linux.git/arch/arm/kvm, branch v4.12

arm: KVM: Allow unaligned accesses at HYP

2017-06-06T20:20:02+00:00

We currently have the HSCTLR.A bit set, trapping unaligned accesses
at HYP, but we're not really prepared to deal with it.

Since the rest of the kernel is pretty happy about that, let's follow
its example and set HSCTLR.A to zero. Modern CPUs don't really care.

Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier 
Signed-off-by: Christoffer Dall

KVM: arm: rename pm_fake handler to trap_raz_wi

2017-05-15T12:29:27+00:00

pm_fake doesn't quite describe what the handler does (ignoring writes
and returning 0 for reads).

As we're about to use it (a lot) in a different context, rename it
with a (admitedly cryptic) name that make sense for all users.

Signed-off-by: Zhichao Huang 
Reviewed-by: Alex Bennee 
Acked-by: Christoffer Dall 
Acked-by: Marc Zyngier 
Signed-off-by: Alex Bennée 
Signed-off-by: Christoffer Dall

KVM: arm: plug potential guest hardware debug leakage

2017-05-15T12:29:19+00:00

Hardware debugging in guests is not intercepted currently, it means
that a malicious guest can bring down the entire machine by writing
to the debug registers.

This patch enable trapping of all debug registers, preventing the
guests to access the debug registers. This includes access to the
debug mode(DBGDSCR) in the guest world all the time which could
otherwise mess with the host state. Reads return 0 and writes are
ignored (RAZ_WI).

The result is the guest cannot detect any working hardware based debug
support. As debug exceptions are still routed to the guest normal
debug using software based breakpoints still works.

To support debugging using hardware registers we need to implement a
debug register aware world switch as well as special trapping for
registers that may affect the host state.

Cc: stable@vger.kernel.org
Signed-off-by: Zhichao Huang 
Signed-off-by: Alex Bennée 
Reviewed-by: Christoffer Dall 
Signed-off-by: Christoffer Dall

arm: KVM: Do not use stack-protector to compile HYP code

2017-05-15T09:31:38+00:00

We like living dangerously. Nothing explicitely forbids stack-protector
to be used in the HYP code, while distributions routinely compile their
kernel with it. We're just lucky that no code actually triggers the
instrumentation.

Let's not try our luck for much longer, and disable stack-protector
for code living at HYP.

Cc: stable@vger.kernel.org
Signed-off-by: Marc Zyngier 
Acked-by: Christoffer Dall 
Signed-off-by: Christoffer Dall

ARM: KVM: Fix tracepoint generation after move to virt/kvm/arm/

2017-05-15T06:58:50+00:00

Moving most of the shared code to virt/kvm/arm had for consequence
that KVM/ARM doesn't build anymore, because the code that used to
define the tracepoints is now somewhere else.

Fix this by defining CREATE_TRACE_POINTS in coproc.c, and clean-up
trace.h as well.

Fixes: 35d2d5d490e2 ("KVM: arm/arm64: Move shared files to virt/kvm/arm")
Reported-by: Arnd Bergmann 
Signed-off-by: Marc Zyngier 
Signed-off-by: Christoffer Dall

KVM: arm/arm64: Move shared files to virt/kvm/arm

2017-05-04T11:57:26+00:00

For some time now we have been having a lot of shared functionality
between the arm and arm64 KVM support in arch/arm, which not only
required a horrible inter-arch reference from the Makefile in
arch/arm64/kvm, but also created confusion for newcomers to the code
base, as was recently seen on the mailing list.

Further, it causes confusion for things like cscope, which needs special
attention to index specific shared files for arm64 from the arm tree.

Move the shared files into virt/kvm/arm and move the trace points along
with it.  When moving the tracepoints we have to modify the way the vgic
creates definitions of the trace points, so we take the chance to
include the VGIC tracepoints in its very own special vgic trace.h file.

Signed-off-by: Christoffer Dall

ARM: KVM: Fix idmap stub entry when running Thumb-2 code

2017-04-20T18:17:57+00:00

When entering the hyp stub implemented in the idmap, we try to
be mindful of the fact that we could be running a Thumb-2 kernel
by adding 1 to the address we compute. Unfortunately, the assembler
also knows about this trick, and has already generated an address
that has bit 0 set in the litteral pool.

Our superfluous correction ends up confusing the CPU entierely,
as we now branch to the stub in ARM mode instead of Thumb, and on
a possibly unaligned address for good measure. From that point,
nothing really good happens.

The obvious fix in to remove this stupid target PC correction.

Fixes: 6bebcecb6c5b ("ARM: KVM: Allow the main HYP code to use the init hyp stub implementation")
Reported-by: Christoffer Dall 
Signed-off-by: Marc Zyngier 
Signed-off-by: Christoffer Dall

KVM: arm/arm64: fix races in kvm_psci_vcpu_on

2017-04-19T15:28:11+00:00

Fix potential races in kvm_psci_vcpu_on() by taking the kvm->lock
mutex.  In general, it's a bad idea to allow more than one PSCI_CPU_ON
to process the same target VCPU at the same time.  One such problem
that may arise is that one PSCI_CPU_ON could be resetting the target
vcpu, which fills the entire sys_regs array with a temporary value
including the MPIDR register, while another looks up the VCPU based
on the MPIDR value, resulting in no target VCPU found.  Resolves both
races found with the kvm-unit-tests/arm/psci unit test.

Reviewed-by: Marc Zyngier 
Reviewed-by: Christoffer Dall 
Reported-by: Levente Kurusa 
Suggested-by: Christoffer Dall 
Signed-off-by: Andrew Jones 
Cc: stable@vger.kernel.org
Signed-off-by: Christoffer Dall

KVM: arm/arm64: Advertise support for KVM_CAP_ARM_USER_IRQ

2017-04-09T14:49:40+00:00

Now that we support both timers and PMU reporting interrupts
to userspace, we can advertise this support.

Reviewed-by: Alexander Graf 
Reviewed-by: Marc Zyngier 
Signed-off-by: Christoffer Dall

KVM: arm/arm64: Report PMU overflow interrupts to userspace irqchip

2017-04-09T14:49:39+00:00

When not using an in-kernel VGIC, but instead emulating an interrupt
controller in userspace, we should report the PMU overflow status to
that userspace interrupt controller using the KVM_CAP_ARM_USER_IRQ
feature.

Reviewed-by: Alexander Graf 
Reviewed-by: Marc Zyngier 
Signed-off-by: Christoffer Dall