1. 28 May, 2021 4 commits
    • Paolo Bonzini's avatar
      Merge tag 'kvmarm-fixes-5.13-2' of... · a3d2ec9d
      Paolo Bonzini authored
      Merge tag 'kvmarm-fixes-5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
      
      KVM/arm64 fixes for 5.13, take #2
      
      - Another state update on exit to userspace fix
      - Prevent the creation of mixed 32/64 VMs
      a3d2ec9d
    • Wanpeng Li's avatar
      KVM: X86: Kill off ctxt->ud · b35491e6
      Wanpeng Li authored
      
      
      ctxt->ud is consumed only by x86_decode_insn(), we can kill it off by
      passing emulation_type to x86_decode_insn() and dropping ctxt->ud
      altogether. Tracking that info in ctxt for literally one call is silly.
      Suggested-by: default avatarSean Christopherson <seanjc@google.com>
      Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
      Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
      Message-Id: <1622160097-37633-2-git-send-email-wanpengli@tencent.com>
      b35491e6
    • Wanpeng Li's avatar
      KVM: X86: Fix warning caused by stale emulation context · da6393cd
      Wanpeng Li authored
      Reported by syzkaller:
      
        WARNING: CPU: 7 PID: 10526 at linux/arch/x86/kvm//x86.c:7621 x86_emulate_instruction+0x41b/0x510 [kvm]
        RIP: 0010:x86_emulate_instruction+0x41b/0x510 [kvm]
        Call Trace:
         kvm_mmu_page_fault+0x126/0x8f0 [kvm]
         vmx_handle_exit+0x11e/0x680 [kvm_intel]
         vcpu_enter_guest+0xd95/0x1b40 [kvm]
         kvm_arch_vcpu_ioctl_run+0x377/0x6a0 [kvm]
         kvm_vcpu_ioctl+0x389/0x630 [kvm]
         __x64_sys_ioctl+0x8e/0xd0
         do_syscall_64+0x3c/0xb0
         entry_SYSCALL_64_after_hwframe+0x44/0xae
      
      Commit 4a1e10d5 ("KVM: x86: handle hardware breakpoints during emulation())
      adds hardware breakpoints check before emulation the instruction and parts of
      emulation context initialization, actually we don't have the EMULTYPE_NO_DECODE flag
      here and the emulation context will not be reused. Commit c8848cee ("KVM: x86:
      set ctxt->have_exception in x86_decode_insn()) triggers the warning because it
      catches the stale emulation context has #UD, however, it is not during instruction
      decoding which should result in EMULATION_FAILED. This patch fixes it by moving
      the second part emulation context initialization into init_emulate_ctxt() and
      before hardware breakpoints check. The ctxt->ud will be dropped by a follow-up
      patch.
      
      syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=134683fdd00000
      
      Reported-by: syzbot+71271244f206d17f6441@syzkaller.appspotmail.com
      Fixes: 4a1e10d5
      
       (KVM: x86: handle hardware breakpoints during emulation)
      Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
      Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
      Message-Id: <1622160097-37633-1-git-send-email-wanpengli@tencent.com>
      da6393cd
    • Yuan Yao's avatar
      KVM: X86: Use kvm_get_linear_rip() in single-step and #DB/#BP interception · e87e46d5
      Yuan Yao authored
      
      
      The kvm_get_linear_rip() handles x86/long mode cases well and has
      better readability, __kvm_set_rflags() also use the paired
      function kvm_is_linear_rip() to check the vcpu->arch.singlestep_rip
      set in kvm_arch_vcpu_ioctl_set_guest_debug(), so change the
      "CS.BASE + RIP" code in kvm_arch_vcpu_ioctl_set_guest_debug() and
      handle_exception_nmi() to this one.
      Signed-off-by: default avatarYuan Yao <yuan.yao@intel.com>
      Message-Id: <20210526063828.1173-1-yuan.yao@linux.intel.com>
      Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      e87e46d5
  2. 27 May, 2021 30 commits
    • David Matlack's avatar
      KVM: x86/mmu: Fix comment mentioning skip_4k · bedd9195
      David Matlack authored
      
      
      This comment was left over from a previous version of the patch that
      introduced wrprot_gfn_range, when skip_4k was passed in instead of
      min_level.
      Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
      Message-Id: <20210526163227.3113557-1-dmatlack@google.com>
      Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      bedd9195
    • Marcelo Tosatti's avatar
      KVM: VMX: update vcpu posted-interrupt descriptor when assigning device · a2486020
      Marcelo Tosatti authored
      
      
      For VMX, when a vcpu enters HLT emulation, pi_post_block will:
      
      1) Add vcpu to per-cpu list of blocked vcpus.
      
