<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-dev/tools/arch, branch linus/master</title>
<subtitle>Linux kernel development work - see feature branches</subtitle>
<id>https://git.zx2c4.com/linux-dev/atom/tools/arch?h=linus%2Fmaster</id>
<link rel='self' href='https://git.zx2c4.com/linux-dev/atom/tools/arch?h=linus%2Fmaster'/>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/'/>
<updated>2022-06-19T14:23:04Z</updated>
<entry>
<title>tools headers arm64: Sync arm64's cputype.h with the kernel sources</title>
<updated>2022-06-19T14:23:04Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2022-04-09T14:48:15Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=37402d5d061ba914a12d16ee8dda6d6964b4819d'/>
<id>urn:sha1:37402d5d061ba914a12d16ee8dda6d6964b4819d</id>
<content type='text'>
To get the changes in:

  cae889302ebf5a9b ("KVM: arm64: vgic-v3: List M1 Pro/Max as requiring the SEIS workaround")

That addresses this perf build warning:

  Warning: Kernel ABI header at 'tools/arch/arm64/include/asm/cputype.h' differs from latest version at 'arch/arm64/include/asm/cputype.h'
  diff -u tools/arch/arm64/include/asm/cputype.h arch/arm64/include/asm/cputype.h

Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Link: https://lore.kernel.org/lkml/Yq8w7p4omYKNwOij@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>tools headers UAPI: Sync x86's asm/kvm.h with the kernel sources</title>
<updated>2022-06-19T14:22:59Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2021-09-10T14:46:54Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=2e323f360a7b635a4df6faea616b80c188e68991'/>
<id>urn:sha1:2e323f360a7b635a4df6faea616b80c188e68991</id>
<content type='text'>
To pick the changes in:

  f1a9761fbb00639c ("KVM: x86: Allow userspace to opt out of hypercall patching")

That just rebuilds kvm-stat.c on x86, no change in functionality.

This silences these perf build warning:

  Warning: Kernel ABI header at 'tools/arch/x86/include/uapi/asm/kvm.h' differs from latest version at 'arch/x86/include/uapi/asm/kvm.h'
  diff -u tools/arch/x86/include/uapi/asm/kvm.h arch/x86/include/uapi/asm/kvm.h

Cc: Oliver Upton &lt;oupton@google.com&gt;
Cc: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Link: https://lore.kernel.org/lkml/Yq8qgiMwRcl9ds+f@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'x86-bugs-2022-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2022-06-14T14:43:15Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-06-14T14:43:15Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=8e8afafb0b5571b7cb10b529dc60cadb7241bed4'/>
<id>urn:sha1:8e8afafb0b5571b7cb10b529dc60cadb7241bed4</id>
<content type='text'>
Pull x86 MMIO stale data fixes from Thomas Gleixner:
 "Yet another hw vulnerability with a software mitigation: Processor
  MMIO Stale Data.

  They are a class of MMIO-related weaknesses which can expose stale
  data by propagating it into core fill buffers. Data which can then be
  leaked using the usual speculative execution methods.

  Mitigations include this set along with microcode updates and are
  similar to MDS and TAA vulnerabilities: VERW now clears those buffers
  too"

* tag 'x86-bugs-2022-06-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/speculation/mmio: Print SMT warning
  KVM: x86/speculation: Disable Fill buffer clear within guests
  x86/speculation/mmio: Reuse SRBDS mitigation for SBDS
  x86/speculation/srbds: Update SRBDS mitigation selection
  x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data
  x86/speculation/mmio: Enable CPU Fill buffer clearing on idle
  x86/bugs: Group MDS, TAA &amp; Processor MMIO Stale Data mitigations
  x86/speculation/mmio: Add mitigation for Processor MMIO Stale Data
  x86/speculation: Add a common function for MD_CLEAR mitigation update
  x86/speculation/mmio: Enumerate Processor MMIO Stale Data bug
  Documentation: Add documentation for Processor MMIO Stale Data
</content>
</entry>
<entry>
<title>Merge tag 'perf-tools-for-v5.19-2022-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux</title>
<updated>2022-05-29T17:10:15Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-05-29T17:10:15Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=09f73a1ab8207481d1d6bd91ab7d0125c6722005'/>
<id>urn:sha1:09f73a1ab8207481d1d6bd91ab7d0125c6722005</id>
<content type='text'>
Pull more perf tools updates from Arnaldo Carvalho de Melo:

