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  1. Nov 26, 2018
  2. Oct 09, 2018
    • Suraj Jitindar Singh's avatar
      KVM: PPC: Book3S HV: Sanitise hv_regs on nested guest entry · 73937deb
      Suraj Jitindar Singh authored
      
      restore_hv_regs() is used to copy the hv_regs L1 wants to set to run the
      nested (L2) guest into the vcpu structure. We need to sanitise these
      values to ensure we don't let the L1 guest hypervisor do things we don't
      want it to.
      
      We don't let data address watchpoints or completed instruction address
      breakpoints be set to match in hypervisor state.
      
      We also don't let L1 enable features in the hypervisor facility status
      and control register (HFSCR) for L2 which we have disabled for L1. That
      is L2 will get the subset of features which the L0 hypervisor has
      enabled for L1 and the features L1 wants to enable for L2. This could
      mean we give L1 a hypervisor facility unavailable interrupt for a
      facility it thinks it has enabled, however it shouldn't have enabled a
      facility it itself doesn't have for the L2 guest.
      
      We sanitise the registers when copying in the L2 hv_regs. We don't need
      to sanitise when copying back the L1 hv_regs since these shouldn't be
      able to contain invalid values as they're just what was copied out.
      
      Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      Signed-off-by: default avatarSuraj Jitindar Singh <sjitindarsingh@gmail.com>
      Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      73937deb
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Handle hypervisor instruction faults better · 32eb150a
      Paul Mackerras authored
      
      Currently the code for handling hypervisor instruction page faults
      passes 0 for the flags indicating the type of fault, which is OK in
      the usual case that the page is not mapped in the partition-scoped
      page tables.  However, there are other causes for hypervisor
      instruction page faults, such as not being to update a reference
      (R) or change (C) bit.  The cause is indicated in bits in HSRR1,
      including a bit which indicates that the fault is due to not being
      able to write to a page (for example to update an R or C bit).
      Not handling these other kinds of faults correctly can lead to a
      loop of continual faults without forward progress in the guest.
      
      In order to handle these faults better, this patch constructs a
      "DSISR-like" value from the bits which DSISR and SRR1 (for a HISI)
      have in common, and passes it to kvmppc_book3s_hv_page_fault() so
      that it knows what caused the fault.
      
      Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
      Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      32eb150a
  3. Oct 03, 2018
    • Breno Leitao's avatar
      powerpc/tm: Remove msr_tm_active() · 5c784c84
      Breno Leitao authored
      
      Currently msr_tm_active() is a wrapper around MSR_TM_ACTIVE() if
      CONFIG_PPC_TRANSACTIONAL_MEM is set, or it is just a function that
      returns false if CONFIG_PPC_TRANSACTIONAL_MEM is not set.
      
      This function is not necessary, since MSR_TM_ACTIVE() just do the same and
      could be used, removing the dualism and simplifying the code.
      
      This patchset remove every instance of msr_tm_active() and replaced it
      by MSR_TM_ACTIVE().
      
      Signed-off-by: default avatarBreno Leitao <leitao@debian.org>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      5c784c84
  4. Jul 30, 2018
  5. Jul 18, 2018
  6. May 24, 2018
  7. May 17, 2018
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Set RWMR on POWER8 so PURR/SPURR count correctly · 7aa15842
      Paul Mackerras authored
      
      Although Linux doesn't use PURR and SPURR ((Scaled) Processor
      Utilization of Resources Register), other OSes depend on them.
      On POWER8 they count at a rate depending on whether the VCPU is
      idle or running, the activity of the VCPU, and the value in the
      RWMR (Region-Weighting Mode Register).  Hardware expects the
      hypervisor to update the RWMR when a core is dispatched to reflect
      the number of online VCPUs in the vcore.
      
      This adds code to maintain a count in the vcore struct indicating
      how many VCPUs are online.  In kvmppc_run_core we use that count
      to set the RWMR register on POWER8.  If the core is split because
      of a static or dynamic micro-threading mode, we use the value for
      8 threads.  The RWMR value is not relevant when the host is
      executing because Linux does not use the PURR or SPURR register,
      so we don't bother saving and restoring the host value.
      
      For the sake of old userspace which does not set the KVM_REG_PPC_ONLINE
      register, we set online to 1 if it was 0 at the time of a KVM_RUN
      ioctl.
      
      Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
      7aa15842
  8. Mar 23, 2018
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Work around transactional memory bugs in POWER9 · 4bb3c7a0
      Paul Mackerras authored
      
      POWER9 has hardware bugs relating to transactional memory and thread
      reconfiguration (changes to hardware SMT mode).  Specifically, the core
      does not have enough storage to store a complete checkpoint of all the
      architected state for all four threads.  The DD2.2 version of POWER9
      includes hardware modifications designed to allow hypervisor software
      to implement workarounds for these problems.  This patch implements
      those workarounds in KVM code so that KVM guests see a full, working
      transactional memory implementation.
      
      The problems center around the use of TM suspended state, where the
      CPU has a checkpointed state but execution is not transactional.  The
      workaround is to implement a "fake suspend" state, which looks to the
      guest like suspended state but the CPU does not store a checkpoint.
      In this state, any instruction that would cause a transition to
      transactional state (rfid, rfebb, mtmsrd, tresume) or would use the
      checkpointed state (treclaim) causes a "soft patch" interrupt (vector
      0x1500) to the hypervisor so that it can be emulated.  The trechkpt
      instruction also causes a soft patch interrupt.
      
      On POWER9 DD2.2, we avoid returning to the guest in any state which
      would require a checkpoint to be present.  The trechkpt in the guest
      entry path which would normally create that checkpoint is replaced by
      either a transition to fake suspend state, if the guest is in suspend
      state, or a rollback to the pre-transactional state if the guest is in
      transactional state.  Fake suspend state is indicated by a flag in the
      PACA plus a new bit in the PSSCR.  The new PSSCR bit is write-only and
      reads back as 0.
      
      On exit from the guest, if the guest is in fake suspend state, we still
      do the treclaim instruction as we would in real suspend state, in order
      to get into non-transactional state, but we do not save the resulting
      register state since there was no checkpoint.
      
      Emulation of the instructions that cause a softpatch interrupt is
      handled in two paths.  If the guest is in real suspend mode, we call
      kvmhv_p9_tm_emulation_early() to handle the cases where the guest is
      transitioning to transactional state.  This is called before we do the
      treclaim in the guest exit path; because we haven't done treclaim, we
      can get back to the guest with the transaction still active.  If the
      instruction is a case that kvmhv_p9_tm_emulation_early() doesn't
      handle, or if the guest is in fake suspend state, then we proceed to
      do the complete guest exit path and subsequently call
      kvmhv_p9_tm_emulation() in host context with the MMU on.  This handles
      all the cases including the cases that generate program interrupts
      (illegal instruction or TM Bad Thing) and facility unavailable
      interrupts.
      
      The emulation is reasonably straightforward and is mostly concerned
      with checking for exception conditions and updating the state of
      registers such as MSR and CR0.  The treclaim emulation takes care to
      ensure that the TEXASR register gets updated as if it were the guest
      treclaim instruction that had done failure recording, not the treclaim
      done in hypervisor state in the guest exit path.
      
      With this, the KVM_CAP_PPC_HTM capability returns true (1) even if
      transactional memory is not available to host userspace.
      
      Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      4bb3c7a0
  9. Jan 20, 2018
  10. Jan 18, 2018
    • Paul Mackerras's avatar
      KVM: PPC: Book3S HV: Improve handling of debug-trigger HMIs on POWER9 · d075745d
      Paul Mackerras authored
      
      Hypervisor maintenance interrupts (HMIs) are generated by various
      causes, signalled by bits in the hypervisor maintenance exception
      register (HMER).  In most cases calling OPAL to handle the interrupt
      is the correct thing to do, but the "debug trigger" HMIs signalled by
      PPC bit 17 (bit 46) of HMER are used to invoke software workarounds
      for hardware bugs, and OPAL does not have any code to handle this
      cause.  The debug trigger HMI is used in POWER9 DD2.0 and DD2.1 chips
      to work around a hardware bug in executing vector load instructions to
      cache inhibited memory.  In POWER9 DD2.2 chips, it is generated when
      conditions are detected relating to threads being in TM (transactional
      memory) suspended mode when the core SMT configuration needs to be
      reconfigured.
      
      The kernel currently has code to detect the vector CI load condition,
      but only when the HMI occurs in the host, not when it occurs in a
      guest.  If a HMI occurs in the guest, it is always passed to OPAL, and
      then we always re-sync the timebase, because the HMI cause might have
      been a timebase error, for which OPAL would re-sync the timebase, thus
      removing the timebase offset which KVM applied for the guest.  Since
      we don't know what OPAL did, we don't know whether to subtract the
      timebase offset from the timebase, so instead we re-sync the timebase.
      