      2) Program the posted-interrupt descriptor "notification vector"
      to POSTED_INTR_WAKEUP_VECTOR
      
      With interrupt remapping, an interrupt will set the PIR bit for the
      vector programmed for the device on the CPU, test-and-set the
      ON bit on the posted interrupt descriptor, and if the ON bit is clear
      generate an interrupt for the notification vector.
      
      This way, the target CPU wakes upon a device interrupt and wakes up
      the target vcpu.
      
      Problem is that pi_post_block only programs the notification vector
      if kvm_arch_has_assigned_device() is true. Its possible for the
      following to happen:
      
      1) vcpu V HLTs on pcpu P, kvm_arch_has_assigned_device is false,
      notification vector is not programmed
      2) device is assigned to VM
      3) device interrupts vcpu V, sets ON bit
      (notification vector not programmed, so pcpu P remains in idle)
      4) vcpu 0 IPIs vcpu V (in guest), but since pi descriptor ON bit is set,
      kvm_vcpu_kick is skipped
      5) vcpu 0 busy spins on vcpu V's response for several seconds, until
      RCU watchdog NMIs all vCPUs.
      
      To fix this, use the start_assignment kvm_x86_ops callback to kick
      vcpus out of the halt loop, so the notification vector is
      properly reprogrammed to the wakeup vector.
      Reported-by: default avatarPei Zhang <pezhang@redhat.com>
      Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
      Message-Id: <20210526172014.GA29007@fuller.cnet>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      a2486020
    • Marcelo Tosatti's avatar
      KVM: rename KVM_REQ_PENDING_TIMER to KVM_REQ_UNBLOCK · 084071d5
      Marcelo Tosatti authored
      
      
      KVM_REQ_UNBLOCK will be used to exit a vcpu from
      its inner vcpu halt emulation loop.
      
      Rename KVM_REQ_PENDING_TIMER to KVM_REQ_UNBLOCK, switch
      PowerPC to arch specific request bit.
      Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
      
      Message-Id: <20210525134321.303768132@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      084071d5
    • Marcelo Tosatti's avatar
      KVM: x86: add start_assignment hook to kvm_x86_ops · 57ab8794
      Marcelo Tosatti authored
      
      
      Add a start_assignment hook to kvm_x86_ops, which is called when
      kvm_arch_start_assignment is done.
      
      The hook is required to update the wakeup vector of a sleeping vCPU
      when a device is assigned to the guest.
      Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
      
      Message-Id: <20210525134321.254128742@redhat.com>
      Reviewed-by: default avatarPeter Xu <peterx@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      57ab8794
    • Wanpeng Li's avatar
      KVM: LAPIC: Narrow the timer latency between wait_lapic_expire and world switch · 9805cf03
      Wanpeng Li authored
      
      
      Let's treat lapic_timer_advance_ns automatic tuning logic as hypervisor
      overhead, move it before wait_lapic_expire instead of between wait_lapic_expire
      and the world switch, the wait duration should be calculated by the
      up-to-date guest_tsc after the overhead of automatic tuning logic. This
      patch reduces ~30+ cycles for kvm-unit-tests/tscdeadline-latency when testing
      busy waits.
      Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
      Message-Id: <1621339235-11131-5-git-send-email-wanpengli@tencent.com>
      Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      9805cf03
    • Paolo Bonzini's avatar
      selftests: kvm: do only 1 memslot_perf_test run by default · fb0f9479
      Paolo Bonzini authored
      
      
      The test takes a long time with the current implementation of
      memslots, so cut the run time a bit.
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      fb0f9479
    • Joe Richey's avatar
      KVM: X86: Use _BITUL() macro in UAPI headers · fb1070d1
      Joe Richey authored
      Replace BIT() in KVM's UPAI header with _BITUL(). BIT() is not defined
      in the UAPI headers and its usage may cause userspace build errors.
      
