1. 25 Oct, 2021 7 commits
  2. 20 Oct, 2021 2 commits
  3. 28 Sep, 2021 1 commit
  4. 27 Sep, 2021 1 commit
    • Zhenzhong Duan's avatar
      KVM: VMX: Fix a TSX_CTRL_CPUID_CLEAR field mask issue · 5c49d185
      Zhenzhong Duan authored
      When updating the host's mask for its MSR_IA32_TSX_CTRL user return entry,
      clear the mask in the found uret MSR instead of vmx->guest_uret_msrs[i].
      Modifying guest_uret_msrs directly is completely broken as 'i' does not
      point at the MSR_IA32_TSX_CTRL entry.  In fact, it's guaranteed to be an
      out-of-bounds accesses as is always set to kvm_nr_uret_msrs in a prior
      loop. By sheer dumb luck, the fallout is limited to "only" failing to
      preserve the host's TSX_CTRL_CPUID_CLEAR.  The out-of-bounds access is
      benign as it's guaranteed to clear a bit in a guest MSR value, which are
      always zero at vCPU creation on both x86-64 and i386.
      
      Cc: stable@vger.kernel.org
      Fixes: 8ea8b8d6 ("KVM: VMX: Use common x86's uret MSR list as the one true list")
      Signed-off-by: default avatarZhenzhong Duan <zhenzhong.duan@intel.com>
      Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
      Message-Id: <20210926015545.281083-1-zhenzhong.duan@intel.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      5c49d185
  5. 24 Sep, 2021 3 commits
  6. 23 Sep, 2021 7 commits
  7. 22 Sep, 2021 19 commits
    • Fares Mehanna's avatar
      kvm: x86: Add AMD PMU MSRs to msrs_to_save_all[] · e1fc1553
      Fares Mehanna authored
      Intel PMU MSRs is in msrs_to_save_all[], so add AMD PMU MSRs to have a
      consistent behavior between Intel and AMD when using KVM_GET_MSRS,
      KVM_SET_MSRS or KVM_GET_MSR_INDEX_LIST.
      
      We have to add legacy and new MSRs to handle guests running without
      X86_FEATURE_PERFCTR_CORE.
      Signed-off-by: default avatarFares Mehanna <faresx@amazon.de>
      Message-Id: <20210915133951.22389-1-faresx@amazon.de>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      e1fc1553
    • Maxim Levitsky's avatar
      KVM: x86: nVMX: re-evaluate emulation_required on nested VM exit · dbab610a
      Maxim Levitsky authored
      If L1 had invalid state on VM entry (can happen on SMM transactions
      when we enter from real mode, straight to nested guest),
      
      then after we load 'host' state from VMCS12, the state has to become
      valid again, but since we load the segment registers with
      __vmx_set_segment we weren't always updating emulation_required.
      
      Update emulation_required explicitly at end of load_vmcs12_host_state.
      Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      Message-Id: <20210913140954.165665-8-mlevitsk@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      dbab610a
    • Maxim Levitsky's avatar
      KVM: x86: nVMX: don't fail nested VM entry on invalid guest state if !from_vmentry · c8607e4a
      Maxim Levitsky authored
      It is possible that when non root mode is entered via special entry
      (!from_vmentry), that is from SMM or from loading the nested state,
      the L2 state could be invalid in regard to non unrestricted guest mode,
      but later it can become valid.
      
      (for example when RSM emulation restores segment registers from SMRAM)
      