      This adds code to determine explicitly what the cause of a debug
      trigger HMI will be.  This is based on a new device-tree property
      under the CPU nodes called ibm,hmi-special-triggers, if it is
      present, or otherwise based on the PVR (processor version register).
      The handling of debug trigger HMIs is pulled out into a separate
      function which can be called from the KVM guest exit code.  If this
      function handles and clears the HMI, and no other HMI causes remain,
      then we skip calling OPAL and we proceed to subtract the guest
      timebase offset from the timebase.
      
      The overall handling for HMIs that occur in the host (i.e. not in a
      KVM guest) is largely unchanged, except that we now don't set the flag
      for the vector CI load workaround on DD2.2 processors.
      
      This also removes a BUG_ON in the KVM code.  BUG_ON is generally not
      useful in KVM guest entry/exit code since it is difficult to handle
      the resulting trap gracefully.
      
      Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      d075745d
  11. Nov 02, 2017
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored
      
      Many source files in the tree are missing licensing information, which
      makes it harder for compliance tools to determine the correct license.
      
      By default all files without license information are under the default
      license of the kernel, which is GPL version 2.
      
      Update the files which contain no license information with the 'GPL-2.0'
      SPDX license identifier.  The SPDX identifier is a legally binding
      shorthand, which can be used instead of the full boiler plate text.
      
      This patch is based on work done by Thomas Gleixner and Kate Stewart and
      Philippe Ombredanne.
      
      How this work was done:
      
      Patches were generated and checked against linux-4.14-rc6 for a subset of
      the use cases:
       - file had no licensing information it it.
       - file was a */uapi/* one with no licensing information in it,
       - file was a */uapi/* one with existing licensing information,
      
      Further patches will be generated in subsequent months to fix up cases
      where non-standard license headers were used, and references to license
      had to be inferred by heuristics based on keywords.
      
      The analysis to determine which SPDX License Identifier to be applied to
      a file was done in a spreadsheet of side by side results from of the
      output of two independent scanners (ScanCode & Windriver) producing SPDX
      tag:value files created by Philippe Ombredanne.  Philippe prepared the
      base worksheet, and did an initial spot review of a few 1000 files.
      
      The 4.13 kernel was the starting point of the analysis with 60,537 files
      assessed.  Kate Stewart did a file by file comparison of the scanner
      results in the spreadsheet to determine which SPDX license identifier(s)
      to be applied to the file. She confirmed any determination that was not
      immediately clear with lawyers working with the Linux Foundation.
      
      Criteria used to select files for SPDX license identifier tagging was:
       - Files considered eligible had to be source code files.
       - Make and config files were included as candidates if they contained >5
         lines of source
       - File already had some variant of a license header in it (even if <5
         lines).
      
      All documentation files were explicitly excluded.
      
      The following heuristics were used to determine which SPDX license
      identifiers to apply.
      
       - when both scanners couldn't find any license traces, file was
         considered to have no license information in it, and the top level
         COPYING file license applied.
      
         For non */uapi/* files that summary was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0                                              11139
      
         and resulted in the first patch in this series.
      
         If that file was a */uapi/* path one, it was "GPL-2.0 WITH
         Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|-------
         GPL-2.0 WITH Linux-syscall-note                        930
      
         and resulted in the second patch in this series.
      
       - if a file had some form of licensing information in it, and was one
         of the */uapi/* ones, it was denoted with the Linux-syscall-note if
         any GPL family license was found in the file or had no licensing in
         it (per prior point).  Results summary:
      
         SPDX license identifier                            # files
         ---------------------------------------------------|------
         GPL-2.0 WITH Linux-syscall-note                       270
         GPL-2.0+ WITH Linux-syscall-note                      169
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
         ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
         LGPL-2.1+ WITH Linux-syscall-note                      15
         GPL-1.0+ WITH Linux-syscall-note                       14
         ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
         LGPL-2.0+ WITH Linux-syscall-note                       4
         LGPL-2.1 WITH Linux-syscall-note                        3
         ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
         ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1
      
         and that resulted in the third patch in this series.
      
       - when the two scanners agreed on the detected license(s), that became
         the concluded license(s).
      