      Fixes: fb04a1ed
      
       ("KVM: X86: Implement ring-based dirty memory tracking")
      Signed-off-by: default avatarJoe Richey <joerichey@google.com>
      Message-Id: <20210521085849.37676-3-joerichey94@gmail.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      fb1070d1
    • Axel Rasmussen's avatar
      KVM: selftests: add shared hugetlbfs backing source type · 33090a88
      Axel Rasmussen authored
      
      
      This lets us run the demand paging test on top of a shared
      hugetlbfs-backed area. The "shared" is key, as this allows us to
      exercise userfaultfd minor faults on hugetlbfs.
      Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
      Message-Id: <20210519200339.829146-11-axelrasmussen@google.com>
      Reviewed-by: default avatarBen Gardon <bgardon@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      33090a88
    • Axel Rasmussen's avatar
      KVM: selftests: allow using UFFD minor faults for demand paging · a4b9722a
      Axel Rasmussen authored
      
      
      UFFD handling of MINOR faults is a new feature whose use case is to
      speed up demand paging (compared to MISSING faults). So, it's
      interesting to let this selftest exercise this new mode.
      
      Modify the demand paging test to have the option of using UFFD minor
      faults, as opposed to missing faults. Now, when turning on userfaultfd
      with '-u', the desired mode has to be specified ("MISSING" or "MINOR").
      
      If we're in minor mode, before registering, prefault via the *alias*.
      This way, the guest will trigger minor faults, instead of missing
      faults, and we can UFFDIO_CONTINUE to resolve them.
      
      Modify the page fault handler function to use the right ioctl depending
      on the mode we're running in. In MINOR mode, use UFFDIO_CONTINUE.
      Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
      Message-Id: <20210519200339.829146-10-axelrasmussen@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      a4b9722a
    • Axel Rasmussen's avatar
      KVM: selftests: create alias mappings when using shared memory · 94f3f2b3
      Axel Rasmussen authored
      
      
      When a memory region is added with a src_type specifying that it should
      use some kind of shared memory, also create an alias mapping to the same
      underlying physical pages.
      
      And, add an API so tests can get access to these alias addresses.
      Basically, for a guest physical address, let us look up the analogous
      host *alias* address.
      
      In a future commit, we'll modify the demand paging test to take
      advantage of this to exercise UFFD minor faults. The idea is, we
      pre-fault the underlying pages *via the alias*. When the *guest*
      faults, it gets a "minor" fault (PTEs don't exist yet, but a page is
      already in the page cache). Then, the userfaultfd theads can handle the
      fault: they could potentially modify the underlying memory *via the
      alias* if they wanted to, and then they install the PTEs and let the
      guest carry on via a UFFDIO_CONTINUE ioctl.
      Reviewed-by: default avatarBen Gardon <bgardon@google.com>
      Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
      Message-Id: <20210519200339.829146-9-axelrasmussen@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      94f3f2b3
    • Axel Rasmussen's avatar
      KVM: selftests: add shmem backing source type · c9befd59
      Axel Rasmussen authored
      
      
      This lets us run the demand paging test on top of a shmem-backed area.
      In follow-up commits, we'll 1) leverage this new capability to create an
      alias mapping, and then 2) use the alias mapping to exercise UFFD minor
      faults.
      Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
      Message-Id: <20210519200339.829146-8-axelrasmussen@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      c9befd59
    • Axel Rasmussen's avatar
      KVM: selftests: refactor vm_mem_backing_src_type flags · b3784bc2
      Axel Rasmussen authored
      
      
      Each struct vm_mem_backing_src_alias has a flags field, which denotes
      the flags used to mmap() an area of that type. Previously, this field
      never included MAP_PRIVATE | MAP_ANONYMOUS, because
      vm_userspace_mem_region_add assumed that *all* types would always use
      those flags, and so it hardcoded them.
      
      In a follow-up commit, we'll add a new type: shmem. Areas of this type
      must not have MAP_PRIVATE | MAP_ANONYMOUS, and instead they must have
      MAP_SHARED.
      