 - Add BPF based off-CPU profiling

 - Improvements for system wide recording, specially for Intel PT

 - Improve DWARF unwinding on arm64

 - Support Arm CoreSight trace data disassembly in 'perf script' python

 - Fix build with new libbpf version, related to supporting older
   versions of distro released libbpf packages

 - Fix event syntax error caused by ExtSel in the JSON events infra

 - Use stdio interface if slang is not supported in 'perf c2c'

 - Add 'perf test' checking for perf stat CSV output

 - Sync the msr-index.h copy with the kernel sources

* tag 'perf-tools-for-v5.19-2022-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (38 commits)
  tools arch x86: Sync the msr-index.h copy with the kernel sources
  perf scripts python: Support Arm CoreSight trace data disassembly
  perf scripting python: Expose dso and map information
  perf jevents: Fix event syntax error caused by ExtSel
  perf tools arm64: Add support for VG register
  perf unwind arm64: Decouple Libunwind register names from Perf
  perf unwind: Use dynamic register set for DWARF unwind
  perf tools arm64: Copy perf_regs.h from the kernel
  perf unwind arm64: Use perf's copy of kernel headers
  perf c2c: Use stdio interface if slang is not supported
  perf test: Add a basic offcpu profiling test
  perf record: Add cgroup support for off-cpu profiling
  perf record: Handle argument change in sched_switch
  perf record: Implement basic filtering for off-cpu
  perf record: Enable off-cpu analysis with BPF
  perf report: Do not extend sample type of bpf-output event
  perf test: Add checking for perf stat CSV output.
  perf tools: Allow system-wide events to keep their own threads
  perf tools: Allow system-wide events to keep their own CPUs
  libperf evsel: Add comments for booleans
  ...
</content>
</entry>
<entry>
<title>tools arch x86: Sync the msr-index.h copy with the kernel sources</title>
<updated>2022-05-27T16:22:14Z</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2020-08-07T11:45:47Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=9dde6cadb92b5670b23b97ec53091df0530ec38b'/>
<id>urn:sha1:9dde6cadb92b5670b23b97ec53091df0530ec38b</id>
<content type='text'>
To pick up the changes in:

  db1af12929c99d15 ("x86/msr-index: Define INTEGRITY_CAPABILITIES MSR")
  089be16d5992dd0b ("x86/msr: Add PerfCntrGlobal* registers")
  f52ba93190457aa2 ("tools/power turbostat: Add Power Limit4 support")

Addressing these tools/perf build warnings:

    diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h
    Warning: Kernel ABI header at 'tools/arch/x86/include/asm/msr-index.h' differs from latest version at 'arch/x86/include/asm/msr-index.h'

That makes the beautification scripts to pick some new entries:

  $ tools/perf/trace/beauty/tracepoints/x86_msr.sh &gt; before
  $ cp arch/x86/include/asm/msr-index.h tools/arch/x86/include/asm/msr-index.h
  $ tools/perf/trace/beauty/tracepoints/x86_msr.sh &gt; after
  $ diff -u before after
  --- before	2022-05-26 12:50:01.228612839 -0300
  +++ after	2022-05-26 12:50:07.699776166 -0300
  @@ -116,6 +116,7 @@
   	[0x0000026f] = "MTRRfix4K_F8000",
   	[0x00000277] = "IA32_CR_PAT",
   	[0x00000280] = "IA32_MC0_CTL2",
  +	[0x000002d9] = "INTEGRITY_CAPS",
   	[0x000002ff] = "MTRRdefType",
   	[0x00000309] = "CORE_PERF_FIXED_CTR0",
   	[0x0000030a] = "CORE_PERF_FIXED_CTR1",
  @@ -176,6 +177,7 @@
   	[0x00000586] = "IA32_RTIT_ADDR3_A",
   	[0x00000587] = "IA32_RTIT_ADDR3_B",
   	[0x00000600] = "IA32_DS_AREA",
  +	[0x00000601] = "VR_CURRENT_CONFIG",
   	[0x00000606] = "RAPL_POWER_UNIT",
   	[0x0000060a] = "PKGC3_IRTL",
   	[0x0000060b] = "PKGC6_IRTL",
  @@ -260,6 +262,10 @@
   	[0xc0000102 - x86_64_specific_MSRs_offset] = "KERNEL_GS_BASE",
   	[0xc0000103 - x86_64_specific_MSRs_offset] = "TSC_AUX",
   	[0xc0000104 - x86_64_specific_MSRs_offset] = "AMD64_TSC_RATIO",
  +	[0xc000010f - x86_64_specific_MSRs_offset] = "AMD_DBG_EXTN_CFG",
  +	[0xc0000300 - x86_64_specific_MSRs_offset] = "AMD64_PERF_CNTR_GLOBAL_STATUS",
  +	[0xc0000301 - x86_64_specific_MSRs_offset] = "AMD64_PERF_CNTR_GLOBAL_CTL",
  +	[0xc0000302 - x86_64_specific_MSRs_offset] = "AMD64_PERF_CNTR_GLOBAL_STATUS_CLR",
   };

