1. 08 May, 2020 4 commits
    • Suravee Suthikulpanit's avatar
      KVM: Introduce kvm_make_all_cpus_request_except() · 54163a34
      Suravee Suthikulpanit authored
      This allows making request to all other vcpus except the one
      specified in the parameter.
      Signed-off-by: default avatarSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
      Message-Id: <1588771076-73790-2-git-send-email-suravee.suthikulpanit@amd.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      54163a34
    • Paolo Bonzini's avatar
      KVM: VMX: pass correct DR6 for GD userspace exit · 45981ded
      Paolo Bonzini authored
      When KVM_EXIT_DEBUG is raised for the disabled-breakpoints case (DR7.GD),
      DR6 was incorrectly copied from the value in the VM.  Instead,
      DR6.BD should be set in order to catch this case.
      
      On AMD this does not need any special code because the processor triggers
      a #DB exception that is intercepted.  However, the testcase would fail
      without the previous patch because both DR6.BS and DR6.BD would be set.
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      45981ded
    • Paolo Bonzini's avatar
      KVM: x86, SVM: isolate vcpu->arch.dr6 from vmcb->save.dr6 · d67668e9
      Paolo Bonzini authored
      There are two issues with KVM_EXIT_DEBUG on AMD, whose root cause is the
      different handling of DR6 on intercepted #DB exceptions on Intel and AMD.
      
      On Intel, #DB exceptions transmit the DR6 value via the exit qualification
      field of the VMCS, and the exit qualification only contains the description
      of the precise event that caused a vmexit.
      
      On AMD, instead the DR6 field of the VMCB is filled in as if the #DB exception
      was to be injected into the guest.  This has two effects when guest debugging
      is in use:
      
      * the guest DR6 is clobbered
      
      * the kvm_run->debug.arch.dr6 field can accumulate more debug events, rather
      than just the last one that happened (the testcase in the next patch covers
      this issue).
      
      This patch fixes both issues by emulating, so to speak, the Intel behavior
      on AMD processors.  The important observation is that (after the previous
      patches) the VMCB value of DR6 is only ever observable from the guest is
      KVM_DEBUGREG_WONT_EXIT is set.  Therefore we can actually set vmcb->save.dr6
      to any value we want as long as KVM_DEBUGREG_WONT_EXIT is clear, which it
      will be if guest debugging is enabled.
      
      Therefore it is possible to enter the guest with an all-zero DR6,
      reconstruct the #DB payload from the DR6 we get at exit time, and let
      kvm_deliver_exception_payload move the newly set bits into vcpu->arch.dr6.
      Some extra bits may be included in the payload if KVM_DEBUGREG_WONT_EXIT
      is set, but this is harmless.
      
      This may not be the most optimized way to deal with this, but it is
      simple and, being confined within SVM code, it gets rid of the set_dr6
      callback and kvm_update_dr6.
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      d67668e9
    • Paolo Bonzini's avatar
      KVM: SVM: keep DR6 synchronized with vcpu->arch.dr6 · 5679b803
      Paolo Bonzini authored
      kvm_x86_ops.set_dr6 is only ever called with vcpu->arch.dr6 as the
      second argument.  Ensure that the VMCB value is synchronized to
      vcpu->arch.dr6 on #DB (both "normal" and nested) and nested vmentry, so
      that the current value of DR6 is always available in vcpu->arch.dr6.
      The get_dr6 callback can just access vcpu->arch.dr6 and becomes redundant.
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      5679b803
  2. 07 May, 2020 6 commits
  3. 06 May, 2020 4 commits
  4. 04 May, 2020 6 commits
  5. 01 May, 2020 1 commit
    • Marc Zyngier's avatar
      KVM: arm64: Fix 32bit PC wrap-around · 0225fd5e
      Marc Zyngier authored
      In the unlikely event that a 32bit vcpu traps into the hypervisor
      on an instruction that is located right at the end of the 32bit
      range, the emulation of that instruction is going to increment
      PC past the 32bit range. This isn't great, as userspace can then
      observe this value and get a bit confused.
      
      Conversly, userspace can do things like (in the context of a 64bit
      guest that is capable of 32bit EL0) setting PSTATE to AArch64-EL0,
      set PC to a 64bit value, change PSTATE to AArch32-USR, and observe
      that PC hasn't been truncated. More confusion.
      
      Fix both by:
      - truncating PC increments for 32bit guests
      - sanitizing all 32bit regs every time a core reg is changed by
        userspace, and that PSTATE indicates a 32bit mode.
      
      Cc: stable@vger.kernel.org
      Acked-by: default avatarWill Deacon <will@kernel.org>
      Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
      0225fd5e
  6. 30 Apr, 2020 3 commits
  7. 23 Apr, 2020 5 commits
  8. 22 Apr, 2020 2 commits
  9. 21 Apr, 2020 2 commits
  10. 20 Apr, 2020 4 commits
  11. 19 Apr, 2020 3 commits
    • Linus Torvalds's avatar
      Linux 5.7-rc2 · ae83d0b4
      Linus Torvalds authored
      ae83d0b4
    • Brian Geffon's avatar
      mm: Fix MREMAP_DONTUNMAP accounting on VMA merge · dadbd85f
      Brian Geffon authored
      When remapping a mapping where a portion of a VMA is remapped
      into another portion of the VMA it can cause the VMA to become
      split. During the copy_vma operation the VMA can actually
      be remerged if it's an anonymous VMA whose pages have not yet
      been faulted. This isn't normally a problem because at the end
      of the remap the original portion is unmapped causing it to
      become split again.
      
      However, MREMAP_DONTUNMAP leaves that original portion in place which
      means that the VMA which was split and then remerged is not actually
      split at the end of the mremap. This patch fixes a bug where
      we don't detect that the VMAs got remerged and we end up
      putting back VM_ACCOUNT on the next mapping which is completely
      unreleated. When that next mapping is unmapped it results in
      incorrectly unaccounting for the memory which was never accounted,
      and eventually we will underflow on the memory comittment.
      
      There is also another issue which is similar, we're currently
      accouting for the number of pages in the new_vma but that's wrong.
      We need to account for the length of the remap operation as that's
      all that is being added. If there was a mapping already at that
      location its comittment would have been adjusted as part of
      the munmap at the start of the mremap.
      
      A really simple repro can be seen in:
      https://gist.github.com/bgaff/e101ce99da7d9a8c60acc641d07f312c
      
      Fixes: e346b381 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()")
      Reported-by: default avatarsyzbot <syzkaller@googlegroups.com>
      Signed-off-by: default avatarBrian Geffon <bgeffon@google.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dadbd85f
    • Linus Torvalds's avatar
      Merge tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux · 86cc3398
      Linus Torvalds authored
      Pull clk fixes from Stephen Boyd:
       "Two build fixes for a couple clk drivers and a fix for the Unisoc
        serial clk where we want to keep it on for earlycon"
      
      * tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
        clk: sprd: don't gate uart console clock
        clk: mmp2: fix link error without mmp2
        clk: asm9260: fix __clk_hw_register_fixed_rate_with_accuracy typo
      86cc3398