The begin and end callbacks can be used to prepare for the polling loop
and clean up when polling stops.  Note that they may only be called once
for multiple aio_poll() calls if polling continues to succeed.  Once
polling fails the end callback is invoked before aio_poll() resumes file
descriptor monitoring.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-11-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Polling should disable virtqueue notifications but that requires nested
virtio_queue_set_notification() calls.  Turn vq->notification into a
counter so it is possible to do nesting.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-10-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

The guest does not need to kick the virtqueue while we are processing
it.  This reduces the number of vmexits during periods of heavy I/O.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-9-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

The guest does not need to kick the virtqueue while we are processing
it.  This reduces the number of vmexits during periods of heavy I/O.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-8-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Poll mode can be configured with -object iothread,poll-max-ns=NUM.
Polling is disabled with a value of 0 nanoseconds.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-7-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

The Linux AIO userspace ABI includes a ring that is shared with the
kernel.  This allows userspace programs to process completions without
system calls.

Add an AioContext poll handler to check for completions in the ring.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-6-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Add an AioContext poll handler to detect new virtqueue buffers without
waiting for a guest->host notification.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-5-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

The AioContext event loop uses ppoll(2) or epoll_wait(2) to monitor file
descriptors or until a timer expires.  In cases like virtqueues, Linux
AIO, and ThreadPool it is technically possible to wait for events via
polling (i.e. continuously checking for events without blocking).

Polling can be faster than blocking syscalls because file descriptors,
the process scheduler, and system calls are bypassed.

The main disadvantage to polling is that it increases CPU utilization.
In classic polling configuration a full host CPU thread might run at
100% to respond to events as quickly as possible.  This patch implements
a timeout so we fall back to blocking syscalls if polling detects no
activity.  After the timeout no CPU cycles are wasted on polling until
the next event loop iteration.

The run_poll_handlers_begin() and run_poll_handlers_end() trace events
are added to aid performance analysis and troubleshooting.  If you need
to know whether polling mode is being used, trace these events to find
out.

Note that the AioContext is now re-acquired before disabling notify_me
in the non-polling case.  This makes the code cleaner since notify_me
was enabled outside the non-polling AioContext release region.  This
change is correct since it's safe to keep notify_me enabled longer
(disabling is an optimization) but potentially causes unnecessary
event_notifer_set() calls.  I think the chance of performance regression
is small here.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-4-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

The new AioPollFn io_poll() argument to aio_set_fd_handler() and
aio_set_event_handler() is used in the next patch.

Keep this code change separate due to the number of files it touches.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-3-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Polling mode will not call ppoll(2)/epoll_wait(2).  Therefore we know
there are no fds ready and should avoid looping over fd handlers in
aio_dispatch().

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20161201192652.9509-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

It was not obvious to me why "qemu/osdep.h" must be the first #include.
This documents the rationale and the overall #include order.

Cc: Fam Zheng <famz@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1479307161-24658-1-git-send-email-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

# gpg: Signature made Tue 27 Dec 2016 17:52:12 GMT
# gpg:                using RSA key 0xF30C38BD3F2FBE3C
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>"
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>"
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>"
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier/tags/m68k-for-2.9-pull-request:
  target-m68k: free TCG variables that are not
  target-m68k: add rol/ror/roxl/roxr instructions
  target-m68k: Inline shifts
  target-m68k: Do not cpu_abort on undefined insns
  target-m68k: Implement 680x0 movem
  target-m68k: add cas/cas2 ops
  target-m68k: add abcd/sbcd/nbcd
  target-m68k: add 680x0 divu/divs variants
  target-m68k: add 64bit mull
  target-m68k: add cmpm
  target-m68k: Split gen_lea and gen_ea
  target-m68k: Delay autoinc writeback

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

This is a cleanup patch. It adds call to tcg_temp_free()
when it is missing.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twiddle.net>

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twiddle.net>

Also manage word and byte operands and fix the computation of
overflow in the case of M68000 arithmetic shifts.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-Id: <1478699171-10637-4-git-send-email-rth@twiddle.net>

Report this properly via exception and, importantly, allow
the disassembler the chance to tell us what insn is not handled.

Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-Id: <1478699171-10637-3-git-send-email-rth@twiddle.net>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

680x0 movem can load/store words and long words and can use more
addressing modes.  Coldfire can only use long words with (Ax) and
(d16,Ax) addressing modes.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-Id: <1478699171-10637-2-git-send-email-rth@twiddle.net>

Implement CAS using cmpxchg.
Implement CAS2 using helper and either cmpxchg when
the 32bit addresses are consecutive, or with
parallel_cpus+cpu_loop_exit_atomic() otherwise.

