Currently the lowest "real" irq number for the XICS irq controller (as
opposed to numbers reserved for IPIs and other special purposes) is
hard coded as 16 in two places - in xics_system_init() and in spapr.c.

As well as being generally bad practice, we're going to need to change this
number soon to fit in with the in-kernel XICS implementation.  This patch
adds a #define for this number to avoid future breakage.
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: NBen Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Currently in the reset code for the XICS interrupt controller, we
initialize the pending_priority field to 0 (most favored, by XICS
convention).  This is incorrect, since there is no pending interrupt, it
should be set to least favored - 0xff.  At the moment our XICS
implementation doesn't get hurt by this edge case, but it does confuse the
upcoming kernel XICS implementation.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

A couple of places in xics.c open-coded the same logic as is already
implemented in ics_valid_irq().  This patch fixes the code duplication.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Throughout xics.c 'nr' is used to refer to a global interrupt number, and
'server' is used to refer to an interrupt server number (i.e. CPU number).
Except in icp_set_mfrr(), where 'nr' is used as a server number.  Fix this
confusing inconsistency.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Needed for changing cpu_has_work() argument type to CPUState,
used in h_cede().
Signed-off-by: NAndreas Färber <afaerber@suse.de>

Currently the ibm,int-on and ibm,int-off RTAS functions are implemented as
no-ops.  This is because when implemented as specified in PAPR they caused
Linux (which calls both int-on/off and set-xive) to end up with interrupts
masked when they should not be.  Since Linux's set-xive calls make the
int-on/off calls redundant, making them nops worked around the problem.

In fact, the problem was caused because there was a subtle bug in set-xive,
PAPR specifies that as well as updating the current priority, it also needs
to update the saved priority used by int-on/off.  With this bug fixed the
problem goes away.  This patch implements this more correct fix.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Currently the XICS interrupt controller emulation uses a custom enum to
specify whether a given interrupt is level-sensitive or message-triggered.
This enum makes life awkward for saving the state, and isn't particularly
useful since there are only two possibilities.  This patch replaces the
enum with a simple bool.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

The XICS interrupt controller emulation uses some C bitfield variables in
its internal state structure.  This makes like awkward for saving the state
because we don't have easy VMSTATE helpers for bitfields.

This patch removes the bitfields, instead using explicit bit masking in a
single status variable.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

The XICS interrupt controller used on the pseries machine currently has no
reset handler.  We can get away with this under some circumstances, but
it's not correct, and can cause failures if the XICS happens to be in the
wrong state at the time of reset.

This patch adds a hook to properly reset the XICS state.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Currently, the interfaces in the pseries machine code for assignment
and setup of interrupts pass around qemu_irq objects.  That was done
in an attempt not to be too closely linked to the specific XICS
interrupt controller.  However interactions with the device tree setup
made that attempt rather futile, and XICS is part of the PAPR spec
anyway, so this really just meant we had to carry both the qemu_irq
pointers and the XICS irq numbers around.

This mess will just get worse when we add upcoming PCI MSI support,
since that will require tracking a bunch more interrupt.  Therefore,
this patch reworks the spapr code to just use XICS irq numbers
(roughly equivalent to GSIs on x86) and only retrieve the qemu_irq
pointers from the XICS code when we need them (a trivial lookup).

This is a reworked and generalized version of an earlier spapr_pci
specific patch from Alexey Kardashevskiy.
Signed-off-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
[agraf: fix checkpath warning]
Signed-off-by: NAlexander Graf <agraf@suse.de>

The pseries "xics" interrupt controller, like most interrupt
controllers can support both message (i.e. edge sensitive) interrupts
and level sensitive interrupts, but it needs to know which are which.

When I implemented the xics emulation for qemu, the only devices we
supported were the PAPR virtual IO devices.  These devices only use
message interrupts, so they were the only ones I implemented in xics.

Since then, however, we have added support for PCI devices, which use
level sensitive interrupts.  It turns out the message interrupt logic
still actually works most of the time for these, but there are
circumstances where we can lost interrupts due to the incorrect
interrupt logic.

This patch, therefore, implements the correct xics level-sensitive
interrupt logic.  The type of the interrupt is set when a device
allocates a new xics interrupt.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Scripted conversion:
  for file in hw/ppc*.[hc] hw/mpc8544_guts.c hw/spapr*.[hc] hw/virtex_ml507.c hw/xics.c; do
    sed -i "s/CPUState/CPUPPCState/g" $file
  done
Signed-off-by: NAndreas Färber <afaerber@suse.de>
Acked-by: NAnthony Liguori <aliguori@us.ibm.com>

The implementation of the XICS interrupt controller contains several
(difficult to trigger) bugs due to the fact that we were not 100%
consistent with which irq numbering we used.  In most places, global
numbers were used as handled by the presentation layer, however a few
functions took "local" numberings, that is the source number within
the interrupt source controller which is offset from the global
number.  In most cases the function and its caller agreed on this, but
in a few cases it didn't.

This patch cleans this up by always using global numbering.
Translation to the local number is now always and only done when we
look up the individual interrupt source state structure.  This should
remove the existing bugs and with luck reduce the chances of
re-introducing such bugs.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>

qemu_malloc/qemu_free no longer exist after this commit.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

Currently the pseries machine init code builds up an array, envs, of
CPUState pointers for all the cpus in the system.  This is kind of
pointless, given the generic code already has a perfectly good linked list
of the cpus.

In addition, there are a number of places which assume that the cpu's
cpu_index field is equal to its index in this array.  This is true in
practice, because cpu_index values are just assigned sequentially, but
it's conceptually incorrect and may not always be true.

Therefore, this patch abolishes the envs array, and explicitly uses the
generic cpu linked list and cpu_index values throughout.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>

PAPR defines an interrupt control architecture which is logically divided
into ICS (Interrupt Control Presentation, each unit is responsible for
presenting interrupts to a particular "interrupt server", i.e. CPU) and
ICS (Interrupt Control Source, each unit responsible for one or more
hardware interrupts as numbered globally across the system).  All PAPR
virtual IO devices expect to deliver interrupts via this mechanism.  In
Linux, this interrupt controller system is handled by the "xics" driver.

On pSeries systems, access to the interrupt controller is virtualized via
hypercalls and RTAS methods.  However, the virtualized interface is very
similar to the underlying interrupt controller hardware, and similar PICs
exist un-virtualized in some other systems.

This patch implements both the ICP and ICS sides of the PAPR interrupt
controller.  For now, only the hypercall virtualized interface is provided,
however it would be relatively straightforward to graft an emulated
register interface onto the underlying interrupt logic if we want to add
a machine with a hardware ICS/ICP system in the future.

There are some limitations in this implementation: it is assumed for now
that only one instance of the ICS exists, although a full xics system can
have several, each responsible for a different group of hardware irqs.
ICP/ICS can handle both level-sensitve (LSI) and message signalled (MSI)
interrupt inputs.  For now, this implementation supports only MSI
interrupts, since that is used by PAPR virtual IO devices.
Signed-off-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NDavid Gibson <dwg@au1.ibm.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>