linux-toradex.git/virt/kvm/arm, branch v4.10

KVM: arm/arm64: vgic: Fix deadlock on error handling

2017-01-13T11:19:35+00:00

Dmitry Vyukov reported that the syzkaller fuzzer triggered a
deadlock in the vgic setup code when an error was detected, as
the cleanup code tries to take a lock that is already held by
the setup code.

The fix is to avoid retaking the lock when cleaning up, by
telling the cleanup function that we already hold it.

Cc: stable@vger.kernel.org
Reported-by: Dmitry Vyukov 
Reviewed-by: Christoffer Dall 
Reviewed-by: Eric Auger 
Signed-off-by: Marc Zyngier

KVM: arm64: Access CNTHCTL_EL2 bit fields correctly on VHE systems

2017-01-13T11:19:25+00:00

Current KVM world switch code is unintentionally setting wrong bits to
CNTHCTL_EL2 when E2H == 1, which may allow guest OS to access physical
timer.  Bit positions of CNTHCTL_EL2 are changing depending on
HCR_EL2.E2H bit.  EL1PCEN and EL1PCTEN are 1st and 0th bits when E2H is
not set, but they are 11th and 10th bits respectively when E2H is set.

In fact, on VHE we only need to set those bits once, not for every world
switch. This is because the host kernel runs in EL2 with HCR_EL2.TGE ==
1, which makes those bits have no effect for the host kernel execution.
So we just set those bits once for guests, and that's it.

Signed-off-by: Jintack Lim 
Reviewed-by: Marc Zyngier 
Signed-off-by: Marc Zyngier

KVM: arm/arm64: Fix occasional warning from the timer work function

2017-01-13T11:15:30+00:00

When a VCPU blocks (WFI) and has programmed the vtimer, we program a
soft timer to expire in the future to wake up the vcpu thread when
appropriate.  Because such as wake up involves a vcpu kick, and the
timer expire function can get called from interrupt context, and the
kick may sleep, we have to schedule the kick in the work function.

The work function currently has a warning that gets raised if it turns
out that the timer shouldn't fire when it's run, which was added because
the idea was that in that case the work should never have been cancelled.

However, it turns out that this whole thing is racy and we can get
spurious warnings.  The problem is that we clear the armed flag in the
work function, which may run in parallel with the
kvm_timer_unschedule->timer_disarm() call.  This results in a possible
situation where the timer_disarm() call does not call
cancel_work_sync(), which effectively synchronizes the completion of the
work function with running the VCPU.  As a result, the VCPU thread
proceeds before the work function completees, causing changes to the
timer state such that kvm_timer_should_fire(vcpu) returns false in the
work function.

All we do in the work function is to kick the VCPU, and an occasional
rare extra kick never harmed anyone.  Since the race above is extremely
rare, we don't bother checking if the race happens but simply remove the
check and the clearing of the armed flag from the work function.

Reported-by: Matthias Brugger 
Reviewed-by: Marc Zyngier 
Signed-off-by: Christoffer Dall 
Signed-off-by: Marc Zyngier

Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-12-25T22:30:04+00:00

Pull timer type cleanups from Thomas Gleixner:
 "This series does a tree wide cleanup of types related to
  timers/timekeeping.

   - Get rid of cycles_t and use a plain u64. The type is not really
     helpful and caused more confusion than clarity

   - Get rid of the ktime union. The union has become useless as we use
     the scalar nanoseconds storage unconditionally now. The 32bit
     timespec alike storage got removed due to the Y2038 limitations
     some time ago.

     That leaves the odd union access around for no reason. Clean it up.

  Both changes have been done with coccinelle and a small amount of
  manual mopping up"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ktime: Get rid of ktime_equal()
  ktime: Cleanup ktime_set() usage
  ktime: Get rid of the union
  clocksource: Use a plain u64 instead of cycle_t

clocksource: Use a plain u64 instead of cycle_t

2016-12-25T10:04:12+00:00

There is no point in having an extra type for extra confusion. u64 is
unambiguous.

Conversion was done with the following coccinelle script:

@rem@
@@
-typedef u64 cycle_t;

@fix@
typedef cycle_t;
@@
-cycle_t
+u64

Signed-off-by: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: John Stultz

cpu/hotplug: Cleanup state names

2016-12-25T09:47:44+00:00

When the state names got added a script was used to add the extra argument
to the calls. The script basically converted the state constant to a
string, but the cleanup to convert these strings into meaningful ones did
not happen.

Replace all the useless strings with 'subsys/xxx/yyy:state' strings which
are used in all the other places already.