   #define x86_AMD_V_KVM_MSRs_offset 0xc0010000
  @@ -318,4 +324,5 @@
   	[0xc00102b4 - x86_AMD_V_KVM_MSRs_offset] = "AMD_CPPC_STATUS",
   	[0xc00102f0 - x86_AMD_V_KVM_MSRs_offset] = "AMD_PPIN_CTL",
   	[0xc00102f1 - x86_AMD_V_KVM_MSRs_offset] = "AMD_PPIN",
  +	[0xc0010300 - x86_AMD_V_KVM_MSRs_offset] = "AMD_SAMP_BR_FROM",
   };
  $

Now one can trace systemwide asking to see backtraces to where those
MSRs are being read/written, see this example with a previous update:

  # perf trace -e msr:*_msr/max-stack=32/ --filter="msr&gt;=IA32_U_CET &amp;&amp; msr&lt;=IA32_INT_SSP_TAB"
  ^C#

If we use -v (verbose mode) we can see what it does behind the scenes:

  # perf trace -v -e msr:*_msr/max-stack=32/ --filter="msr&gt;=IA32_U_CET &amp;&amp; msr&lt;=IA32_INT_SSP_TAB"
  Using CPUID AuthenticAMD-25-21-0
  0x6a0
  0x6a8
  New filter for msr:read_msr: (msr&gt;=0x6a0 &amp;&amp; msr&lt;=0x6a8) &amp;&amp; (common_pid != 597499 &amp;&amp; common_pid != 3313)
  0x6a0
  0x6a8
  New filter for msr:write_msr: (msr&gt;=0x6a0 &amp;&amp; msr&lt;=0x6a8) &amp;&amp; (common_pid != 597499 &amp;&amp; common_pid != 3313)
  mmap size 528384B
  ^C#

Example with a frequent msr:

  # perf trace -v -e msr:*_msr/max-stack=32/ --filter="msr==IA32_SPEC_CTRL" --max-events 2
  Using CPUID AuthenticAMD-25-21-0
  0x48
  New filter for msr:read_msr: (msr==0x48) &amp;&amp; (common_pid != 2612129 &amp;&amp; common_pid != 3841)
  0x48
  New filter for msr:write_msr: (msr==0x48) &amp;&amp; (common_pid != 2612129 &amp;&amp; common_pid != 3841)
  mmap size 528384B
  Looking at the vmlinux_path (8 entries long)
  symsrc__init: build id mismatch for vmlinux.
  Using /proc/kcore for kernel data
  Using /proc/kallsyms for symbols
     0.000 Timer/2525383 msr:write_msr(msr: IA32_SPEC_CTRL, val: 6)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       __switch_to_xtra ([kernel.kallsyms])
                                       __switch_to ([kernel.kallsyms])
                                       __schedule ([kernel.kallsyms])
                                       schedule ([kernel.kallsyms])
                                       futex_wait_queue_me ([kernel.kallsyms])
                                       futex_wait ([kernel.kallsyms])
                                       do_futex ([kernel.kallsyms])
                                       __x64_sys_futex ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
                                       __futex_abstimed_wait_common64 (/usr/lib64/libpthread-2.33.so)
     0.030 :0/0 msr:write_msr(msr: IA32_SPEC_CTRL, val: 2)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       __switch_to_xtra ([kernel.kallsyms])
                                       __switch_to ([kernel.kallsyms])
                                       __schedule ([kernel.kallsyms])
                                       schedule_idle ([kernel.kallsyms])
                                       do_idle ([kernel.kallsyms])
                                       cpu_startup_entry ([kernel.kallsyms])
                                       secondary_startup_64_no_verify ([kernel.kallsyms])
  #

Cc: Adrian Hunter &lt;adrian.hunter@intel.com&gt;
Cc: Hans de Goede &lt;hdegoede@redhat.com&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: Len Brown &lt;len.brown@intel.com&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Sandipan Das &lt;sandipan.das@amd.com&gt;
Cc: Sumeet Pawnikar &lt;sumeet.r.pawnikar@intel.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Link: https://lore.kernel.org/lkml/Yo+i%252Fj5+UtE9dcix@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'asm-generic-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic</title>
<updated>2022-05-26T17:50:30Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-05-26T17:50:30Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=16477cdfefdb494235a675cc80563d736991d833'/>
<id>urn:sha1:16477cdfefdb494235a675cc80563d736991d833</id>
<content type='text'>
Pull asm-generic updates from Arnd Bergmann:
 "The asm-generic tree contains three separate changes for linux-5.19:

   - The h8300 architecture is retired after it has been effectively
     unmaintained for a number of years. This is the last architecture
     we supported that has no MMU implementation, but there are still a
     few architectures (arm, m68k, riscv, sh and xtensa) that support
     CPUs with and without an MMU.

