_bit: 4118 cycles, 66 iterations
[  267.342627] Start testing find_next_and_bit() with sparse bitmap
[  267.356919] find_next_and_bit: 91 cycles, 1 iterations

[courbet@google.com: v6]
  Link: http://lkml.kernel.org/r/20171129095715.23430-1-courbet@google.com
[geert@linux-m68k.org: m68k/bitops: always include &lt;asm-generic/bitops/find.h&gt;]
  Link: http://lkml.kernel.org/r/1512556816-28627-1-git-send-email-geert@linux-m68k.org
Link: http://lkml.kernel.org/r/20171128131334.23491-1-courbet@google.com
Signed-off-by: Clement Courbet &lt;courbet@google.com&gt;
Signed-off-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Yury Norov &lt;ynorov@caviumnetworks.com&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: Alexey Dobriyan &lt;adobriyan@gmail.com&gt;
Cc: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm64: KVM: Report SMCCC_ARCH_WORKAROUND_1 BP hardening support</title>
<updated>2018-02-06T22:54:05+00:00</updated>
<author>
<name>Marc Zyngier</name>
<email>marc.zyngier@arm.com</email>
</author>
<published>2018-02-06T17:56:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6167ec5c9145cdf493722dfd80a5d48bafc4a18a'/>
<id>6167ec5c9145cdf493722dfd80a5d48bafc4a18a</id>
<content type='text'>
A new feature of SMCCC 1.1 is that it offers firmware-based CPU
workarounds. In particular, SMCCC_ARCH_WORKAROUND_1 provides
BP hardening for CVE-2017-5715.

If the host has some mitigation for this issue, report that
we deal with it using SMCCC_ARCH_WORKAROUND_1, as we apply the
host workaround on every guest exit.

Tested-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Reviewed-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
A new feature of SMCCC 1.1 is that it offers firmware-based CPU
workarounds. In particular, SMCCC_ARCH_WORKAROUND_1 provides
BP hardening for CVE-2017-5715.

If the host has some mitigation for this issue, report that
we deal with it using SMCCC_ARCH_WORKAROUND_1, as we apply the
host workaround on every guest exit.

Tested-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Reviewed-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm/arm64: KVM: Advertise SMCCC v1.1</title>
<updated>2018-02-06T22:54:01+00:00</updated>
<author>
<name>Marc Zyngier</name>
<email>marc.zyngier@arm.com</email>
</author>
<published>2018-02-06T17:56:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=09e6be12effdb33bf7210c8867bbd213b66a499e'/>
<id>09e6be12effdb33bf7210c8867bbd213b66a499e</id>
<content type='text'>
The new SMC Calling Convention (v1.1) allows for a reduced overhead
when calling into the firmware, and provides a new feature discovery
mechanism.

Make it visible to KVM guests.

Tested-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Reviewed-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The new SMC Calling Convention (v1.1) allows for a reduced overhead
when calling into the firmware, and provides a new feature discovery
mechanism.

Make it visible to KVM guests.

Tested-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Reviewed-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm/arm64: KVM: Consolidate the PSCI include files</title>
<updated>2018-02-06T22:53:54+00:00</updated>
<author>
<name>Marc Zyngier</name>
<email>marc.zyngier@arm.com</email>
</author>
<published>2018-02-06T17:56:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1a2fb94e6a771ff94f4afa22497a4695187b820c'/>
<id>1a2fb94e6a771ff94f4afa22497a4695187b820c</id>
<content type='text'>
As we're about to update the PSCI support, and because I'm lazy,
let's move the PSCI include file to include/kvm so that both
ARM architectures can find it.

Acked-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Tested-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
As we're about to update the PSCI support, and because I'm lazy,
let's move the PSCI include file to include/kvm so that both
ARM architectures can find it.

Acked-by: Christoffer Dall &lt;christoffer.dall@linaro.org&gt;
Tested-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>arm: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls</title>
<updated>2018-02-06T22:53:50+00:00</updated>
<author>
<name>Marc Zyngier</name>
<email>marc.zyngier@arm.com</email>
</author>
<published>2018-02-06T17:56:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=20e8175d246e9f9deb377f2784b3e7dfb2ad3e86'/>
<id>20e8175d246e9f9deb377f2784b3e7dfb2ad3e86</id>
<content type='text'>
KVM doesn't follow the SMCCC when it comes to unimplemented calls,
and inject an UNDEF instead of returning an error. Since firmware
calls are now used for security mitigation, they are becoming more
common, and the undef is counter productive.

Instead, let's follow the SMCCC which states that -1 must be returned
to the caller when getting an unknown function number.

Cc: &lt;stable@vger.kernel.org&gt;
Tested-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
KVM doesn't follow the SMCCC when it comes to unimplemented calls,
and inject an UNDEF instead of returning an error. Since firmware
calls are now used for security mitigation, they are becoming more
common, and the undef is counter productive.

Instead, let's follow the SMCCC which states that -1 must be returned
to the caller when getting an unknown function number.

