KVM: PPC: BookE: Add check_requests helper function

We need a central place to check for pending requests in. Add one that
only does the timer check we already do in a different place.

Later, this central function can be extended by more checks.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: BookE: Add support for vcpu->mode

Generic KVM code might want to know whether we are inside guest context
or outside. It also wants to be able to push us out of guest context.

Add support to the BookE code for the generic vcpu->mode field that describes
the above states.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: E500: Implement MMU notifiers

The e500 target has lived without mmu notifiers ever since it got
introduced, but fails for the user space check on them with hugetlbfs.

So in order to get that one working, implement mmu notifiers in a
reasonably dumb fashion and be happy. On embedded hardware, we almost
never end up with mmu notifier calls, since most people don't overcommit.

Signed-off-by: Alexander Graf <agraf@suse.de>

---

v1 -> v2:

  - drop refcount for in-use pages
  - mark pages dirty at mapping time, not unmapping time
  - drop hva_to_memslot usage
KVM: PPC: Add cache flush on page map

When we map a page that wasn't icache cleared before, do so when first
mapping it in KVM using the same information bits as the Linux mapping
logic. That way we are 100% sure that any page we map does not have stale
entries in the icache.

Signed-off-by: Alexander Graf <agraf@suse.de>

---

v1 -> v2:

  - move code to arch/powerpc
KVM: PPC: BookE: Add some more trace points

Without trace points, debugging what exactly is going on inside guest
code can be very tricky. Add a few more trace points at places that
hopefully tell us more when things go wrong.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: BookE: No duplicate request != 0 check

We only call kvmppc_check_requests() when vcpu->requests != 0, so drop
the redundant check in the function itself

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: Use same kvmppc_prepare_to_enter code for booke and book3s_pr

We need to do the same things when preparing to enter a guest for booke and
book3s_pr cores. Fold the generic code into a generic function that both call.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: Book3s: PR: Add (dumb) MMU Notifier support

Now that we have very simple MMU Notifier support for e500 in place,
also add the same simple support to book3s. It gets us one step closer
to actual fast support.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: BookE: Drop redundant vcpu->mode set

We only need to set vcpu->mode to outside once.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: Book3S: PR: Only do resched check once per exit

Now that we use our generic exit helper, we can safely drop our previous
kvm_resched that we used to trigger at the beginning of the exit handler
function.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: Exit guest context while handling exit

The x86 implementation of KVM accounts for host time while processing
guest exits. Do the same for us.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: Book3S: PR: Indicate we're out of guest mode

When going out of guest mode, indicate that we are in vcpu->mode. That way
requests from other CPUs don't needlessly need to kick us to process them,
because it'll just happen next time we enter the guest.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: Consistentify vcpu exit path

When getting out of __vcpu_run, let's be consistent about the state we
return in. We want to always

  * have IRQs enabled
  * have called kvm_guest_exit before

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: Book3S: PR: Rework irq disabling

Today, we disable preemption while inside guest context, because we need
to expose to the world that we are not in a preemptible context. However,
during that time we already have interrupts disabled, which would indicate
that we are in a non-preemptible context.

The reason the checks for irqs_disabled() fail for us though is that we
manually control hard IRQs and ignore all the lazy EE framework. Let's
stop doing that. Instead, let's always use lazy EE to indicate when we
want to disable IRQs, but do a special final switch that gets us into
EE disabled, but soft enabled state. That way when we get back out of
guest state, we are immediately ready to process interrupts.

This simplifies the code drastically and reduces the time that we appear
as preempt disabled.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: Move kvm_guest_enter call into generic code

We need to call kvm_guest_enter in booke and book3s, so move its
call to generic code.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: Ignore EXITING_GUEST_MODE mode

We don't need to do anything when mode is EXITING_GUEST_MODE, because
we essentially are outside of guest mode and did everything it asked
us to do by the time we check it.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: Add return value in prepare_to_enter

Our prepare_to_enter helper wants to be able to return in more circumstances
to the host than only when an interrupt is pending. Broaden the interface a
bit and move even more generic code to the generic helper.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: Add return value to core_check_requests

Requests may want to tell us that we need to go back into host state,
so add a return value for the checks.

Signed-off-by: Alexander Graf <agraf@suse.de>
KVM: PPC: booke: Add watchdog emulation

This patch adds the watchdog emulation in KVM. The watchdog
emulation is enabled by KVM_ENABLE_CAP(KVM_CAP_PPC_BOOKE_WATCHDOG) ioctl.
The kernel timer are used for watchdog emulation and emulates
h/w watchdog state machine. On watchdog timer expiry, it exit to QEMU
if TCR.WRC is non ZERO. QEMU can reset/shutdown etc depending upon how
it is configured.

Signed-off-by: Liu Yu <yu.liu@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
[bharat.bhushan@freescale.com: reworked patch]
Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
[agraf: adjust to new request framework]
Signed-off-by: Alexander Graf <agraf@suse.de>
booke: Added ONE_REG interface for IAC/DAC debug registers

IAC/DAC are defined as 32 bit while they are 64 bit wide. So ONE_REG
interface is added to set/get them.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>