By exposing FWCfgIoState and FWCfgMemState internals we allow the possibility
for the internal MemoryRegion fields to be mapped by name for boards that wish
to wire up the fw_cfg device themselves.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <1500025208-14827-4-git-send-email-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
These functions are more efficient in the presence of contention.
qemu_co_rwlock_downgrade also guarantees not to block, which may
be useful in some algorithms too.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20170629132749.997-3-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
This defines new QOM object - IOMMUMemoryRegion - with MemoryRegion
as a parent.
This moves IOMMU-related fields from MR to IOMMU MR. However to avoid
dymanic QOM casting in fast path (address_space_translate, etc),
this adds an @is_iommu boolean flag to MR and provides new helper to
do simple cast to IOMMU MR - memory_region_get_iommu. The flag
is set in the instance init callback. This defines
memory_region_is_iommu as memory_region_get_iommu()!=NULL.
This switches MemoryRegion to IOMMUMemoryRegion in most places except
the ones where MemoryRegion may be an alias.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20170711035620.4232-2-aik@ozlabs.ru>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add warn_report(), warn_vreport() for reporting warnings, and
info_report(), info_vreport() for informational messages.
These are implemented them with a helper function factored out of
error_vreport(), suitably generalized. This patch makes no changes
to the output of the original error_report() function.
Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <c89e9980019f296ec9aa38d7689ac4d5c369296d.1499866456.git.alistair.francis@xilinx.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Add bdrv_dirty_bitmap_deserialize_ones() function, which is needed for
qcow2 bitmap loading, to handle unallocated bitmap parts, marked as
all-ones.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20170628120530.31251-7-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Make dirty iter resistant to resetting bits in corresponding HBitmap.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20170628120530.31251-4-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Now that qcow & qcow2 are wired up to get encryption keys
via the QCryptoSecret object, nothing is relying on the
interactive prompting for passwords. All the code related
to password prompting can thus be ripped out.
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170623162419.26068-17-berrange@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Mao Zhongyi <maozy.fnst@cn.fujitsu.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
The user interface specifies job rate limits in bytes/second.
It's pointless to have our internal representation track things
in sectors/second, particularly since we want to move away from
sector-based interfaces.
Fix up a doc typo found while verifying that the ratelimit
code handles the scaling difference.
Repetition of expressions like 'n * BDRV_SECTOR_SIZE' will be
cleaned up later when functions are converted to iterate over
images by bytes rather than by sectors.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Not all platforms check whether a lock is initialized before used. In
particular Linux seems to be more permissive than OSX.
Check initialization state explicitly in our code to catch such bugs
earlier.
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20170704122325.25634-1-famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cleanup: Create and use a typedef for PS2State and stop passing void
pointers. No functional change.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20170606112105.13331-2-kraxel@redhat.com
Add helpers to gather cache info from the host at init-time.
For now, only export the host's I/D cache line sizes, which we
will use to improve cache locality to avoid false sharing.
Suggested-by: Richard Henderson <rth@twiddle.net>
Suggested-by: Geert Martin Ijewski <gm.ijewski@web.de>
Tested-by: Geert Martin Ijewski <gm.ijewski@web.de>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1496794624-4083-1-git-send-email-cota@braap.org>
[rth: Move all implementations from tcg/ppc/]
Signed-off-by: Richard Henderson <rth@twiddle.net>
This module provides fast paths for 64-bit atomic operations on machines
that only have 32-bit atomic access.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20170605123908.18777-11-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
That typedefs are needed on both files. New compilers (F25 where I
work) don't complain about repeating a typedef. But older ones
complain.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Tested and confirmed that the stretch i386 debian qcow2 image on a
raspberry pi 2 works.
Fixes: LP#: 893208 <https://bugs.launchpad.net/qemu/+bug/893208/>
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 20170418191817.10430-1-bobby.prani@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Fix regression from commit 4d43a603c7, where the serial and parallel
headers got removed from char.c, which broke the alias table.