   - A series to add a generic ticket spinlock that can be shared by
     most architectures with a working cmpxchg or ll/sc type atomic,
     including the conversion of riscv, csky and openrisc. This series
     is also a prerequisite for the loongarch64 architecture port that
     will come as a separate pull request.

   - A cleanup of some exported uapi header files to ensure they can be
     included from user space without relying on other kernel headers"

* tag 'asm-generic-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  h8300: remove stale bindings and symlink
  sparc: add asm/stat.h to UAPI compile-test coverage
  powerpc: add asm/stat.h to UAPI compile-test coverage
  mips: add asm/stat.h to UAPI compile-test coverage
  riscv: add linux/bpf_perf_event.h to UAPI compile-test coverage
  kbuild: prevent exported headers from including &lt;stdlib.h&gt;, &lt;stdbool.h&gt;
  agpgart.h: do not include &lt;stdlib.h&gt; from exported header
  csky: Move to generic ticket-spinlock
  RISC-V: Move to queued RW locks
  RISC-V: Move to generic spinlocks
  openrisc: Move to ticket-spinlock
  asm-generic: qrwlock: Document the spinlock fairness requirements
  asm-generic: qspinlock: Indicate the use of mixed-size atomics
  asm-generic: ticket-lock: New generic ticket-based spinlock
  remove the h8300 architecture
</content>
</entry>
<entry>
<title>perf tools arm64: Copy perf_regs.h from the kernel</title>
<updated>2022-05-26T15:36:58Z</updated>
<author>
<name>James Clark</name>
<email>james.clark@arm.com</email>
</author>
<published>2022-05-25T15:41:11Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=f450f11b2d3f48e7eb0c9ca34ee5c873521e0b7b'/>
<id>urn:sha1:f450f11b2d3f48e7eb0c9ca34ee5c873521e0b7b</id>
<content type='text'>
Get the updated header for the newly added VG register.

Reviewed-by: Leo Yan &lt;leo.yan@linaro.org&gt;
Signed-off-by: James Clark &lt;james.clark@arm.com&gt;
Cc: &lt;broonie@kernel.org&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: German Gomez &lt;german.gomez@arm.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@kernel.org&gt;
Cc: John Garry &lt;john.garry@huawei.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Cc: Mike Leach &lt;mike.leach@linaro.org&gt;
Cc: Namhyung Kim &lt;namhyung@kernel.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20220525154114.718321-3-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'perf-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2022-05-24T17:59:38Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-05-24T17:59:38Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=cfeb2522c3777923c2bd24772b914195dc93c86b'/>
<id>urn:sha1:cfeb2522c3777923c2bd24772b914195dc93c86b</id>
<content type='text'>
Pull perf events updates from Ingo Molnar:
 "Platform PMU changes:

   - x86/intel:
      - Add new Intel Alder Lake and Raptor Lake support

   - x86/amd:
      - AMD Zen4 IBS extensions support
      - Add AMD PerfMonV2 support
      - Add AMD Fam19h Branch Sampling support

  Generic changes:

   - signal: Deliver SIGTRAP on perf event asynchronously if blocked

     Perf instrumentation can be driven via SIGTRAP, but this causes a
     problem when SIGTRAP is blocked by a task &amp; terminate the task.

     Allow user-space to request these signals asynchronously (after
     they get unblocked) &amp; also give the information to the signal
     handler when this happens:

       "To give user space the ability to clearly distinguish
        synchronous from asynchronous signals, introduce
        siginfo_t::si_perf_flags and TRAP_PERF_FLAG_ASYNC (opted for
        flags in case more binary information is required in future).

        The resolution to the problem is then to (a) no longer force the
        signal (avoiding the terminations), but (b) tell user space via
        si_perf_flags if the signal was synchronous or not, so that such
        signals can be handled differently (e.g. let user space decide
        to ignore or consider the data imprecise). "

   - Unify/standardize the /sys/devices/cpu/events/* output format.

