linux-toradex.git/virt, branch v4.8-rc6

Merge tag 'kvm-arm-for-v4.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

2016-08-18T10:19:19+00:00

KVM/ARM Fixes for v4.8-rc3

This tag contains the following fixes on top of v4.8-rc1:
 - ITS init issues
 - ITS error handling issues
 - ITS IRQ leakage fix
 - Plug a couple of ITS race conditions
 - An erratum workaround for timers
 - Some removal of misleading use of errors and comments
 - A fix for GICv3 on 32-bit guests

KVM: arm/arm64: timer: Workaround misconfigured timer interrupt

2016-08-17T10:23:47+00:00

Similarily to f005bd7e3b84 ("clocksource/arm_arch_timer: Force
per-CPU interrupt to be level-triggered"), make sure we can
survive an interrupt that has been misconfigured as edge-triggered
by forcing it to be level-triggered (active low is assumed, but
the GIC doesn't really care whether this is high or low).

Hopefully, the amount of shouting in the kernel log will convince
the user to do something about their firmware.

Signed-off-by: Marc Zyngier 
Signed-off-by: Christoffer Dall

KVM: arm64: ITS: avoid re-mapping LPIs

2016-08-16T17:27:22+00:00

When a guest wants to map a device-ID/event-ID combination that is
already mapped, we may end up in a situation where an LPI is never
"put", thus never being freed.
Since the GICv3 spec says that mapping an already mapped LPI is
UNPREDICTABLE, lets just bail out early in this situation to avoid
any potential leaks.

Signed-off-by: Andre Przywara 
Reviewed-by: Christoffer Dall 
Signed-off-by: Christoffer Dall

KVM: arm64: check for ITS device on MSI injection

2016-08-15T21:00:22+00:00

When userspace provides the doorbell address for an MSI to be
injected into the guest, we find a KVM device which feels responsible.
Lets check that this device is really an emulated ITS before we make
real use of the container_of-ed pointer.

  [ Moved NULL-pointer check to caller of static function
    - Christoffer ]

Signed-off-by: Andre Przywara 
Reviewed-by: Christoffer Dall 
Signed-off-by: Christoffer Dall

KVM: arm64: ITS: move ITS registration into first VCPU run

2016-08-15T21:00:21+00:00

Currently we register an ITS device upon userland issuing the CTLR_INIT
ioctl to mark initialization of the ITS as done.
This deviates from the initialization sequence of the existing GIC
devices and does not play well with the way QEMU handles things.
To be more in line with what we are used to, register the ITS(es) just
before the first VCPU is about to run, so in the map_resources() call.
This involves iterating through the list of KVM devices and map each
ITS that we find.

Signed-off-by: Andre Przywara 
Reviewed-by: Eric Auger 
Tested-by: Eric Auger 
Signed-off-by: Christoffer Dall

KVM: arm64: vgic-its: Make updates to propbaser/pendbaser atomic

2016-08-15T21:00:20+00:00

There are two problems with the current implementation of the MMIO
handlers for the propbaser and pendbaser:

First, the write to the value itself is not guaranteed to be an atomic
64-bit write so two concurrent writes to the structure field could be
intermixed.

Second, because we do a read-modify-update operation without any
synchronization, if we have two 32-bit accesses to separate parts of the
register, we can loose one of them.

By using the atomic cmpxchg64 we should cover both issues above.

Reviewed-by: Andre Przywara 
Signed-off-by: Christoffer Dall

KVM: Protect device ops->create and list_add with kvm->lock

2016-08-12T10:01:27+00:00

KVM devices were manipulating list data structures without any form of
synchronization, and some implementations of the create operations also
suffered from a lack of synchronization.

Now when we've split the xics create operation into create and init, we
can hold the kvm->lock mutex while calling the create operation and when
manipulating the devices list.

The error path in the generic code gets slightly ugly because we have to
take the mutex again and delete the device from the list, but holding
the mutex during anon_inode_getfd or releasing/locking the mutex in the
common non-error path seemed wrong.

Signed-off-by: Christoffer Dall 
Reviewed-by: Paolo Bonzini 
Acked-by: Christian Borntraeger 
Signed-off-by: Radim Krčmář

KVM: PPC: Move xics_debugfs_init out of create

2016-08-12T10:01:26+00:00

As we are about to hold the kvm->lock during the create operation on KVM
devices, we should move the call to xics_debugfs_init into its own
function, since holding a mutex over extended amounts of time might not
be a good idea.

Introduce an init operation on the kvm_device_ops struct which cannot
fail and call this, if configured, after the device has been created.

Signed-off-by: Christoffer Dall 
Reviewed-by: Paolo Bonzini 
Signed-off-by: Radim Krčmář

KVM: arm64: vgic-its: Plug race in vgic_put_irq

2016-08-10T09:41:54+00:00

Right now the following sequence of events can happen:

  1. Thread X calls vgic_put_irq
  2. Thread Y calls vgic_add_lpi
  3. Thread Y gets lpi_list_lock
  4. Thread X drops the ref count to 0 and blocks on lpi_list_lock
  5. Thread Y finds the irq via the lpi_list_lock, raises the ref
     count to 1, and release the lpi_list_lock.
  6. Thread X proceeds and frees the irq.

Avoid this by holding the spinlock around the kref_put.

Reviewed-by: Andre Przywara 
Signed-off-by: Christoffer Dall

KVM: arm64: vgic-its: Handle errors from vgic_add_lpi

2016-08-10T09:41:35+00:00

During low memory conditions, we could be dereferencing a NULL pointer
when vgic_add_lpi fails to allocate memory.

Consider for example this call sequence:

  vgic_its_cmd_handle_mapi
      itte->irq = vgic_add_lpi(kvm, lpi_nr);
          update_lpi_config(kvm, itte->irq, NULL);
              ret = kvm_read_guest(kvm, propbase + irq->intid
	                                             ^^^^
						     kaboom?

Instead, return an error pointer from vgic_add_lpi and check the return
value from its single caller.

Signed-off-by: Christoffer Dall