Move the HAVE_CHARDEV_SERIAL/HAVE_CHARDEV_PARPORT to osdep.h instead
of being in separate headers.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
We need to coordinate with the TCG_OVERSIZED_GUEST test in cputlb.c,
and allow 64-bit atomics even though sizeof(void *) == 4.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
So we remove all traces of them.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Not used anymore after moving block migration to use capabilities.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Highlights:
* New "-numa cpu" option
* NUMA distance configuration
* migration/i386 vmstatification
-----BEGIN PGP SIGNATURE-----
iQIcBAABCAAGBQJZFLh3AAoJECgHk2+YTcWmppQQAJe9Y5a3VwHXqvHbwBHX2ysn
RZDAUPd9DWpbM+UUydyKOVIZ7u5RXbbVq4E0NeCD8VYYd+grZB5Wo1cAzy3b4U2j
2s+MDqaPMtZtGoqxTsyQOVoVxazT5Kf1zglK+iUEzik44J7LGdro+ty2Z7Ut2c11
q9rE/GNS78czBm7c4lxgkxXW4N95K/tEGlLtDQ7uct//3U/ZimF+mO6GcbVFlOWT
4iEbOz2sqvBVv22nLJRufiPgFNIW4hizAz5KBWxwGFCCKvT3N6yYNKKjzEpCw+jE
lpjIRODU02yIZZZY841fLRtyrk7p4zORS8jRaHTdEJgb5bGc/YazxxVL8nzRQT1W
VxFwAMd+UNrDkV24hpN++Ln2O+b3kwcGZ7uA/qu9d5WvSYUKXlHqcMJ35q6zuhAI
/ecfYO7EZfVP86VjIt5IH04iV8RChA9Q6de+kQEFa6wHUxufeCOwCFqukGo8zj07
plX8NcjnzYmSXKnYjHOHao4rKT+DiJhRB60rFiMeKP/qvKbZPjtgsIeonhHm53qZ
/QwkhowahHKkpAnetIl0QHm8KS4YudAofMi/Fl+he4gRkEbSQVAo6iQb2L4cjcLC
LNSDDsIVWGem4gCR+vcsFqB3lggRDfltHXm15JKh92UMpOr6RI6s8pD55T7EdnPC
CfdxWB5kYM6/lLbOHj94
=48wH
-----END PGP SIGNATURE-----
Merge remote-tracking branch 'ehabkost/tags/x86-and-machine-pull-request' into staging
x86 and machine queue, 2017-05-11
Highlights:
* New "-numa cpu" option
* NUMA distance configuration
* migration/i386 vmstatification
# gpg: Signature made Thu 11 May 2017 08:16:07 PM BST
# gpg: using RSA key 0x2807936F984DC5A6
# gpg: Good signature from "Eduardo Habkost <ehabkost@redhat.com>"
# gpg: Note: This key has expired!
# Primary key fingerprint: 5A32 2FD5 ABC4 D3DB ACCF D1AA 2807 936F 984D C5A6
* ehabkost/tags/x86-and-machine-pull-request: (29 commits)
migration/i386: Remove support for pre-0.12 formats
vmstatification: i386 FPReg
migration/i386: Remove old non-softfloat 64bit FP support
tests: check -numa node,cpu=props_list usecase
numa: add '-numa cpu,...' option for property based node mapping
numa: remove node_cpu bitmaps as they are no longer used
numa: use possible_cpus for not mapped CPUs check
machine: call machine init from wrapper
numa: remove no longer need numa_post_machine_init()
tests: numa: add case for QMP command query-cpus
QMP: include CpuInstanceProperties into query_cpus output output
virt-arm: get numa node mapping from possible_cpus instead of numa_get_node_for_cpu()
spapr: get numa node mapping from possible_cpus instead of numa_get_node_for_cpu()
pc: get numa node mapping from possible_cpus instead of numa_get_node_for_cpu()
numa: do default mapping based on possible_cpus instead of node_cpu bitmaps
numa: mirror cpu to node mapping in MachineState::possible_cpus
numa: add check that board supports cpu_index to node mapping
virt-arm: add node-id property to CPU
pc: add node-id property to CPU
spapr: add node-id property to sPAPR core
...