      Thus delay the check to VM entry, where we will check this and fail.
      Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      Message-Id: <20210913140954.165665-7-mlevitsk@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      c8607e4a
    • Maxim Levitsky's avatar
      KVM: x86: VMX: synthesize invalid VM exit when emulating invalid guest state · c42dec14
      Maxim Levitsky authored
      Since no actual VM entry happened, the VM exit information is stale.
      To avoid this, synthesize an invalid VM guest state VM exit.
      Suggested-by: default avatarSean Christopherson <seanjc@google.com>
      Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      Message-Id: <20210913140954.165665-6-mlevitsk@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      c42dec14
    • Maxim Levitsky's avatar
      KVM: x86: nSVM: refactor svm_leave_smm and smm_enter_smm · 136a55c0
      Maxim Levitsky authored
      Use return statements instead of nested if, and fix error
      path to free all the maps that were allocated.
      Suggested-by: default avatarSean Christopherson <seanjc@google.com>
      Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      Message-Id: <20210913140954.165665-2-mlevitsk@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      136a55c0
    • Maxim Levitsky's avatar
      KVM: x86: SVM: call KVM_REQ_GET_NESTED_STATE_PAGES on exit from SMM mode · e85d3e7b
      Maxim Levitsky authored
      Currently the KVM_REQ_GET_NESTED_STATE_PAGES on SVM only reloads PDPTRs,
      and MSR bitmap, with former not really needed for SMM as SMM exit code
      reloads them again from SMRAM'S CR3, and later happens to work
      since MSR bitmap isn't modified while in SMM.
      
      Still it is better to be consistient with VMX.
      Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      Message-Id: <20210913140954.165665-5-mlevitsk@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      e85d3e7b
    • Maxim Levitsky's avatar
      KVM: x86: reset pdptrs_from_userspace when exiting smm · 37687c40
      Maxim Levitsky authored
      When exiting SMM, pdpts are loaded again from the guest memory.
      
      This fixes a theoretical bug, when exit from SMM triggers entry to the
      nested guest which re-uses some of the migration
      code which uses this flag as a workaround for a legacy userspace.
      Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      Message-Id: <20210913140954.165665-4-mlevitsk@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      37687c40
    • Maxim Levitsky's avatar
      KVM: x86: nSVM: restore the L1 host state prior to resuming nested guest on SMM exit · e2e6e449
      Maxim Levitsky authored
      Otherwise guest entry code might see incorrect L1 state (e.g paging state).
      
      Fixes: 37be407b ("KVM: nSVM: Fix L1 state corruption upon return from SMM")
      Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      Message-Id: <20210913140954.165665-3-mlevitsk@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      e2e6e449
    • Vitaly Kuznetsov's avatar
      KVM: nVMX: Filter out all unsupported controls when eVMCS was activated · 8d68bad6
      Vitaly Kuznetsov authored
      Windows Server 2022 with Hyper-V role enabled failed to boot on KVM when
      enlightened VMCS is advertised. Debugging revealed there are two exposed
      secondary controls it is not happy with: SECONDARY_EXEC_ENABLE_VMFUNC and
      SECONDARY_EXEC_SHADOW_VMCS. These controls are known to be unsupported,
      as there are no corresponding fields in eVMCSv1 (see the comment above
      EVMCS1_UNSUPPORTED_2NDEXEC definition).
      
      Previously, commit 31de3d25 ("x86/kvm/hyper-v: move VMX controls
      sanitization out of nested_enable_evmcs()") introduced the required
      filtering mechanism for VMX MSRs but for some reason put only known
      to be problematic (and not full EVMCS1_UNSUPPORTED_* lists) controls
      there.
      
      Note, Windows Server 2022 seems to have gained some sanity check for VMX
      MSRs: it doesn't even try to launch a guest when there's something it
      doesn't like, nested_evmcs_check_controls() mechanism can't catch the
      problem.
      
      Let's be bold this time and instead of playing whack-a-mole just filter out
      all unsupported controls from VMX MSRs.
      
      Fixes: 31de3d25 ("x86/kvm/hyper-v: move VMX controls sanitization out of nested_enable_evmcs()")
      Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
      Message-Id: <20210907163530.110066-1-vkuznets@redhat.com>
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      8d68bad6
    • Sean Christopherson's avatar
      KVM: KVM: Use cpumask_available() to check for NULL cpumask when kicking vCPUs · 0bbc2ca8
      Sean Christopherson authored
      Check for a NULL cpumask_var_t when kicking multiple vCPUs via
      cpumask_available(), which performs a !NULL check if and only if cpumasks
      are configured to be allocated off-stack.  This is a meaningless
      optimization, e.g. avoids a TEST+Jcc and TEST+CMOV on x86, but more
      importantly helps document that the NULL check is necessary even though
      all callers pass in a local variable.
      
      No functional change intended.
      