      So, refactor things. Make it so that the flags field of
      struct vm_mem_backing_src_alias really is a complete set of flags, and
      don't add in any extras in vm_userspace_mem_region_add. This will let us
      easily tack on shmem.
      Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
      Message-Id: <20210519200339.829146-7-axelrasmussen@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      b3784bc2
    • Axel Rasmussen's avatar
      KVM: selftests: allow different backing source types · 0368c2c1
      Axel Rasmussen authored
      
      
      Add an argument which lets us specify a different backing memory type
      for the test. The default is just to use anonymous, matching existing
      behavior.
      
      This is in preparation for testing UFFD minor faults. For that, we'll
      need to use a new backing memory type which is setup with MAP_SHARED.
      Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
      Message-Id: <20210519200339.829146-6-axelrasmussen@google.com>
      Reviewed-by: default avatarBen Gardon <bgardon@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      0368c2c1
    • Axel Rasmussen's avatar
      KVM: selftests: compute correct demand paging size · 32ffa4f7
      Axel Rasmussen authored
      
      
      This is a preparatory commit needed before we can use different kinds of
      backing pages for guest memory.
      
      Previously, we used perf_test_args.host_page_size, which is the host's
      native page size (commonly 4K). For VM_MEM_SRC_ANONYMOUS this turns out
      to be okay, but in a follow-up commit we want to allow using different
      kinds of backing memory.
      
      Take VM_MEM_SRC_ANONYMOUS_HUGETLB for example. Without this change, if
      we used that backing page type, when we issued a UFFDIO_COPY ioctl we'd
      only do so with 4K, rather than the full 2M of a backing hugepage. In
      this case, UFFDIO_COPY returns -EINVAL (__mcopy_atomic_hugetlb checks
      the size).
      Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
      Message-Id: <20210519200339.829146-5-axelrasmussen@google.com>
      Reviewed-by: default avatarBen Gardon <bgardon@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      32ffa4f7
    • Axel Rasmussen's avatar
      KVM: selftests: simplify setup_demand_paging error handling · 25408e5a
      Axel Rasmussen authored
      
      
      A small cleanup. Our caller writes:
      
        r = setup_demand_paging(...);
        if (r < 0) exit(-r);
      
      Since we're just going to exit anyway, instead of returning an error we
      can just re-use TEST_ASSERT. This makes the caller simpler, as well as
      the function itself - no need to write our branches, etc.
      Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
      Message-Id: <20210519200339.829146-3-axelrasmussen@google.com>
      Reviewed-by: default avatarBen Gardon <bgardon@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      25408e5a
    • David Matlack's avatar
      KVM: selftests: Print a message if /dev/kvm is missing · 2aab4b35
      David Matlack authored
      
      
      If a KVM selftest is run on a machine without /dev/kvm, it will exit
      silently. Make it easy to tell what's happening by printing an error
      message.
      
      Opportunistically consolidate all codepaths that open /dev/kvm into a
      single function so they all print the same message.
      
      This slightly changes the semantics of vm_is_unrestricted_guest() by
      changing a TEST_ASSERT() to exit(KSFT_SKIP). However
      vm_is_unrestricted_guest() is only called in one place
      (x86_64/mmio_warning_test.c) and that is to determine if the test should
      be skipped or not.
      Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
      Message-Id: <20210511202120.1371800-1-dmatlack@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      2aab4b35
    • Axel Rasmussen's avatar
      KVM: selftests: trivial comment/logging fixes · c887d6a1
      Axel Rasmussen authored
      
      
      Some trivial fixes I found while touching related code in this series,
      factored out into a separate commit for easier reviewing:
      
      - s/gor/got/ and add a newline in demand_paging_test.c
      - s/backing_src/src_type/ in a comment to be consistent with the real
        function signature in kvm_util.c
      Signed-off-by: default avatarAxel Rasmussen <axelrasmussen@google.com>
      Message-Id: <20210519200339.829146-2-axelrasmussen@google.com>
      Reviewed-by: default avatarBen Gardon <bgardon@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      c887d6a1
    • David Matlack's avatar
      KVM: selftests: Fix hang in hardware_disable_test · a10453c0
      David Matlack authored
      
      
      If /dev/kvm is not available then hardware_disable_test will hang
      indefinitely because the child process exits before posting to the
      semaphore for which the parent is waiting.
      