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
ctpopl() has a better implementation than hweight_long() and ui/vnc.c
being the last user of hweight_long(), we can simply remove it.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1489415605-13105-1-git-send-email-clg@kaod.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
When there are more nodes than available memory to put the minimum
allowed memory by node, all the memory is put on the last node.
This is because we put (ram_size / nb_numa_nodes) &
~((1 << mc->numa_mem_align_shift) - 1); on each node, and in this
case the value is 0. This is particularly true with pseries,
as the memory must be aligned to 256MB.
To avoid this problem, this patch uses an error diffusion algorithm [1]
to distribute equally the memory on nodes.
We introduce numa_auto_assign_ram() function in MachineClass
to keep compatibility between machine type versions.
The legacy function is used with pseries-2.9, pc-q35-2.9 and
pc-i440fx-2.9 (and previous), the new one with all others.
Example:
qemu-system-ppc64 -S -nographic -nodefaults -monitor stdio -m 1G -smp 8 \
-numa node -numa node -numa node \
-numa node -numa node -numa node
Before:
(qemu) info numa
6 nodes
node 0 cpus: 0 6
node 0 size: 0 MB
node 1 cpus: 1 7
node 1 size: 0 MB
node 2 cpus: 2
node 2 size: 0 MB
node 3 cpus: 3
node 3 size: 0 MB
node 4 cpus: 4
node 4 size: 0 MB
node 5 cpus: 5
node 5 size: 1024 MB
After:
(qemu) info numa
6 nodes
node 0 cpus: 0 6
node 0 size: 0 MB
node 1 cpus: 1 7
node 1 size: 256 MB
node 2 cpus: 2
node 2 size: 0 MB
node 3 cpus: 3
node 3 size: 256 MB
node 4 cpus: 4
node 4 size: 256 MB
node 5 cpus: 5
node 5 size: 256 MB
[1] https://en.wikipedia.org/wiki/Error_diffusion
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20170502162955.1610-2-lvivier@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
[ehabkost: s/ram_size/size/ at numa_default_auto_assign_ram()]
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
They are wrappers of POSIX fcntl "file private locking", with a
convenient "try lock" wrapper implemented with F_OFD_GETLK.
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
SocketAddressLegacy is a simple union, and simple unions are awkward:
they have their variant members wrapped in a "data" object on the
wire, and require additional indirections in C. SocketAddress is the
equivalent flat union. Convert all users of SocketAddressLegacy to
SocketAddress, except for existing external interfaces.
See also commit fce5d53..9445673 and 85a82e8..c5f1ae3.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1493192202-3184-7-git-send-email-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[Minor editing accident fixed, commit message and a comment tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
The next commit will rename SocketAddressFlat to SocketAddress, and
the commit after that will replace most uses of SocketAddressLegacy by
SocketAddress, replacing most of this commit's renames right back.
Note that checkpatch emits a few "line over 80 characters" warnings.
The long lines are all temporary; the SocketAddressLegacy replacement
will shorten them again.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1493192202-3184-5-git-send-email-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
I'm going to flatten SocketAddress: rename SocketAddress to
SocketAddressLegacy, SocketAddressFlat to SocketAddress, eliminate
SocketAddressLegacy except in external interfaces.
inet_parse() returns a newly allocated InetSocketAddress. Lift the
allocation from inet_parse() into its caller socket_parse() to prepare
for flattening SocketAddress.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1493192202-3184-3-git-send-email-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[Straightforward rebase]
QEMU_BUILD_BUG_ON should use C11's _Static_assert, if the compiler supports it,
to provide more readable messages on failure.