Suggested-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twiddle.net>

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twiddle.net>

Update helper to set the throwing location in case of div-by-0.
Cleanup divX.w and add quad word variants of divX.l.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twidle.net>
[laurent: modified to clear Z on overflow, as found with risu]

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twidle.net>

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-Id: <1477604609-2206-2-git-send-email-laurent@vivier.eu>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-Id: <1478206203-4606-4-git-send-email-rth@twiddle.net>

Provide gen_lea_mode and gen_ea_mode, where the mode can be
specified manually, rather than taken from the instruction.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-Id: <1478206203-4606-3-git-send-email-rth@twiddle.net>

Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-Id: <1478206203-4606-2-git-send-email-rth@twiddle.net>

target-arm queue:
 * add VBAR support to ARM1176 CPUs
 * hw/i2c: add NULL check to i2c slave init callbacks
 * pxa2xx.c: fix trailing whitespace
 * aspeed: various cleanups
 * aspeed: add romulus-bmc board
 * virt: add 2.9 machine type
 * gicv3: don't signal Pending+Active interrupts to CPU
 * gicv3: fix incorrect usage of fieldoffset
 * arm: log AArch64 exception returns
 * gicv3: fix aff3 field in typer register
 * aarch64: fix ldst_single_struct on BE hosts
 * aarch64: fix vec_reg_offset on BE hosts
 * arm: fix Cortex-A8 MVFR1 register value
 * cadence_uart: check if receiver timeout counter disabled
 * cadence_uart: check register values on migration

# gpg: Signature made Tue 27 Dec 2016 15:19:26 GMT
# gpg:                using RSA key 0x3C2525ED14360CDE
# gpg: Good signature from "Peter Maydell <peter.maydell@linaro.org>"
# gpg:                 aka "Peter Maydell <pmaydell@gmail.com>"
# gpg:                 aka "Peter Maydell <pmaydell@chiark.greenend.org.uk>"
# Primary key fingerprint: E1A5 C593 CD41 9DE2 8E83  15CF 3C25 25ED 1436 0CDE

* remotes/pmaydell/tags/pull-target-arm-20161227: (25 commits)
  target-arm: Add VBAR support to ARM1176 CPUs
  hw/i2c: Add a NULL check for i2c slave init callbacks
  hw/arm: remove trailing whitespace
  aspeed/smc: set the number of flash modules for the FMC controller
  aspeed/smc: improve segment register support
  aspeed/scu: fix SCU region size
  aspeed: change SoC revision of the palmetto-bmc machine
  aspeed: add the definitions for the AST2400 A1 SoC
  aspeed: add a memory region for SRAM
  aspeed: add support for the romulus-bmc board
  aspeed: extend the board configuration with flash models
  aspeed: attach the second SPI controller object to the SoC
  aspeed: remove cannot_destroy_with_object_finalize_yet
  aspeed: QOMify the CPU object and attach it to the SoC
  m25p80: add support for the mx66l1g45g
  hw/arm/virt: add 2.9 machine type
  hw/intc/arm_gicv3: Don't signal Pending+Active interrupts to CPU
  hw/intc/arm_gicv3: Remove incorrect usage of fieldoffset
  target-arm: Log AArch64 exception returns
  hw/intc/arm_gicv3_common: fix aff3 in typer
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

ARM1176 CPUs have TrustZone support and can use the Vector Base
Address Register, but currently, qemu only adds VBAR support to ARMv7
CPUs. Fix this by adding a new feature ARM_FEATURE_VBAR which can used
for ARMv7 and ARM1176 CPUs.

The VBAR feature is always set for ARMv7 because some legacy boards
require it even if this is not architecturally correct.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 1481810970-9692-1-git-send-email-clg@kaod.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Add a NULL check for i2c slave init callbacks, so that we no longer
need to implement empty init functions.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Message-id: 20161202054617.6749-4-alastair@au1.ibm.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: squashed in later tweak from Alistair to if() phrasing]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Remove trailing whitespace in hw/arm/pxa2xx.c

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Message-id: 20161202054617.6749-3-alastair@au1.ibm.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Add a new configuration field at the board level and propagate the
value using the "num-cs" property of the FMC controller model.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 1480434248-27138-14-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

The HW does not enforce all the rules in the specs and allows a few
"curious" setups like zero size segments and overlaps. So change the
model to be in sync but keep the warnings which are always interesting
for debug.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Message-id: 1480434248-27138-13-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Message-id: 1480434248-27138-12-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

The palmetto BMC machine uses a AST2400 revision A1 SoC.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Message-id: 1480434248-27138-11-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

There is not much differences with the A0 revision apart from the DDR
calibration.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Message-id: 1480434248-27138-10-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

The size of the SRAM depends on the SoC model, so use a per-soc
definition when creating the region.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Message-id: 1480434248-27138-9-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

The Romulus machine is an OpenPOWER system with an AST2500 SoC for
the BMC and a POWER9 chip for the host. It does not make much
difference for qemu a part from the fact that the FMC controller has
two SPI flash module.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Message-id: 1480434248-27138-8-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Future machine will use different flash models for the FMC and the SPI
controllers.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Message-id: 1480434248-27138-7-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Message-id: 1480434248-27138-6-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

With commit ce5b1bbf ("exec: move cpu_exec_init() calls to realize
functions"), we can now remove cannot_destroy_with_object_finalize_yet.

Suggested-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 1480434248-27138-5-git-send-email-clg@kaod.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Message-id: 1480434248-27138-4-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Marcin Krzeminski <marcin.krzeminski@nokia.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Message-id: 1480434248-27138-3-git-send-email-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>