1. 16 6月, 2017 1 次提交
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      KVM: PPC: Book3S HV: Save/restore host values of debug registers · 7ceaa6dc
      Paul Mackerras 提交于
      At present, HV KVM on POWER8 and POWER9 machines loses any instruction
      or data breakpoint set in the host whenever a guest is run.
      Instruction breakpoints are currently only used by xmon, but ptrace
      and the perf_event subsystem can set data breakpoints as well as xmon.
      
      To fix this, we save the host values of the debug registers (CIABR,
      DAWR and DAWRX) before entering the guest and restore them on exit.
      To provide space to save them in the stack frame, we expand the stack
      frame allocated by kvmppc_hv_entry() from 112 to 144 bytes.
      
      Fixes: b005255e ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs", 2014-01-08)
      Cc: stable@vger.kernel.org # v3.14+
      Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
      7ceaa6dc
  2. 15 6月, 2017 2 次提交
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      KVM: PPC: Book3S HV: Preserve userspace HTM state properly · 46a704f8
      Paul Mackerras 提交于
      If userspace attempts to call the KVM_RUN ioctl when it has hardware
      transactional memory (HTM) enabled, the values that it has put in the
      HTM-related SPRs TFHAR, TFIAR and TEXASR will get overwritten by
      guest values.  To fix this, we detect this condition and save those
      SPR values in the thread struct, and disable HTM for the task.  If
      userspace goes to access those SPRs or the HTM facility in future,
      a TM-unavailable interrupt will occur and the handler will reload
      those SPRs and re-enable HTM.
      
      If userspace has started a transaction and suspended it, we would
      currently lose the transactional state in the guest entry path and
      would almost certainly get a "TM Bad Thing" interrupt, which would
      cause the host to crash.  To avoid this, we detect this case and
      return from the KVM_RUN ioctl with an EINVAL error, with the KVM
      exit reason set to KVM_EXIT_FAIL_ENTRY.
      
      Fixes: b005255e ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs", 2014-01-08)
      Cc: stable@vger.kernel.org # v3.14+
      Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
      46a704f8
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      KVM: PPC: Book3S HV: Restore critical SPRs to host values on guest exit · 4c3bb4cc
      Paul Mackerras 提交于
      This restores several special-purpose registers (SPRs) to sane values
      on guest exit that were missed before.
      
      TAR and VRSAVE are readable and writable by userspace, and we need to
      save and restore them to prevent the guest from potentially affecting
      userspace execution (not that TAR or VRSAVE are used by any known
      program that run uses the KVM_RUN ioctl).  We save/restore these
      in kvmppc_vcpu_run_hv() rather than on every guest entry/exit.
      
      FSCR affects userspace execution in that it can prohibit access to
      certain facilities by userspace.  We restore it to the normal value
      for the task on exit from the KVM_RUN ioctl.
      
      IAMR is normally 0, and is restored to 0 on guest exit.  However,
      with a radix host on POWER9, it is set to a value that prevents the
      kernel from executing user-accessible memory.  On POWER9, we save
      IAMR on guest entry and restore it on guest exit to the saved value
      rather than 0.  On POWER8 we continue to set it to 0 on guest exit.
      
      PSPB is normally 0.  We restore it to 0 on guest exit to prevent
      userspace taking advantage of the guest having set it non-zero
      (which would allow userspace to set its SMT priority to high).
      
      UAMOR is normally 0.  We restore it to 0 on guest exit to prevent
      the AMR from being used as a covert channel between userspace
      processes, since the AMR is not context-switched at present.
      
      Fixes: b005255e ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs", 2014-01-08)
      Cc: stable@vger.kernel.org # v3.14+
      Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
      4c3bb4cc
  3. 13 6月, 2017 1 次提交
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      KVM: PPC: Book3S HV: Context-switch EBB registers properly · ca8efa1d
      Paul Mackerras 提交于
      This adds code to save the values of three SPRs (special-purpose
      registers) used by userspace to control event-based branches (EBBs),
      which are essentially interrupts that get delivered directly to
      userspace.  These registers are loaded up with guest values when
      entering the guest, and their values are saved when exiting the
      guest, but we were not saving the host values and restoring them
      before going back to userspace.
      
      On POWER8 this would only affect userspace programs which explicitly
      request the use of EBBs and also use the KVM_RUN ioctl, since the
      only source of EBBs on POWER8 is the PMU, and there is an explicit
      enable bit in the PMU registers (and those PMU registers do get
      properly context-switched between host and guest).  On POWER9 there
      is provision for externally-generated EBBs, and these are not subject
      to the control in the PMU registers.
      