Signed-off-by: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: Sebastian Siewior 
Link: http://lkml.kernel.org/r/20161221192112.085444152@linutronix.de
Signed-off-by: Thomas Gleixner

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2016-12-13T23:47:02+00:00

Pull KVM updates from Paolo Bonzini:
 "Small release, the most interesting stuff is x86 nested virt
  improvements.

  x86:
   - userspace can now hide nested VMX features from guests
   - nested VMX can now run Hyper-V in a guest
   - support for AVX512_4VNNIW and AVX512_FMAPS in KVM
   - infrastructure support for virtual Intel GPUs.

  PPC:
   - support for KVM guests on POWER9
   - improved support for interrupt polling
   - optimizations and cleanups.

  s390:
   - two small optimizations, more stuff is in flight and will be in
     4.11.

  ARM:
   - support for the GICv3 ITS on 32bit platforms"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (94 commits)
  arm64: KVM: pmu: Reset PMSELR_EL0.SEL to a sane value before entering the guest
  KVM: arm/arm64: timer: Check for properly initialized timer on init
  KVM: arm/arm64: vgic-v2: Limit ITARGETSR bits to number of VCPUs
  KVM: x86: Handle the kthread worker using the new API
  KVM: nVMX: invvpid handling improvements
  KVM: nVMX: check host CR3 on vmentry and vmexit
  KVM: nVMX: introduce nested_vmx_load_cr3 and call it on vmentry
  KVM: nVMX: propagate errors from prepare_vmcs02
  KVM: nVMX: fix CR3 load if L2 uses PAE paging and EPT
  KVM: nVMX: load GUEST_EFER after GUEST_CR0 during emulated VM-entry
  KVM: nVMX: generate MSR_IA32_CR{0,4}_FIXED1 from guest CPUID
  KVM: nVMX: fix checks on CR{0,4} during virtual VMX operation
  KVM: nVMX: support restore of VMX capability MSRs
  KVM: nVMX: generate non-true VMX MSRs based on true versions
  KVM: x86: Do not clear RFLAGS.TF when a singlestep trap occurs.
  KVM: x86: Add kvm_skip_emulated_instruction and use it.
  KVM: VMX: Move skip_emulated_instruction out of nested_vmx_check_vmcs12
  KVM: VMX: Reorder some skip_emulated_instruction calls
  KVM: x86: Add a return value to kvm_emulate_cpuid
  KVM: PPC: Book3S: Move prototypes for KVM functions into kvm_ppc.h
  ...

KVM: arm/arm64: timer: Check for properly initialized timer on init

2016-12-09T15:47:00+00:00

When the arch timer code fails to initialize (for example because the
memory mapped timer doesn't work, which is currently seen with the AEM
model), then KVM just continues happily with a final result that KVM
eventually does a NULL pointer dereference of the uninitialized cycle
counter.

Check directly for this in the init path and give the user a reasonable
error in this case.

Cc: Shih-Wei Li 
Signed-off-by: Christoffer Dall 
Signed-off-by: Marc Zyngier

KVM: arm/arm64: vgic-v2: Limit ITARGETSR bits to number of VCPUs

2016-12-09T15:46:59+00:00

The GICv2 spec says in section 4.3.12 that a "CPU targets field bit that
corresponds to an unimplemented CPU interface is RAZ/WI."
Currently we allow the guest to write any value in there and it can
read that back.
Mask the written value with the proper CPU mask to be spec compliant.

Signed-off-by: Andre Przywara 
Signed-off-by: Marc Zyngier

KVM: arm/arm64: vgic: Don't notify EOI for non-SPIs

2016-11-24T13:12:07+00:00

When we inject a level triggerered interrupt (and unless it
is backed by the physical distributor - timer style), we request
a maintenance interrupt. Part of the processing for that interrupt
is to feed to the rest of KVM (and to the eventfd subsystem) the
information that the interrupt has been EOIed.

But that notification only makes sense for SPIs, and not PPIs
(such as the PMU interrupt). Skip over the notification if
the interrupt is not an SPI.

Cc: stable@vger.kernel.org # 4.7+
Fixes: 140b086dd197 ("KVM: arm/arm64: vgic-new: Add GICv2 world switch backend")
Fixes: 59529f69f504 ("KVM: arm/arm64: vgic-new: Add GICv3 world switch backend")
Reported-by: Catalin Marinas 
Tested-by: Catalin Marinas 
Acked-by: Christoffer Dall 
Signed-off-by: Marc Zyngier