      Fix this by making the parent periodically check if the child has
      exited. We have to be careful to forward the child's exit status to
      preserve a KSFT_SKIP status.
      
      I considered just checking for /dev/kvm before creating the child
      process, but there are so many other reasons why the child could exit
      early that it seemed better to handle that as general case.
      
      Tested:
      
      $ ./hardware_disable_test
      /dev/kvm not available, skipping test
      $ echo $?
      4
      $ modprobe kvm_intel
      $ ./hardware_disable_test
      $ echo $?
      0
      Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
      Message-Id: <20210514230521.2608768-1-dmatlack@google.com>
      Reviewed-by: Andrew Jones's avatarAndrew Jones <drjones@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      a10453c0
    • David Matlack's avatar
      KVM: selftests: Ignore CPUID.0DH.1H in get_cpuid_test · 50bc913d
      David Matlack authored
      
      
      Similar to CPUID.0DH.0H this entry depends on the vCPU's XCR0 register
      and IA32_XSS MSR. Since this test does not control for either before
      assigning the vCPU's CPUID, these entries will not necessarily match
      the supported CPUID exposed by KVM.
      
      This fixes get_cpuid_test on Cascade Lake CPUs.
      Suggested-by: default avatarJim Mattson <jmattson@google.com>
      Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
      Message-Id: <20210519211345.3944063-1-dmatlack@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      50bc913d
    • David Matlack's avatar
      KVM: selftests: Fix 32-bit truncation of vm_get_max_gfn() · ef4c9f4f
      David Matlack authored
      vm_get_max_gfn() casts vm->max_gfn from a uint64_t to an unsigned int,
      which causes the upper 32-bits of the max_gfn to get truncated.
      
      Nobody noticed until now likely because vm_get_max_gfn() is only used
      as a mechanism to create a memslot in an unused region of the guest
      physical address space (the top), and the top of the 32-bit physical
      address space was always good enough.
      
      This fix reveals a bug in memslot_modification_stress_test which was
      trying to create a dummy memslot past the end of guest physical memory.
      Fix that by moving the dummy memslot lower.
      
      Fixes: 52200d0d
      
       ("KVM: selftests: Remove duplicate guest mode handling")
      Reviewed-by: default avatarVenkatesh Srinivas <venkateshs@chromium.org>
      Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
      Message-Id: <20210521173828.1180619-1-dmatlack@google.com>
      Reviewed-by: Andrew Jones's avatarAndrew Jones <drjones@redhat.com>
      Reviewed-by: default avatarPeter Xu <peterx@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      ef4c9f4f
    • Maciej S. Szmigiero's avatar
      KVM: selftests: add a memslot-related performance benchmark · cad347fa
      Maciej S. Szmigiero authored
      
      
      This benchmark contains the following tests:
      * Map test, where the host unmaps guest memory while the guest writes to
      it (maps it).
      
      The test is designed in a way to make the unmap operation on the host
      take a negligible amount of time in comparison with the mapping
      operation in the guest.
      
      The test area is actually split in two: the first half is being mapped
      by the guest while the second half in being unmapped by the host.
      Then a guest <-> host sync happens and the areas are reversed.
      
      * Unmap test which is broadly similar to the above map test, but it is
      designed in an opposite way: to make the mapping operation in the guest
      take a negligible amount of time in comparison with the unmap operation
      on the host.
      This test is available in two variants: with per-page unmap operation
      or a chunked one (using 2 MiB chunk size).
      
      * Move active area test which involves moving the last (highest gfn)
      memslot a bit back and forth on the host while the guest is
      concurrently writing around the area being moved (including over the
      moved memslot).
      
      * Move inactive area test which is similar to the previous move active
      area test, but now guest writes all happen outside of the area being
      moved.
      
      * Read / write test in which the guest writes to the beginning of each
      page of the test area while the host writes to the middle of each such
      page.
      Then each side checks the values the other side has written.
      This particular test is not expected to give different results depending
      on particular memslots implementation, it is meant as a rough sanity
      check and to provide insight on the spread of test results expected.
      