       - when there was disagreement between the two scanners (one detected a
         license but the other didn't, or they both detected different
         licenses) a manual inspection of the file occurred.
      
       - In most cases a manual inspection of the information in the file
         resulted in a clear resolution of the license that should apply (and
         which scanner probably needed to revisit its heuristics).
      
       - When it was not immediately clear, the license identifier was
         confirmed with lawyers working with the Linux Foundation.
      
       - If there was any question as to the appropriate license identifier,
         the file was flagged for further research and to be revisited later
         in time.
      
      In total, over 70 hours of logged manual review was done on the
      spreadsheet to determine the SPDX license identifiers to apply to the
      source files by Kate, Philippe, Thomas and, in some cases, confirmation
      by lawyers working with the Linux Foundation.
      
      Kate also obtained a third independent scan of the 4.13 code base from
      FOSSology, and compared selected files where the other two scanners
      disagreed against that SPDX file, to see if there was new insights.  The
      Windriver scanner is based on an older version of FOSSology in part, so
      they are related.
      
      Thomas did random spot checks in about 500 files from the spreadsheets
      for the uapi headers and agreed with SPDX license identifier in the
      files he inspected. For the non-uapi files Thomas did random spot checks
      in about 15000 files.
      
      In initial set of patches against 4.14-rc6, 3 files were found to have
      copy/paste license identifier errors, and have been fixed to reflect the
      correct identifier.
      
      Additionally Philippe spent 10 hours this week doing a detailed manual
      inspection and review of the 12,461 patched files from the initial patch
      version early this week with:
       - a full scancode scan run, collecting the matched texts, detected
         license ids and scores
       - reviewing anything where there was a license detected (about 500+
         files) to ensure that the applied SPDX license was correct
       - reviewing anything where there was no detection but the patch license
         was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
         SPDX license was correct
      
      This produced a worksheet with 20 files needing minor correction.  This
      worksheet was then exported into 3 different .csv files for the
      different types of files to be modified.
      
      These .csv files were then reviewed by Greg.  Thomas wrote a script to
      parse the csv files and add the proper SPDX tag to the file, in the
      format that the file expected.  This script was further refined by Greg
      based on the output to detect more types of files automatically and to
      distinguish between header and source .c files (which need different
      comment types.)  Finally Greg ran the script using the .csv files to
      generate the patches.
      
      Reviewed-by: default avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: default avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  12. Aug 31, 2017
  13. Aug 10, 2017
  14. Aug 03, 2017
  15. Jul 11, 2017
  16. May 09, 2017
  17. Apr 23, 2017
    • Nicholas Piggin's avatar
      powerpc/64s: Fix POWER9 machine check handler from stop state · 1945bc45
      Nicholas Piggin authored
      
      The ISA specifies power save wakeup due to a machine check exception can
      cause a machine check interrupt (rather than the usual system reset
      interrupt).
      
      The machine check handler copes with this by doing low level machine
      check recovery without restoring full state from idle, then queues up a
      machine check event for logging, then directly executes the same idle
      instruction it woke from. This minimises the work done before recovery
      is performed.
      
      The problem is that it requires machine specific instructions and
      knowledge of the book3s idle code. Currently it only has code to handle
      POWER8 idle, so POWER9 crashes when trying to execute the P8 idle
      instructions which don't exist in ISAv3.0B.
      
      cpu 0x0: Vector: e40 (Emulation Assist) at [c0000000008f3810]
          pc: c000000000008380: machine_check_handle_early+0x130/0x2f0
          lr: c00000000053a098: stop_loop+0x68/0xd0
          sp: c0000000008f3a90
         msr: 9000000000081001
        current = 0xc0000000008a1080
        paca    = 0xc00000000ffd0000   softe: 0        irq_happened: 0x01
          pid   = 0, comm = swapper/0
      
      Instead of going to sleep after recovery, do the usual idle wakeup and
      state restoration by calling into the normal idle wakeup path. This
      reuses the normal idle wakeup paths.
      