We check for _Static_assert in configure, and set CONFIG_STATIC_ASSERT
accordingly. QEMU_BUILD_BUG_ON invokes _Static_assert if CONFIG_STATIC_ASSERT
is defined, and reverts to the old way otherwise.
That way, systems without C11 conforming compiler will still have the old
messages, as verified by intentionally breaking the configure check.
the following example output was generated by inverting the condition in
QEMU_BUILD_BUG_ON:
without _Static_assert:
> In file included from /qemu/include/qemu/osdep.h:36:0,
> from /qemu/qga/commands.c:13:
> /qemu/qga/commands.c: In function ‘qmp_guest_exec_status’:
> /qemu/include/qemu/compiler.h:89:12: error: negative width in bit-field ‘<anonymous>’
> struct { \
> ^
> /qemu/include/qemu/compiler.h:96:38: note: in expansion of macro QEMU_BUILD_BUG_ON_STRUCT’
> #define QEMU_BUILD_BUG_ON(x) typedef QEMU_BUILD_BUG_ON_STRUCT(x) \
> ^~~~~~~~~~~~~~~~~~~~~~~~
> /qemu/include/qemu/atomic.h:146:5: note: in expansion of macro ‘QEMU_BUILD_BUG_ON’
> QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \
> ^~~~~~~~~~~~~~~~~
> /qemu/include/qemu/atomic.h:417:5: note: in expansion of macro ‘atomic_load_acquire’
> atomic_load_acquire(ptr)
> ^~~~~~~~~~~~~~~~~~~
> /qemu/qga/commands.c:160:21: note: in expansion of macro ‘atomic_mb_read’
> bool finished = atomic_mb_read(&gei->finished);
> ^~~~~~~~~~~~~~
with _Static_assert:
> In file included from /qemu/include/qemu/osdep.h:36:0,
> from /qemu/qga/commands.c:13:
> /qemu/qga/commands.c: In function ‘qmp_guest_exec_status’:
> /qemu/include/qemu/compiler.h:94:30: error: static assertion failed: "not expecting: sizeof(*&gei->finished) > sizeof(void *)"
> #define QEMU_BUILD_BUG_ON(x) _Static_assert((x), #x)
> ^
> /qemu/include/qemu/atomic.h:146:5: note: in expansion of macro ‘QEMU_BUILD_BUG_ON’
> QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \
> ^~~~~~~~~~~~~~~~~
> /qemu/include/qemu/atomic.h:417:5: note: in expansion of macro ‘atomic_load_acquire’
> atomic_load_acquire(ptr)
> ^~~~~~~~~~~~~~~~~~~
> /qemu/qga/commands.c:160:21: note: in expansion of macro ‘atomic_mb_read’
> bool finished = atomic_mb_read(&gei->finished);
> ^~~~~~~~~~~~~~
Signed-off-by: Andreas Grapentin <andreas@grapentin.org>
Message-Id: <20170314165953.18506-1-andreas@grapentin.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch adds support for getting and using a local copy of the dirty
bitmap.
memory_region_snapshot_and_clear_dirty() will create a snapshot of the
dirty bitmap for the specified range, clear the dirty bitmap and return
the copy. The returned bitmap can be a bit larger than requested, the
range is expanded so the code can copy unsigned longs from the bitmap
and avoid atomic bit update operations.
memory_region_snapshot_get_dirty() will return the dirty status of
pages, pretty much like memory_region_get_dirty(), but using the copy
returned by memory_region_copy_and_clear_dirty().
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20170421091632.30900-3-kraxel@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
We already require gcc 4.1 or newer (for the atomic
support), so the fallback codepaths for older gcc
versions than that are now dead code and we can
just delete them.
NB: clang reports itself as gcc 4.2 (regardless of
clang version), so clang won't be using the fallbacks
either.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
It's a variant of qemu_coroutine_enter with an explicit AioContext
parameter.
