1. 12 Jul, 2017 34 commits
  2. 05 Jul, 2017 6 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.9.36 · 9f86f302
      Greg Kroah-Hartman authored
      9f86f302
    • Wanpeng Li's avatar
      KVM: nVMX: Fix exception injection · a29fd27c
      Wanpeng Li authored
      commit d4912215 upstream.
      
       WARNING: CPU: 3 PID: 2840 at arch/x86/kvm/vmx.c:10966 nested_vmx_vmexit+0xdcd/0xde0 [kvm_intel]
       CPU: 3 PID: 2840 Comm: qemu-system-x86 Tainted: G           OE   4.12.0-rc3+ #23
       RIP: 0010:nested_vmx_vmexit+0xdcd/0xde0 [kvm_intel]
       Call Trace:
        ? kvm_check_async_pf_completion+0xef/0x120 [kvm]
        ? rcu_read_lock_sched_held+0x79/0x80
        vmx_queue_exception+0x104/0x160 [kvm_intel]
        ? vmx_queue_exception+0x104/0x160 [kvm_intel]
        kvm_arch_vcpu_ioctl_run+0x1171/0x1ce0 [kvm]
        ? kvm_arch_vcpu_load+0x47/0x240 [kvm]
        ? kvm_arch_vcpu_load+0x62/0x240 [kvm]
        kvm_vcpu_ioctl+0x384/0x7b0 [kvm]
        ? kvm_vcpu_ioctl+0x384/0x7b0 [kvm]
        ? __fget+0xf3/0x210
        do_vfs_ioctl+0xa4/0x700
        ? __fget+0x114/0x210
        SyS_ioctl+0x79/0x90
        do_syscall_64+0x81/0x220
        entry_SYSCALL64_slow_path+0x25/0x25
      
      This is triggered occasionally by running both win7 and win2016 in L2, in
      addition, EPT is disabled on both L1 and L2. It can't be reproduced easily.
      
      Commit 0b6ac343 (KVM: nVMX: Correct handling of exception injection) mentioned
      that "KVM wants to inject page-faults which it got to the guest. This function
      assumes it is called with the exit reason in vmcs02 being a #PF exception".
      Commit e011c663 (KVM: nVMX: Check all exceptions for intercept during delivery to
      L2) allows to check all exceptions for intercept during delivery to L2. However,
      there is no guarantee the exit reason is exception currently, when there is an
      external interrupt occurred on host, maybe a time interrupt for host which should
      not be injected to guest, and somewhere queues an exception, then the function
      nested_vmx_check_exception() will be called and the vmexit emulation codes will
      try to emulate the "Acknowledge interrupt on exit" behavior, the warning is
      triggered.
      
      Reusing the exit reason from the L2->L0 vmexit is wrong in this case,
      the reason must always be EXCEPTION_NMI when injecting an exception into
      L1 as a nested vmexit.
      
      Cc: Paolo Bonzini <pbonzini@redhat.com>
      Cc: Radim Krčmář <rkrcmar@redhat.com>
      Signed-off-by: default avatarWanpeng Li <wanpeng.li@hotmail.com>
      Fixes: e011c663 ("KVM: nVMX: Check all exceptions for intercept during delivery to L2")
      Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a29fd27c
    • Radim Krčmář's avatar
      KVM: x86: zero base3 of unusable segments · d1d3756f
      Radim Krčmář authored
      commit f0367ee1 upstream.
      
      Static checker noticed that base3 could be used uninitialized if the
      segment was not present (useable).  Random stack values probably would
      not pass VMCS entry checks.
      Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
      Fixes: 1aa36616 ("KVM: x86 emulator: consolidate segment accessors")
      Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
      Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      d1d3756f
    • Radim Krčmář's avatar
      KVM: x86/vPMU: fix undefined shift in intel_pmu_refresh() · f3c3ec96
      Radim Krčmář authored
      commit 34b0dadb upstream.
      
      Static analysis noticed that pmu->nr_arch_gp_counters can be 32
      (INTEL_PMC_MAX_GENERIC) and therefore cannot be used to shift 'int'.
      
      I didn't add BUILD_BUG_ON for it as we have a better checker.
      Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
      Fixes: 25462f7f ("KVM: x86/vPMU: Define kvm_pmu_ops to support vPMU function dispatch")
      Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
      Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f3c3ec96
    • Ladi Prosek's avatar
      KVM: x86: fix emulation of RSM and IRET instructions · 1eeb7942
      Ladi Prosek authored
      commit 6ed071f0 upstream.
      
      On AMD, the effect of set_nmi_mask called by emulate_iret_real and em_rsm
      on hflags is reverted later on in x86_emulate_instruction where hflags are
      overwritten with ctxt->emul_flags (the kvm_set_hflags call). This manifests
      as a hang when rebooting Windows VMs with QEMU, OVMF, and >1 vcpu.
      
      Instead of trying to merge ctxt->emul_flags into vcpu->arch.hflags after
      an instruction is emulated, this commit deletes emul_flags altogether and
      makes the emulator access vcpu->arch.hflags using two new accessors. This
      way all changes, on the emulator side as well as in functions called from
      the emulator and accessing vcpu state with emul_to_vcpu, are preserved.
      
      More details on the bug and its manifestation with Windows and OVMF:
      
        It's a KVM bug in the interaction between SMI/SMM and NMI, specific to AMD.
        I believe that the SMM part explains why we started seeing this only with
        OVMF.
      
        KVM masks and unmasks NMI when entering and leaving SMM. When KVM emulates
        the RSM instruction in em_rsm, the set_nmi_mask call doesn't stick because
        later on in x86_emulate_instruction we overwrite arch.hflags with
        ctxt->emul_flags, effectively reverting the effect of the set_nmi_mask call.
        The AMD-specific hflag of interest here is HF_NMI_MASK.
      
        When rebooting the system, Windows sends an NMI IPI to all but the current
        cpu to shut them down. Only after all of them are parked in HLT will the
        initiating cpu finish the restart. If NMI is masked, other cpus never get
        the memo and the initiating cpu spins forever, waiting for
        hal!HalpInterruptProcessorsStarted to drop. That's the symptom we observe.
      
      Fixes: a584539b ("KVM: x86: pass the whole hflags field to emulator and back")
      Signed-off-by: default avatarLadi Prosek <lprosek@redhat.com>
      Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      1eeb7942
    • Mark Salter's avatar
      arm64: fix NULL dereference in have_cpu_die() · 982d8d92
      Mark Salter authored
      commit 335d2c2d upstream.
      
      Commit 5c492c3f ("arm64: smp: Add function to determine if cpus are
      stuck in the kernel") added a helper function to determine if die() is
      supported in cpu_ops. This function assumes a cpu will have a valid
      cpu_ops entry, but that may not be the case for cpu0 is spin-table or
      parking protocol is used to boot secondary cpus. In that case, there
      is a NULL dereference if have_cpu_die() is called by cpu0. So add a
      check for a valid cpu_ops before dereferencing it.
      
      Fixes: 5c492c3f ("arm64: smp: Add function to determine if cpus are stuck in the kernel")
      Signed-off-by: default avatarMark Salter <msalter@redhat.com>
      Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      982d8d92