      Reviewed-by: default avatarGautham R. Shenoy <ego@linux.vnet.ibm.com>
      Reviewed-by: default avatarMahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>
      Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      1945bc45
  18. Apr 13, 2017
  19. Apr 10, 2017
  20. Feb 09, 2017
  21. Jan 31, 2017
  22. Jan 26, 2017
    • Christophe Leroy's avatar
      powerpc/8xx: Perf events on PPC 8xx · 75b82472
      Christophe Leroy authored
      
      This patch has been reworked since RFC version. In the RFC, this patch
      was preceded by a patch clearing MSR RI for all PPC32 at all time at
      exception prologs. Now MSR RI clearing is done only when this 8xx perf
      events functionality is compiled in, it is therefore limited to 8xx
      and merged inside this patch.
      Other main changes have been to take into account detailed review from
      Peter Zijlstra. The instructions counter has been reworked to behave
      as a free running counter like the three other counters.
      
      The 8xx has no PMU, however some events can be emulated by other means.
      
      This patch implements the following events (as reported by 'perf list'):
        cpu-cycles OR cycles				[Hardware event]
        instructions					[Hardware event]
        dTLB-load-misses				[Hardware cache event]
        iTLB-load-misses				[Hardware cache event]
      
      'cycles' event is implemented using the timebase clock. Timebase clock
      corresponds to CPU clock divided by 16, so number of cycles is
      approximatly 16 times the number of TB ticks
      
      On the 8xx, TLB misses are handled by software. It is therefore
      easy to count all TLB misses each time the TLB miss exception is
      called.
      
      'instructions' is calculated by using instruction watchpoint counter.
      This patch sets counter A to count instructions at address greater
      than 0, hence we count all instructions executed while MSR RI bit is
      set. The counter is set to the maximum which is 0xffff. Every 65535
      instructions, debug instruction breakpoint exception fires. The
      exception handler increments a counter in memory which then
      represent the upper part of the instruction counter. We therefore
      end up with a 48 bits counter. In order to avoid unnecessary overhead
      while no perf event is active, this counter is started when the first
      event referring to this counter is added, and the counter is stopped
      when the last event referring to it is deleted. In order to properly
      support breakpoint exceptions, MSR RI bit has to be unset in exception
      epilogs in order to avoid breakpoint exceptions during critical
      sections during changes to SRR0 and SRR1 would be problematic.
      
      All counters are handled as free running counters.
      
      Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
      Signed-off-by: default avatarScott Wood <oss@buserror.net>
      75b82472
  23. Jan 25, 2017
  24. Nov 23, 2016
  25. Nov 22, 2016
  26. Nov 21, 2016
  27. Nov 14, 2016
  28. Oct 04, 2016
  29. Sep 27, 2016
    • Thomas Huth's avatar
      KVM: PPC: Book3s PR: Allow access to unprivileged MMCR2 register · fa73c3b2
      Thomas Huth authored
      
      The MMCR2 register is available twice, one time with number 785
      (privileged access), and one time with number 769 (unprivileged,
      but it can be disabled completely). In former times, the Linux
      kernel was using the unprivileged register 769 only, but since
      commit 8dd75ccb ("powerpc: Use privileged SPR number
      for MMCR2"), it uses the privileged register 785 instead.
      The KVM-PR code then of course also switched to use the SPR 785,
      but this is causing older guest kernels to crash, since these
      kernels still access 769 instead. So to support older kernels
      with KVM-PR again, we have to support register 769 in KVM-PR, too.
      
      Fixes: 8dd75ccb
      Cc: stable@vger.kernel.org # v3.10+
      Signed-off-by: default avatarThomas Huth <thuth@redhat.com>
      Signed-off-by: default avatarPaul Mackerras <paulus@ozlabs.org>
      fa73c3b2
  30. Sep 25, 2016
    • Christophe Leroy's avatar
      powerpc/8xx: use SPRN_EIE and SPRN_EID to enable/disable interrupts · 834e5a69
      Christophe Leroy authored
      
      The 8xx has two special registers called EID (External Interrupt
      Disable) and EIE (External Interrupt Enable) for clearing/setting
      EE in MSR. It avoids the three instructions set mfmsr/ori/mtmsr or
      mfmsr/rlwinm/mtmsr and it avoids using a general register.
      
      We just have to write something in the special register to change MSR EE
      bit. So we write r0 into the register, regardless of r0 value.
      
      Writing to one of those two special registers also set the MSR RI bit,
      but this bit is only unset during beginning of exception prolog and end
      of exception epilog. When executing C-functions MSR RI is always set.
      
      Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
      Signed-off-by: default avatarScott Wood <oss@buserror.net>
      834e5a69
  31. Sep 13, 2016
  32. Aug 01, 2016
  33. Jul 19, 2016
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