      Cc: Lai Jiangshan <jiangshanlai@gmail.com>
      Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
      Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
      Message-Id: <20210827092516.1027264-3-vkuznets@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      0bbc2ca8
    • Sean Christopherson's avatar
      KVM: Clean up benign vcpu->cpu data races when kicking vCPUs · 85b64045
      Sean Christopherson authored
      Fix a benign data race reported by syzbot+KCSAN[*] by ensuring vcpu->cpu
      is read exactly once, and by ensuring the vCPU is booted from guest mode
      if kvm_arch_vcpu_should_kick() returns true.  Fix a similar race in
      kvm_make_vcpus_request_mask() by ensuring the vCPU is interrupted if
      kvm_request_needs_ipi() returns true.
      
      Reading vcpu->cpu before vcpu->mode (via kvm_arch_vcpu_should_kick() or
      kvm_request_needs_ipi()) means the target vCPU could get migrated (change
      vcpu->cpu) and enter !OUTSIDE_GUEST_MODE between reading vcpu->cpud and
      reading vcpu->mode.  If that happens, the kick/IPI will be sent to the
      old pCPU, not the new pCPU that is now running the vCPU or reading SPTEs.
      
      Although failing to kick the vCPU is not exactly ideal, practically
      speaking it cannot cause a functional issue unless there is also a bug in
      the caller, and any such bug would exist regardless of kvm_vcpu_kick()'s
      behavior.
      
      The purpose of sending an IPI is purely to get a vCPU into the host (or
      out of reading SPTEs) so that the vCPU can recognize a change in state,
      e.g. a KVM_REQ_* request.  If vCPU's handling of the state change is
      required for correctness, KVM must ensure either the vCPU sees the change
      before entering the guest, or that the sender sees the vCPU as running in
      guest mode.  All architectures handle this by (a) sending the request
      before calling kvm_vcpu_kick() and (b) checking for requests _after_
      setting vcpu->mode.
      
      x86's READING_SHADOW_PAGE_TABLES has similar requirements; KVM needs to
      ensure it kicks and waits for vCPUs that started reading SPTEs _before_
      MMU changes were finalized, but any vCPU that starts reading after MMU
      changes were finalized will see the new state and can continue on
      uninterrupted.
      
      For uses of kvm_vcpu_kick() that are not paired with a KVM_REQ_*, e.g.
      x86's kvm_arch_sync_dirty_log(), the order of the kick must not be relied
      upon for functional correctness, e.g. in the dirty log case, userspace
      cannot assume it has a 100% complete log if vCPUs are still running.
      
      All that said, eliminate the benign race since the cost of doing so is an
      "extra" atomic cmpxchg() in the case where the target vCPU is loaded by
      the current pCPU or is not loaded at all.  I.e. the kick will be skipped
      due to kvm_vcpu_exiting_guest_mode() seeing a compatible vcpu->mode as
      opposed to the kick being skipped because of the cpu checks.
      
      Keep the "cpu != me" checks even though they appear useless/impossible at
      first glance.  x86 processes guest IPI writes in a fast path that runs in
      IN_GUEST_MODE, i.e. can call kvm_vcpu_kick() from IN_GUEST_MODE.  And
      calling kvm_vm_bugged()->kvm_make_vcpus_request_mask() from IN_GUEST or
      READING_SHADOW_PAGE_TABLES is perfectly reasonable.
      
      Note, a race with the cpu_online() check in kvm_vcpu_kick() likely
      persists, e.g. the vCPU could exit guest mode and get offlined between
      the cpu_online() check and the sending of smp_send_reschedule().  But,
      the online check appears to exist only to avoid a WARN in x86's
      native_smp_send_reschedule() that fires if the target CPU is not online.
      The reschedule WARN exists because CPU offlining takes the CPU out of the
      scheduling pool, i.e. the WARN is intended to detect the case where the
      kernel attempts to schedule a task on an offline CPU.  The actual sending
      of the IPI is a non-issue as at worst it will simpy be dropped on the
      floor.  In other words, KVM's usurping of the reschedule IPI could
      theoretically trigger a WARN if the stars align, but there will be no
      loss of functionality.
      