      Each test performs its operation in a loop until a test period ends
      (this is 5 seconds by default, but it is configurable).
      Then the total count of loops done is divided by the actual elapsed
      time to give the test result.
      
      The tests have a configurable memslot cap with the "-s" test option, by
      default the system maximum is used.
      Each test is repeated a particular number of times (by default 20
      times), the best result achieved is printed.
      
      The test memory area is divided equally between memslots, the reminder
      is added to the last memslot.
      The test area size does not depend on the number of memslots in use.
      
      The tests also measure the time that it took to add all these memslots.
      The best result from the tests that use the whole test area is printed
      after all the requested tests are done.
      
      In general, these tests are designed to use as much memory as possible
      (within reason) while still doing 100+ loops even on high memslot counts
      with the default test length.
      Increasing the test runtime makes it increasingly more likely that some
      event will happen on the system during the test run, which might lower
      the test result.
      Signed-off-by: default avatarMaciej S. Szmigiero <maciej.szmigiero@oracle.com>
      Reviewed-by: Andrew Jones's avatarAndrew Jones <drjones@redhat.com>
      Message-Id: <8d31bb3d92bc8fa33a9756fa802ee14266ab994e.1618253574.git.maciej.szmigiero@oracle.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      cad347fa
    • Maciej S. Szmigiero's avatar
      KVM: selftests: Keep track of memslots more efficiently · 22721a56
      Maciej S. Szmigiero authored
      
      
      The KVM selftest framework was using a simple list for keeping track of
      the memslots currently in use.
      This resulted in lookups and adding a single memslot being O(n), the
      later due to linear scanning of the existing memslot set to check for
      the presence of any conflicting entries.
      
      Before this change, benchmarking high count of memslots was more or less
      impossible as pretty much all the benchmark time was spent in the
      selftest framework code.
      
      We can simply use a rbtree for keeping track of both of gfn and hva.
      We don't need an interval tree for hva here as we can't have overlapping
      memslots because we allocate a completely new memory chunk for each new
      memslot.
      Signed-off-by: default avatarMaciej S. Szmigiero <maciej.szmigiero@oracle.com>
      Reviewed-by: Andrew Jones's avatarAndrew Jones <drjones@redhat.com>
      Message-Id: <b12749d47ee860468240cf027412c91b76dbe3db.1618253574.git.maciej.szmigiero@oracle.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      22721a56
    • Paolo Bonzini's avatar
      selftests: kvm: fix potential issue with ELF loading · a13534d6
      Paolo Bonzini authored
      
      
      vm_vaddr_alloc() sets up GVA to GPA mapping page by page; therefore, GPAs
      may not be continuous if same memslot is used for data and page table allocation.
      
      kvm_vm_elf_load() however expects a continuous range of HVAs (and thus GPAs)
      because it does not try to read file data page by page.  Fix this mismatch
      by allocating memory in one step.
      Reported-by: default avatarZhenzhong Duan <zhenzhong.duan@intel.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      a13534d6
    • Zhenzhong Duan's avatar
      selftests: kvm: make allocation of extra memory take effect · 39fe2fc9
      Zhenzhong Duan authored
      
      
      The extra memory pages is missed to be allocated during VM creating.
      perf_test_util and kvm_page_table_test use it to alloc extra memory
      currently.
      
      Fix it by adding extra_mem_pages to the total memory calculation before
      allocate.
      Signed-off-by: default avatarZhenzhong Duan <zhenzhong.duan@intel.com>
      Message-Id: <20210512043107.30076-1-zhenzhong.duan@intel.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      39fe2fc9
    • Wanpeng Li's avatar
      KVM: X86: hyper-v: Task srcu lock when accessing kvm_memslots() · da6d63a0
      Wanpeng Li authored
         WARNING: suspicious RCU usage
         5.13.0-rc1 #4 Not tainted
         -----------------------------
         ./include/linux/kvm_host.h:710 suspicious rcu_dereference_check() usage!
      