      Since these registers only affect userspace, we can save them when
      we first come in from userspace and restore them before returning to
      userspace, rather than saving/restoring the host values on every
      guest entry/exit.  Similarly, we don't need to worry about their
      values on offline secondary threads since they execute in the context
      of the idle task, which never executes in userspace.
      
      Fixes: b005255e ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs", 2014-01-08)
      Cc: stable@vger.kernel.org # v3.14+
      Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
      ca8efa1d
  4. 29 5月, 2017 1 次提交
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      KVM: PPC: Book3S HV: Cope with host using large decrementer mode · 2f272463
      Paul Mackerras 提交于
      POWER9 introduces a new mode for the decrementer register, called
      large decrementer mode, in which the decrementer counter is 56 bits
      wide rather than 32, and reads are sign-extended rather than
      zero-extended.  For the decrementer, this new mode is optional and
      controlled by a bit in the LPCR.  The hypervisor decrementer (HDEC)
      is 56 bits wide on POWER9 and has no mode control.
      
      Since KVM code reads and writes the decrementer and hypervisor
      decrementer registers in a few places, it needs to be aware of the
      need to treat the decrementer value as a 64-bit quantity, and only do
      a 32-bit sign extension when large decrementer mode is not in effect.
      Similarly, the HDEC should always be treated as a 64-bit quantity on
      POWER9.  We define a new EXTEND_HDEC macro to encapsulate the feature
      test for POWER9 and the sign extension.
      
      To enable the sign extension to be removed in large decrementer mode,
      we test the LPCR_LD bit in the host LPCR image stored in the struct
      kvm for the guest.  If is set then large decrementer mode is enabled
      and the sign extension should be skipped.
      
      This is partly based on an earlier patch by Oliver O'Halloran.
      
      Cc: stable@vger.kernel.org # v4.10+
      Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
      2f272463
  5. 12 5月, 2017 3 次提交
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      KVM: PPC: Book3S PR: Don't include SPAPR TCE code on non-pseries platforms · 76d837a4
      Paul Mackerras 提交于
      Commit e91aa8e6 ("KVM: PPC: Enable IOMMU_API for KVM_BOOK3S_64
      permanently", 2017-03-22) enabled the SPAPR TCE code for all 64-bit
      Book 3S kernel configurations in order to simplify the code and
      reduce #ifdefs.  However, 64-bit Book 3S PPC platforms other than
      pseries and powernv don't implement the necessary IOMMU callbacks,
      leading to build failures like the following (for a pasemi config):
      
      scripts/kconfig/conf  --silentoldconfig Kconfig
      warning: (KVM_BOOK3S_64) selects SPAPR_TCE_IOMMU which has unmet direct dependencies (IOMMU_SUPPORT && (PPC_POWERNV || PPC_PSERIES))
      
      ...
      
        CC [M]  arch/powerpc/kvm/book3s_64_vio.o
      /home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_64_vio.c: In function ‘kvmppc_clear_tce’:
      /home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_64_vio.c:363:2: error: implicit declaration of function ‘iommu_tce_xchg’ [-Werror=implicit-function-declaration]
        iommu_tce_xchg(tbl, entry, &hpa, &dir);
        ^
      
      To fix this, we make the inclusion of the SPAPR TCE support, and the
      code that uses it in book3s_vio.c and book3s_vio_hv.c, depend on
      the inclusion of support for the pseries and/or powernv platforms.
      This means that when running a 'pseries' guest on those platforms,
      the guest won't have in-kernel acceleration of the PAPR TCE hypercalls,
      but at least now they compile.
      Reviewed-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
      Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
      76d837a4
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      KVM: PPC: Book3S PR: Check copy_to/from_user return values · 67325e98
      Paul Mackerras 提交于
      The PR KVM implementation of the PAPR HPT hypercalls (H_ENTER etc.)
      access an image of the HPT in userspace memory using copy_from_user
      and copy_to_user.  Recently, the declarations of those functions were
      annotated to indicate that the return value must be checked.  Since
      this code doesn't currently check the return value, this causes
      compile warnings like the ones shown below, and since on PPC the
      default is to compile arch/powerpc with -Werror, this causes the
      build to fail.
      
      To fix this, we check the return values, and if non-zero, fail the
      hypercall being processed with a H_FUNCTION error return value.
      There is really no good error return value to use since PAPR didn't
      envisage the possibility that the hypervisor may not be able to access
      the guest's HPT, and H_FUNCTION (function not supported) seems as
      good as any.
      