Cc: &lt;stable@vger.kernel.org&gt;
Tested-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Signed-off-by: Marc Zyngier &lt;marc.zyngier@arm.com&gt;
Signed-off-by: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'media/v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media</title>
<updated>2018-02-06T19:27:48+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-02-06T19:27:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=68c5735eaa5e680e701c9a2d1e3c7880bdf5ab66'/>
<id>68c5735eaa5e680e701c9a2d1e3c7880bdf5ab66</id>
<content type='text'>
Pull media updates from Mauro Carvalho Chehab:

 - videobuf2 was moved to a media/common dir, as it is now used by the
   DVB subsystem too

 - Digital TV core memory mapped support interface

 - new sensor driver: ov7740

 - several improvements at ddbridge driver

 - new V4L2 driver: IPU3 CIO2 CSI-2 receiver unit, found on some Intel
   SoCs

 - new tuner driver: tda18250

 - finally got rid of all LIRC staging drivers

 - as we don't have old lirc drivers anymore, restruct the lirc device
   code

 - add support for UVC metadata

 - add a new staging driver for NVIDIA Tegra Video Decoder Engine

 - DVB kAPI headers moved to include/media

 - synchronize the kAPI and uAPI for the DVB subsystem, removing the gap
   for non-legacy APIs

 - reduce the kAPI gap for V4L2

 - lots of other driver enhancements, cleanups, etc.

* tag 'media/v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (407 commits)
  media: v4l2-compat-ioctl32.c: make ctrl_is_pointer work for subdevs
  media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic
  media: v4l2-compat-ioctl32.c: don't copy back the result for certain errors
  media: v4l2-compat-ioctl32.c: drop pr_info for unknown buffer type
  media: v4l2-compat-ioctl32.c: copy clip list in put_v4l2_window32
  media: v4l2-compat-ioctl32.c: fix ctrl_is_pointer
  media: v4l2-compat-ioctl32.c: copy m.userptr in put_v4l2_plane32
  media: v4l2-compat-ioctl32.c: avoid sizeof(type)
  media: v4l2-compat-ioctl32.c: move 'helper' functions to __get/put_v4l2_format32
  media: v4l2-compat-ioctl32.c: fix the indentation
  media: v4l2-compat-ioctl32.c: add missing VIDIOC_PREPARE_BUF
  media: v4l2-ioctl.c: don't copy back the result for -ENOTTY
  media: v4l2-ioctl.c: use check_fmt for enum/g/s/try_fmt
  media: vivid: fix module load error when enabling fb and no_error_inj=1
  media: dvb_demux: improve debug messages
  media: dvb_demux: Better handle discontinuity errors
  media: cxusb, dib0700: ignore XC2028_I2C_FLUSH
  media: ts2020: avoid integer overflows on 32 bit machines
  media: i2c: ov7740: use gpio/consumer.h instead of gpio.h
  media: entity: Add a nop variant of media_entity_cleanup
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull media updates from Mauro Carvalho Chehab:

 - videobuf2 was moved to a media/common dir, as it is now used by the
   DVB subsystem too

 - Digital TV core memory mapped support interface

 - new sensor driver: ov7740

 - several improvements at ddbridge driver

 - new V4L2 driver: IPU3 CIO2 CSI-2 receiver unit, found on some Intel
   SoCs

 - new tuner driver: tda18250

 - finally got rid of all LIRC staging drivers

 - as we don't have old lirc drivers anymore, restruct the lirc device
   code

 - add support for UVC metadata

 - add a new staging driver for NVIDIA Tegra Video Decoder Engine

 - DVB kAPI headers moved to include/media

 - synchronize the kAPI and uAPI for the DVB subsystem, removing the gap
   for non-legacy APIs

 - reduce the kAPI gap for V4L2

 - lots of other driver enhancements, cleanups, etc.

* tag 'media/v4.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (407 commits)
  media: v4l2-compat-ioctl32.c: make ctrl_is_pointer work for subdevs
  media: v4l2-compat-ioctl32.c: refactor compat ioctl32 logic
  media: v4l2-compat-ioctl32.c: don't copy back the result for certain errors
  media: v4l2-compat-ioctl32.c: drop pr_info for unknown buffer type
  media: v4l2-compat-ioctl32.c: copy clip list in put_v4l2_window32
  media: v4l2-compat-ioctl32.c: fix ctrl_is_pointer
  media: v4l2-compat-ioctl32.c: copy m.userptr in put_v4l2_plane32
  media: v4l2-compat-ioctl32.c: avoid sizeof(type)
  media: v4l2-compat-ioctl32.c: move 'helper' functions to __get/put_v4l2_format32
  media: v4l2-compat-ioctl32.c: fix the indentation
  media: v4l2-compat-ioctl32.c: add missing VIDIOC_PREPARE_BUF
  media: v4l2-ioctl.c: don't copy back the result for -ENOTTY
  media: v4l2-ioctl.c: use check_fmt for enum/g/s/try_fmt
  media: vivid: fix module load error when enabling fb and no_error_inj=1
  media: dvb_demux: improve debug messages
  media: dvb_demux: Better handle discontinuity errors
  media: cxusb, dib0700: ignore XC2028_I2C_FLUSH
  media: ts2020: avoid integer overflows on 32 bit machines
  media: i2c: ov7740: use gpio/consumer.h instead of gpio.h
  media: entity: Add a nop variant of media_entity_cleanup
  ...
</pre>
</div>
</content>
</entry>
</feed>