   - Misc fixes &amp; cleanups"

* tag 'perf-core-2022-05-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
  perf/x86/amd/core: Fix reloading events for SVM
  perf/x86/amd: Run AMD BRS code only on supported hw
  perf/x86/amd: Fix AMD BRS period adjustment
  perf/x86/amd: Remove unused variable 'hwc'
  perf/ibs: Fix comment
  perf/amd/ibs: Advertise zen4_ibs_extensions as pmu capability attribute
  perf/amd/ibs: Add support for L3 miss filtering
  perf/amd/ibs: Use -&gt;is_visible callback for dynamic attributes
  perf/amd/ibs: Cascade pmu init functions' return value
  perf/x86/uncore: Add new Alder Lake and Raptor Lake support
  perf/x86/uncore: Clean up uncore_pci_ids[]
  perf/x86/cstate: Add new Alder Lake and Raptor Lake support
  perf/x86/msr: Add new Alder Lake and Raptor Lake support
  perf/x86: Add new Alder Lake and Raptor Lake support
  perf/amd/ibs: Use interrupt regs ip for stack unwinding
  perf/x86/amd/core: Add PerfMonV2 overflow handling
  perf/x86/amd/core: Add PerfMonV2 counter control
  perf/x86/amd/core: Detect available counters
  perf/x86/amd/core: Detect PerfMonV2 support
  x86/msr: Add PerfCntrGlobal* registers
  ...
</content>
</entry>
<entry>
<title>Merge tag 'x86_cpu_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2022-05-24T01:01:31Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-05-24T01:01:31Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=c5a3d3c01e90e74166f95eec9db6fcc3ba72a9d6'/>
<id>urn:sha1:c5a3d3c01e90e74166f95eec9db6fcc3ba72a9d6</id>
<content type='text'>
Pull x86 CPU feature updates from Borislav Petkov:

 - Remove a bunch of chicken bit options to turn off CPU features which
   are not really needed anymore

 - Misc fixes and cleanups

* tag 'x86_cpu_for_v5.19_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/speculation: Add missing prototype for unpriv_ebpf_notify()
  x86/pm: Fix false positive kmemleak report in msr_build_context()
  x86/speculation/srbds: Do not try to turn mitigation off when not supported
  x86/cpu: Remove "noclflush"
  x86/cpu: Remove "noexec"
  x86/cpu: Remove "nosmep"
  x86/cpu: Remove CONFIG_X86_SMAP and "nosmap"
  x86/cpu: Remove "nosep"
  x86/cpu: Allow feature bit names from /proc/cpuinfo in clearcpuid=
</content>
</entry>
<entry>
<title>KVM: x86/speculation: Disable Fill buffer clear within guests</title>
<updated>2022-05-21T10:41:35Z</updated>
<author>
<name>Pawan Gupta</name>
<email>pawan.kumar.gupta@linux.intel.com</email>
</author>
<published>2022-05-20T03:35:15Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=027bbb884be006b05d9c577d6401686053aa789e'/>
<id>urn:sha1:027bbb884be006b05d9c577d6401686053aa789e</id>
<content type='text'>
The enumeration of MD_CLEAR in CPUID(EAX=7,ECX=0).EDX{bit 10} is not an
accurate indicator on all CPUs of whether the VERW instruction will
overwrite fill buffers. FB_CLEAR enumeration in
IA32_ARCH_CAPABILITIES{bit 17} covers the case of CPUs that are not
vulnerable to MDS/TAA, indicating that microcode does overwrite fill
buffers.

Guests running in VMM environments may not be aware of all the
capabilities/vulnerabilities of the host CPU. Specifically, a guest may
apply MDS/TAA mitigations when a virtual CPU is enumerated as vulnerable
to MDS/TAA even when the physical CPU is not. On CPUs that enumerate
FB_CLEAR_CTRL the VMM may set FB_CLEAR_DIS to skip overwriting of fill
buffers by the VERW instruction. This is done by setting FB_CLEAR_DIS
during VMENTER and resetting on VMEXIT. For guests that enumerate
FB_CLEAR (explicitly asking for fill buffer clear capability) the VMM
will not use FB_CLEAR_DIS.

Irrespective of guest state, host overwrites CPU buffers before VMENTER
to protect itself from an MMIO capable guest, as part of mitigation for
MMIO Stale Data vulnerabilities.

Signed-off-by: Pawan Gupta &lt;pawan.kumar.gupta@linux.intel.com&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
</content>
</entry>
</feed>