      The typical compile warnings look like this:
      
        CC      arch/powerpc/kvm/book3s_pr_papr.o
      /home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_pr_papr.c: In function ‘kvmppc_h_pr_enter’:
      /home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_pr_papr.c:53:2: error: ignoring return value of ‘copy_from_user’, declared with attribute warn_unused_result [-Werror=unused-result]
        copy_from_user(pteg, (void __user *)pteg_addr, sizeof(pteg));
        ^
      /home/paulus/kernel/kvm/arch/powerpc/kvm/book3s_pr_papr.c:74:2: error: ignoring return value of ‘copy_to_user’, declared with attribute warn_unused_result [-Werror=unused-result]
        copy_to_user((void __user *)pteg_addr, hpte, HPTE_SIZE);
        ^
      
      ... etc.
      Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
      67325e98
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      KVM: PPC: Book3S HV: Add radix checks in real-mode hypercall handlers · acde2572
      Paul Mackerras 提交于
      POWER9 running a radix guest will take some hypervisor interrupts
      without going to real mode (turning off the MMU).  This means that
      early hypercall handlers may now be called in virtual mode.  Most of
      the handlers work just fine in both modes, but there are some that
      can crash the host if called in virtual mode, notably the TCE (IOMMU)
      hypercalls H_PUT_TCE, H_STUFF_TCE and H_PUT_TCE_INDIRECT.  These
      already have both a real-mode and a virtual-mode version, so we
      arrange for the real-mode version to return H_TOO_HARD for radix
      guests, which will result in the virtual-mode version being called.
      
      The other hypercall which is sensitive to the MMU mode is H_RANDOM.
      It doesn't have a virtual-mode version, so this adds code to enable
      it to be called in either mode.
      
      An alternative solution was considered which would refuse to call any
      of the early hypercall handlers when doing a virtual-mode exit from a
      radix guest.  However, the XICS-on-XIVE code depends on the XICS
      hypercalls being handled early even for virtual-mode exits, because
      the handlers need to be called before the XIVE vCPU state has been
      pulled off the hardware.  Therefore that solution would have become
      quite invasive and complicated, and was rejected in favour of the
      simpler, though less elegant, solution presented here.
      Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
      Tested-by: NDavid Gibson <david@gibson.dropbear.id.au>
      Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
      acde2572
  6. 28 4月, 2017 1 次提交
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      KVM: PPC: Book3S HV: Avoid preemptibility warning in module initialization · db4b0dfa
      Denis Kirjanov 提交于
      With CONFIG_DEBUG_PREEMPT, get_paca() produces the following warning
      in kvmppc_book3s_init_hv() since it calls debug_smp_processor_id().
      
      There is no real issue with the xics_phys field.
      If paca->kvm_hstate.xics_phys is non-zero on one cpu, it will be
      non-zero on them all.  Therefore this is not fixing any actual
      problem, just the warning.
      
      [  138.521188] BUG: using smp_processor_id() in preemptible [00000000] code: modprobe/5596
      [  138.521308] caller is .kvmppc_book3s_init_hv+0x184/0x350 [kvm_hv]
      [  138.521404] CPU: 5 PID: 5596 Comm: modprobe Not tainted 4.11.0-rc3-00022-gc7e790c5 #1
      [  138.521509] Call Trace:
      [  138.521563] [c0000007d018b810] [c0000000023eef10] .dump_stack+0xe4/0x150 (unreliable)
      [  138.521694] [c0000007d018b8a0] [c000000001f6ec04] .check_preemption_disabled+0x134/0x150
      [  138.521829] [c0000007d018b940] [d00000000a010274] .kvmppc_book3s_init_hv+0x184/0x350 [kvm_hv]
      [  138.521963] [c0000007d018ba00] [c00000000191d5cc] .do_one_initcall+0x5c/0x1c0
      [  138.522082] [c0000007d018bad0] [c0000000023e9494] .do_init_module+0x84/0x240
      [  138.522201] [c0000007d018bb70] [c000000001aade18] .load_module+0x1f68/0x2a10
      [  138.522319] [c0000007d018bd20] [c000000001aaeb30] .SyS_finit_module+0xc0/0xf0
      [  138.522439] [c0000007d018be30] [c00000000191baec] system_call+0x38/0xfc
      Signed-off-by: NDenis Kirjanov <kda@linux-powerpc.org>
      Signed-off-by: NPaul Mackerras <paulus@ozlabs.org>
      db4b0dfa
  7. 27 4月, 2017 2 次提交
  8. 20 4月, 2017 17 次提交
  9. 19 4月, 2017 1 次提交
  10. 11 4月, 2017 2 次提交
  11. 10 4月, 2017 4 次提交
  12. 07 4月, 2017 1 次提交
  13. 06 4月, 2017 1 次提交
  14. 31 3月, 2017 2 次提交
  15. 10 3月, 2017 1 次提交