        other info that might help us debug this:
      
        rcu_scheduler_active = 2, debug_locks = 1
         1 lock held by hyperv_clock/8318:
          #0: ffffb6b8cb05a7d8 (&hv->hv_lock){+.+.}-{3:3}, at: kvm_hv_invalidate_tsc_page+0x3e/0xa0 [kvm]
      
        stack backtrace:
        CPU: 3 PID: 8318 Comm: hyperv_clock Not tainted 5.13.0-rc1 #4
        Call Trace:
         dump_stack+0x87/0xb7
         lockdep_rcu_suspicious+0xce/0xf0
         kvm_write_guest_page+0x1c1/0x1d0 [kvm]
         kvm_write_guest+0x50/0x90 [kvm]
         kvm_hv_invalidate_tsc_page+0x79/0xa0 [kvm]
         kvm_gen_update_masterclock+0x1d/0x110 [kvm]
         kvm_arch_vm_ioctl+0x2a7/0xc50 [kvm]
         kvm_vm_ioctl+0x123/0x11d0 [kvm]
         __x64_sys_ioctl+0x3ed/0x9d0
         do_syscall_64+0x3d/0x80
         entry_SYSCALL_64_after_hwframe+0x44/0xae
      
      kvm_memslots() will be called by kvm_write_guest(), so we should take the srcu lock.
      
      Fixes: e880c6ea
      
       (KVM: x86: hyper-v: Prevent using not-yet-updated TSC page by secondary CPUs)
      Reviewed-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
      Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
      Message-Id: <1621339235-11131-4-git-send-email-wanpengli@tencent.com>
      Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      da6d63a0
    • Wanpeng Li's avatar
      KVM: X86: Fix vCPU preempted state from guest's point of view · 1eff0ada
      Wanpeng Li authored
      Commit 66570e96 (kvm: x86: only provide PV features if enabled in guest's
      CPUID) avoids to access pv tlb shootdown host side logic when this pv feature
      is not exposed to guest, however, kvm_steal_time.preempted not only leveraged
      by pv tlb shootdown logic but also mitigate the lock holder preemption issue.
      From guest's point of view, vCPU is always preempted since we lose the reset
      of kvm_steal_time.preempted before vmentry if pv tlb shootdown feature is not
      exposed. This patch fixes it by clearing kvm_steal_time.preempted before
      vmentry.
      
      Fixes: 66570e96
      
       (kvm: x86: only provide PV features if enabled in guest's CPUID)
      Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
      Message-Id: <1621339235-11131-3-git-send-email-wanpengli@tencent.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      1eff0ada
    • Wanpeng Li's avatar
      KVM: X86: Bail out of direct yield in case of under-committed scenarios · 72b268a8
      Wanpeng Li authored
      
      
      In case of under-committed scenarios, vCPUs can be scheduled easily;
      kvm_vcpu_yield_to adds extra overhead, and it is also common to see
      when vcpu->ready is true but yield later failing due to p->state is
      TASK_RUNNING.
      
      Let's bail out in such scenarios by checking the length of current cpu
      runqueue, which can be treated as a hint of under-committed instead of
      guarantee of accuracy. 30%+ of directed-yield attempts can now avoid
      the expensive lookups in kvm_sched_yield() in an under-committed scenario.
      Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
      Message-Id: <1621339235-11131-2-git-send-email-wanpengli@tencent.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      72b268a8
    • Wanpeng Li's avatar
      KVM: PPC: exit halt polling on need_resched() · 6bd5b743
      Wanpeng Li authored
      This is inspired by commit 262de410
      
       (kvm: exit halt polling on
      need_resched() as well). Due to PPC implements an arch specific halt
      polling logic, we have to the need_resched() check there as well. This
      patch adds a helper function that can be shared between book3s and generic
      halt-polling loops.
      Reviewed-by: default avatarDavid Matlack <dmatlack@google.com>
      Reviewed-by: default avatarVenkatesh Srinivas <venkateshs@chromium.org>
      Cc: Ben Segall <bsegall@google.com>
      Cc: Venkatesh Srinivas <venkateshs@chromium.org>
      Cc: Jim Mattson <jmattson@google.com>
      Cc: David Matlack <dmatlack@google.com>
      Cc: Paul Mackerras <paulus@ozlabs.org>
      Cc: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
      Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
      Message-Id: <1621339235-11131-1-git-send-email-wanpengli@tencent.com>
      [Make the function inline. - Paolo]
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      6bd5b743
    • Marc Zyngier's avatar
      KVM: arm64: Prevent mixed-width VM creation · 66e94d5c
      Marc Zyngier authored
      
      
      It looks like we have tolerated creating mixed-width VMs since...
      forever. However, that was never the intention, and we'd rather
      not have to support that pointless complexity.
      
