1. 28 Mar, 2018 25 commits
  2. 26 Mar, 2018 2 commits
    • Marc Zyngier's avatar
      KVM: arm/arm64: vgic-its: Fix potential overrun in vgic_copy_lpi_list · 7d8b44c5
      Marc Zyngier authored
      vgic_copy_lpi_list() parses the LPI list and picks LPIs targeting
      a given vcpu. We allocate the array containing the intids before taking
      the lpi_list_lock, which means we can have an array size that is not
      equal to the number of LPIs.
      
      This is particularly obvious when looking at the path coming from
      vgic_enable_lpis, which is not a command, and thus can run in parallel
      with commands:
      
      vcpu 0:                                        vcpu 1:
      vgic_enable_lpis
        its_sync_lpi_pending_table
          vgic_copy_lpi_list
            intids = kmalloc_array(irq_count)
                                                     MAPI(lpi targeting vcpu 0)
            list_for_each_entry(lpi_list_head)
              intids[i++] = irq->intid;
      
      At that stage, we will happily overrun the intids array. Boo. An easy
      fix is is to break once the array is full. The MAPI command will update
      the config anyway, and we won't miss a thing. We also make sure that
      lpi_list_count is read exactly once, so that further updates of that
      value will not affect the array bound check.
      
      Cc: stable@vger.kernel.org
      Fixes: ccb1d791 ("KVM: arm64: vgic-its: Fix pending table sync")
      Reviewed-by: default avatarAndre Przywara <andre.przywara@arm.com>
      Reviewed-by: default avatarEric Auger <eric.auger@redhat.com>
      Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
      7d8b44c5
    • Marc Zyngier's avatar
      KVM: arm/arm64: vgic: Disallow Active+Pending for level interrupts · 67b5b673
      Marc Zyngier authored
      It was recently reported that VFIO mediated devices, and anything
      that VFIO exposes as level interrupts, do no strictly follow the
      expected logic of such interrupts as it only lowers the input
      line when the guest has EOId the interrupt at the GIC level, rather
      than when it Acked the interrupt at the device level.
      
      THe GIC's Active+Pending state is fundamentally incompatible with
      this behaviour, as it prevents KVM from observing the EOI, and in
      turn results in VFIO never dropping the line. This results in an
      interrupt storm in the guest, which it really never expected.
      
      As we cannot really change VFIO to follow the strict rules of level
      signalling, let's forbid the A+P state altogether, as it is in the
      end only an optimization. It ensures that we will transition via
      an invalid state, which we can use to notify VFIO of the EOI.
      Reviewed-by: default avatarEric Auger <eric.auger@redhat.com>
      Tested-by: default avatarEric Auger <eric.auger@redhat.com>
      Tested-by: default avatarShunyong Yang <shunyong.yang@hxt-semitech.com>
      Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
      67b5b673
  3. 23 Mar, 2018 5 commits
  4. 21 Mar, 2018 2 commits
    • Paolo Bonzini's avatar
      KVM: nVMX: fix vmentry failure code when L2 state would require emulation · 3184a995
      Paolo Bonzini authored
      Commit 2bb8cafe ("KVM: vVMX: signal failure for nested VMEntry if
      emulation_required", 2018-03-12) introduces a new error path which does
      not set *entry_failure_code.  Fix that to avoid a leak of L0 stack to L1.
      Reported-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
      Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      3184a995
    • Liran Alon's avatar
      KVM: nVMX: Do not load EOI-exitmap while running L2 · e40ff1d6
      Liran Alon authored
      When L1 IOAPIC redirection-table is written, a request of
      KVM_REQ_SCAN_IOAPIC is set on all vCPUs. This is done such that
      all vCPUs will now recalc their IOAPIC handled vectors and load
      it to their EOI-exitmap.
      
      However, it could be that one of the vCPUs is currently running
      L2. In this case, load_eoi_exitmap() will be called which would
      write to vmcs02->eoi_exit_bitmap, which is wrong because
      vmcs02->eoi_exit_bitmap should always be equal to
      vmcs12->eoi_exit_bitmap. Furthermore, at this point
      KVM_REQ_SCAN_IOAPIC was already consumed and therefore we will
      never update vmcs01->eoi_exit_bitmap. This could lead to remote_irr
      of some IOAPIC level-triggered entry to remain set forever.
      
      Fix this issue by delaying the load of EOI-exitmap to when vCPU
      is running L1.
      
      One may wonder why not just delay entire KVM_REQ_SCAN_IOAPIC
      processing to when vCPU is running L1. This is done in order to handle
      correctly the case where LAPIC & IO-APIC of L1 is pass-throughed into
      L2. In this case, vmcs12->virtual_interrupt_delivery should be 0. In
      current nVMX implementation, that results in
      vmcs02->virtual_interrupt_delivery to also be 0. Thus,
      vmcs02->eoi_exit_bitmap is not used. Therefore, every L2 EOI cause
      a #VMExit into L0 (either on MSR_WRITE to x2APIC MSR or
      APIC_ACCESS/APIC_WRITE/EPT_MISCONFIG to APIC MMIO page).
      In order for such L2 EOI to be broadcasted, if needed, from LAPIC
      to IO-APIC, vcpu->arch.ioapic_handled_vectors must be updated
      while L2 is running. Therefore, patch makes sure to delay only the
      loading of EOI-exitmap but not the update of
      vcpu->arch.ioapic_handled_vectors.
      Reviewed-by: default avatarArbel Moshe <arbel.moshe@oracle.com>
      Reviewed-by: default avatarKrish Sadhukhan <krish.sadhukhan@oracle.com>
      Signed-off-by: default avatarLiran Alon <liran.alon@oracle.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      e40ff1d6
  5. 19 Mar, 2018 6 commits