      [*] https://syzkaller.appspot.com/bug?extid=cd4154e502f43f10808a
      
      Cc: Venkatesh Srinivas <venkateshs@google.com>
      Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
      Fixes: 97222cc8 ("KVM: Emulate local APIC in kernel")
      Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
      Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
      Message-Id: <20210827092516.1027264-2-vkuznets@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      85b64045
    • Vitaly Kuznetsov's avatar
      KVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect() · 2f9b68f5
      Vitaly Kuznetsov authored
      KASAN reports the following issue:
      
       BUG: KASAN: stack-out-of-bounds in kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
       Read of size 8 at addr ffffc9001364f638 by task qemu-kvm/4798
      
       CPU: 0 PID: 4798 Comm: qemu-kvm Tainted: G               X --------- ---
       Hardware name: AMD Corporation DAYTONA_X/DAYTONA_X, BIOS RYM0081C 07/13/2020
       Call Trace:
        dump_stack+0xa5/0xe6
        print_address_description.constprop.0+0x18/0x130
        ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
        __kasan_report.cold+0x7f/0x114
        ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
        kasan_report+0x38/0x50
        kasan_check_range+0xf5/0x1d0
        kvm_make_vcpus_request_mask+0x174/0x440 [kvm]
        kvm_make_scan_ioapic_request_mask+0x84/0xc0 [kvm]
        ? kvm_arch_exit+0x110/0x110 [kvm]
        ? sched_clock+0x5/0x10
        ioapic_write_indirect+0x59f/0x9e0 [kvm]
        ? static_obj+0xc0/0xc0
        ? __lock_acquired+0x1d2/0x8c0
        ? kvm_ioapic_eoi_inject_work+0x120/0x120 [kvm]
      
      The problem appears to be that 'vcpu_bitmap' is allocated as a single long
      on stack and it should really be KVM_MAX_VCPUS long. We also seem to clear
      the lower 16 bits of it with bitmap_zero() for no particular reason (my
      guess would be that 'bitmap' and 'vcpu_bitmap' variables in
      kvm_bitmap_or_dest_vcpus() caused the confusion: while the later is indeed
      16-bit long, the later should accommodate all possible vCPUs).
      
      Fixes: 7ee30bc1 ("KVM: x86: deliver KVM IOAPIC scan request to target vCPUs")
      Fixes: 9a2ae9f6 ("KVM: x86: Zero the IOAPIC scan request dest vCPUs bitmap")
      Reported-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
      Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
      Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
      Message-Id: <20210827092516.1027264-7-vkuznets@redhat.com>
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      2f9b68f5
    • David Matlack's avatar
      KVM: selftests: Create a separate dirty bitmap per slot · 7c236b81
      David Matlack authored
      The calculation to get the per-slot dirty bitmap was incorrect leading
      to a buffer overrun. Fix it by splitting out the dirty bitmap into a
      separate bitmap per slot.
      
      Fixes: 609e6202 ("KVM: selftests: Support multiple slots in dirty_log_perf_test")
      Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
      Reviewed-by: default avatarAndrew Jones <drjones@redhat.com>
      Message-Id: <20210917173657.44011-4-dmatlack@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      7c236b81
    • David Matlack's avatar
      KVM: selftests: Refactor help message for -s backing_src · 9f2fc555
      David Matlack authored
      All selftests that support the backing_src option were printing their
      own description of the flag and then calling backing_src_help() to dump
      the list of available backing sources. Consolidate the flag printing in
      backing_src_help() to align indentation, reduce duplicated strings, and
      improve consistency across tests.
      
      Note: Passing "-s" to backing_src_help is unnecessary since every test
      uses the same flag. However I decided to keep it for code readability
      at the call sites.
      
      While here this opportunistically fixes the incorrectly interleaved
      printing -x help message and list of backing source types in
      dirty_log_perf_test.
      