      Forbid such a setup by making sure all the vcpus have the same
      register width.
      Reported-by: Steven Price's avatarSteven Price <steven.price@arm.com>
      Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
      Cc: stable@vger.kernel.org
      Acked-by: Mark Rutland's avatarMark Rutland <mark.rutland@arm.com>
      Link: https://lore.kernel.org/r/20210524170752.1549797-1-maz@kernel.org
      66e94d5c
    • Zenghui Yu's avatar
      KVM: arm64: Resolve all pending PC updates before immediate exit · e3e880bb
      Zenghui Yu authored
      Commit 26778aaa ("KVM: arm64: Commit pending PC adjustemnts before
      returning to userspace") fixed the PC updating issue by forcing an explicit
      synchronisation of the exception state on vcpu exit to userspace.
      
      However, we forgot to take into account the case where immediate_exit is
      set by userspace and KVM_RUN will exit immediately. Fix it by resolving all
      pending PC updates before returning to userspace.
      
      Since __kvm_adjust_pc() relies on a loaded vcpu context, I moved the
      immediate_exit checking right after vcpu_load(). We will get some overhead
      if immediate_exit is true (which should hopefully be rare).
      
      Fixes: 26778aaa
      
       ("KVM: arm64: Commit pending PC adjustemnts before returning to userspace")
      Signed-off-by: default avatarZenghui Yu <yuzenghui@huawei.com>
      Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
      Link: https://lore.kernel.org/r/20210526141831.1662-1-yuzenghui@huawei.com
      Cc: stable@vger.kernel.org # 5.11
      e3e880bb
  3. 24 May, 2021 3 commits
  4. 17 May, 2021 1 commit
  5. 15 May, 2021 2 commits
    • Marc Zyngier's avatar
      KVM: arm64: Fix debug register indexing · cb853ded
      Marc Zyngier authored
      Commit 03fdfb26 ("KVM: arm64: Don't write junk to sysregs on
      reset") flipped the register number to 0 for all the debug registers
      in the sysreg table, hereby indicating that these registers live
      in a separate shadow structure.
      
      However, the author of this patch failed to realise that all the
      accessors are using that particular index instead of the register
      encoding, resulting in all the registers hitting index 0. Not quite
      a valid implementation of the architecture...
      
      Address the issue by fixing all the accessors to use the CRm field
      of the encoding, which contains the debug register index.
      
      Fixes: 03fdfb26
      
       ("KVM: arm64: Don't write junk to sysregs on reset")
      Reported-by: default avatarRicardo Koller <ricarkol@google.com>
      Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
      Cc: stable@vger.kernel.org
      cb853ded
    • Marc Zyngier's avatar
      KVM: arm64: Commit pending PC adjustemnts before returning to userspace · 26778aaa
      Marc Zyngier authored
      
      
      KVM currently updates PC (and the corresponding exception state)
      using a two phase approach: first by setting a set of flags,
      then by converting these flags into a state update when the vcpu
      is about to enter the guest.
      
      However, this creates a disconnect with userspace if the vcpu thread
      returns there with any exception/PC flag set. In this case, the exposed
      context is wrong, as userspace doesn't have access to these flags
      (they aren't architectural). It also means that these flags are
      preserved across a reset, which isn't expected.
      
      To solve this problem, force an explicit synchronisation of the
      exception state on vcpu exit to userspace. As an optimisation
      for nVHE systems, only perform this when there is something pending.
      Reported-by: default avatarZenghui Yu <yuzenghui@huawei.com>
      Reviewed-by: Alexandru Elisei's avatarAlexandru Elisei <alexandru.elisei@arm.com>
      Reviewed-by: default avatarZenghui Yu <yuzenghui@huawei.com>
      Tested-by: default avatarZenghui Yu <yuzenghui@huawei.com>
      Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
      Cc: stable@vger.kernel.org # 5.11
      26778aaa