Signed-off-by: Fam Zheng <famz@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
By holding off updates to timer_state.qemu_icount we can run into
trouble when the non-vCPU thread needs to know the time. This helper
ensures we atomically update timers_state.qemu_icount based on what
has been currently executed.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
SocketAddress is a simple union, and simple unions are awkward: they
have their variant members wrapped in a "data" object on the wire, and
require additional indirections in C. I intend to limit its use to
existing external interfaces. New ones should use SocketAddressFlat.
I further intend to convert all internal interfaces to
SocketAddressFlat. This helper should go away then.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1490895797-29094-8-git-send-email-armbru@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
The multithreaded TCG implementation exposed deadlocks in the win32
condition variables: as implemented, qemu_cond_broadcast waited on
receivers, whereas the pthreads API it was intended to emulate does
not. This was causing a deadlock because broadcast was called while
holding the IO lock, as well as all possible waiters blocked on the
same lock.
This patch replaces all the custom synchronisation code for mutexes
and condition variables with native Windows primitives (SRWlocks and
condition variables) with the same semantics as their POSIX
equivalents. To enable that, it requires a Windows Vista or newer host
OS.
Signed-off-by: Andrey Shedel <ashedel@microsoft.com>
[AB: edited commit message]
Signed-off-by: Andrew Baumann <Andrew.Baumann@microsoft.com>
Message-Id: <20170324220141.10104-1-Andrew.Baumann@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
qemu-ga's socket activation support was not obeying the LISTEN_PID
environment variable, which avoids that a process uses a socket-activation
file descriptor meant for its parent.
Mess can for example ensue if a process forks a children before consuming
the socket-activation file descriptor and therefore setting O_CLOEXEC
on it.
Luckily, qemu-nbd also got socket activation code, and its copy does
support LISTEN_PID. Some extra fixups are needed to ensure that the
code can be used for both, but that's what this patch does. The
main change is to replace get_listen_fds's "consume" argument with
the FIRST_SOCKET_ACTIVATION_FD macro from the qemu-nbd code.
Cc: "Richard W.M. Jones" <rjones@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
icount has become much slower after tcg_cpu_exec has stopped
using the BQL. There is also a latent bug that is masked by
the slowness.
The slowness happens because every occurrence of a QEMU_CLOCK_VIRTUAL
timer now has to wake up the I/O thread and wait for it. The rendez-vous
is mediated by the BQL QemuMutex:
- handle_icount_deadline wakes up the I/O thread with BQL taken
- the I/O thread wakes up and waits on the BQL
- the VCPU thread releases the BQL a little later
- the I/O thread raises an interrupt, which calls qemu_cpu_kick
- the VCPU thread notices the interrupt, takes the BQL to
process it and waits on it
All this back and forth is extremely expensive, causing a 6 to 8-fold
slowdown when icount is turned on.
One may think that the issue is that the VCPU thread is too dependent
on the BQL, but then the latent bug comes in. I first tried removing
the BQL completely from the x86 cpu_exec, only to see everything break.
The only way to fix it (and make everything slow again) was to add a dummy
BQL lock/unlock pair.
This is because in -icount mode you really have to process the events
before the CPU restarts executing the next instruction. Therefore, this
series moves the processing of QEMU_CLOCK_VIRTUAL timers straight in
the vCPU thread when running in icount mode.
The required changes include:
- make the timer notification callback wake up TCG's single vCPU thread
when run from another thread. By using async_run_on_cpu, the callback
can override all_cpu_threads_idle() when the CPU is halted.
- move handle_icount_deadline after qemu_tcg_wait_io_event, so that
the timer notification callback is invoked after the dummy work item
wakes up the vCPU thread
- make handle_icount_deadline run the timers instead of just waking the
I/O thread.
- stop processing the timers in the main loop
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There is no change for now, because the callback just invokes
qemu_notify_event.
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>