      Fixes: 609e6202 ("KVM: selftests: Support multiple slots in dirty_log_perf_test")
      Reviewed-by: default avatarBen Gardon <bgardon@google.com>
      Reviewed-by: default avatarAndrew Jones <drjones@redhat.com>
      Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
      Message-Id: <20210917173657.44011-3-dmatlack@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      9f2fc555
    • David Matlack's avatar
      KVM: selftests: Change backing_src flag to -s in demand_paging_test · a1e638da
      David Matlack authored
      Every other KVM selftest uses -s for the backing_src, so switch
      demand_paging_test to match.
      Reviewed-by: default avatarBen Gardon <bgardon@google.com>
      Reviewed-by: default avatarAndrew Jones <drjones@redhat.com>
      Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
      Message-Id: <20210917173657.44011-2-dmatlack@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      a1e638da
    • Peter Gonda's avatar
      KVM: SEV: Allow some commands for mirror VM · 5b92b6ca
      Peter Gonda authored
      A mirrored SEV-ES VM will need to call KVM_SEV_LAUNCH_UPDATE_VMSA to
      setup its vCPUs and have them measured, and their VMSAs encrypted. Without
      this change, it is impossible to have mirror VMs as part of SEV-ES VMs.
      
      Also allow the guest status check and debugging commands since they do
      not change any guest state.
      Signed-off-by: default avatarPeter Gonda <pgonda@google.com>
      Cc: Marc Orr <marcorr@google.com>
      Cc: Nathan Tempelman <natet@google.com>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Sean Christopherson <seanjc@google.com>
      Cc: Steve Rutherford <srutherford@google.com>
      Cc: Brijesh Singh <brijesh.singh@amd.com>
      Cc: kvm@vger.kernel.org
      Cc: linux-kernel@vger.kernel.org
      Cc: stable@vger.kernel.org
      Fixes: 54526d1f ("KVM: x86: Support KVM VMs sharing SEV context", 2021-04-21)
      Message-Id: <20210921150345.2221634-3-pgonda@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      5b92b6ca
    • Peter Gonda's avatar
      KVM: SEV: Update svm_vm_copy_asid_from for SEV-ES · f43c887c
      Peter Gonda authored
      For mirroring SEV-ES the mirror VM will need more then just the ASID.
      The FD and the handle are required to all the mirror to call psp
      commands. The mirror VM will need to call KVM_SEV_LAUNCH_UPDATE_VMSA to
      setup its vCPUs' VMSAs for SEV-ES.
      Signed-off-by: default avatarPeter Gonda <pgonda@google.com>
      Cc: Marc Orr <marcorr@google.com>
      Cc: Nathan Tempelman <natet@google.com>
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Sean Christopherson <seanjc@google.com>
      Cc: Steve Rutherford <srutherford@google.com>
      Cc: Brijesh Singh <brijesh.singh@amd.com>
      Cc: kvm@vger.kernel.org
      Cc: linux-kernel@vger.kernel.org
      Cc: stable@vger.kernel.org
      Fixes: 54526d1f ("KVM: x86: Support KVM VMs sharing SEV context", 2021-04-21)
      Message-Id: <20210921150345.2221634-2-pgonda@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      f43c887c
    • Chenyi Qiang's avatar
      KVM: nVMX: Fix nested bus lock VM exit · 24a996ad
      Chenyi Qiang authored
      Nested bus lock VM exits are not supported yet. If L2 triggers bus lock
      VM exit, it will be directed to L1 VMM, which would cause unexpected
      behavior. Therefore, handle L2's bus lock VM exits in L0 directly.
      
      Fixes: fe6b6bc8 ("KVM: VMX: Enable bus lock VM exit")
      Signed-off-by: default avatarChenyi Qiang <chenyi.qiang@intel.com>
      Reviewed-by: default avatarSean Christopherson <seanjc@google.com>
      Reviewed-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
      Message-Id: <20210914095041.29764-1-chenyi.qiang@intel.com>
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      24a996ad
    • Sean Christopherson's avatar
      KVM: x86: Identify vCPU0 by its vcpu_idx instead of its vCPUs array entry · 94c245a2
      Sean Christopherson authored
      Use vcpu_idx to identify vCPU0 when updating HyperV's TSC page, which is
      shared by all vCPUs and "owned" by vCPU0 (because vCPU0 is the only vCPU
      that's guaranteed to exist).  Using kvm_get_vcpu() to find vCPU works,
      but it's a rather odd and suboptimal method to check the index of a given
      vCPU.
      
      No functional change intended.
      Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
      Reviewed-by: default avatarJim Mattson <jmattson@google.com>
      Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
      Reviewed-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
      Message-Id: <20210910183220.2397812-3-seanjc@google.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      94c245a2