Commit Graph

22 Commits

Author SHA1 Message Date
Chetan Pant d6ea423635 overall/alpha tcg cpus|hppa: Fix Lesser GPL version number
There is no "version 2" of the "Lesser" General Public License.
It is either "GPL version 2.0" or "Lesser GPL version 2.1".
This patch replaces all occurrences of "Lesser GPL version 2" with
"Lesser GPL version 2.1" in comment section.

Signed-off-by: Chetan Pant <chetan4windows@gmail.com>
Message-Id: <20201023123353.19796-1-chetan4windows@gmail.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2020-11-15 16:43:54 +01:00
Stefan Hajnoczi d73415a315 qemu/atomic.h: rename atomic_ to qatomic_
clang's C11 atomic_fetch_*() functions only take a C11 atomic type
pointer argument. QEMU uses direct types (int, etc) and this causes a
compiler error when a QEMU code calls these functions in a source file
that also included <stdatomic.h> via a system header file:

  $ CC=clang CXX=clang++ ./configure ... && make
  ../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid)

Avoid using atomic_*() names in QEMU's atomic.h since that namespace is
used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h
and <stdatomic.h> can co-exist. I checked /usr/include on my machine and
searched GitHub for existing "qatomic_" users but there seem to be none.

This patch was generated using:

  $ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \
    sort -u >/tmp/changed_identifiers
  $ for identifier in $(</tmp/changed_identifiers); do
        sed -i "s%\<$identifier\>%q$identifier%g" \
            $(git grep -I -l "\<$identifier\>")
    done

I manually fixed line-wrap issues and misaligned rST tables.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200923105646.47864-1-stefanha@redhat.com>
2020-09-23 16:07:44 +01:00
Philippe Mathieu-Daudé 421a75e283 cpus: Move CPU code from exec.c to cpus-common.c
This code was introduced with SMP support in commit 6a00d60127,
later commit 267f685b8b moved CPU list management to common code
but forgot this code. Move now and simplify ifdef'ry.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200702104017.14057-1-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-07-10 18:02:24 -04:00
Emilio G. Cota 0c0fcc2052 cpu: convert queued work to a QSIMPLEQ
We convert queued work to a QSIMPLEQ, instead of
open-coding it.

While at it, make sure that all accesses to the list are
performed while holding the list's lock.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Robert Foley <robert.foley@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200609200738.445-3-robert.foley@linaro.org>
Message-Id: <20200612190237.30436-6-alex.bennee@linaro.org>
2020-06-16 14:49:05 +01:00
Alex Bennée 716386e397 cpus-common: ensure auto-assigned cpu_indexes don't clash
Basing the cpu_index on the number of currently allocated vCPUs fails
when vCPUs aren't removed in a LIFO manner. This is especially true
when we are allocating a cpu_index for each guest thread in
linux-user where there is no ordering constraint on their allocation
and de-allocation.

[I've dropped the assert which is there to guard against out-of-order
removal as this should probably be caught higher up the stack. Maybe
we could just ifdef CONFIG_SOFTTMU it?]

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Igor Mammedow <imammedo@redhat.com>
Cc: Nikolay Igotti <igotti@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20200520140541.30256-13-alex.bennee@linaro.org>
2020-05-27 14:26:49 +01:00
Daniel Brodsky 6e8a355de6 lockable: replaced locks with lock guard macros where appropriate
- ran regexp "qemu_mutex_lock\(.*\).*\n.*if" to find targets
- replaced result with QEMU_LOCK_GUARD if all unlocks at function end
- replaced result with WITH_QEMU_LOCK_GUARD if unlock not at end

Signed-off-by: Daniel Brodsky <dnbrdsky@gmail.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-id: 20200404042108.389635-3-dnbrdsky@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2020-05-04 16:07:43 +01:00
Emilio G. Cota cfbc3c6083 cpu: introduce cpu_in_exclusive_context()
Suggested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
[AJB: moved inside start/end_exclusive fns + cleanup]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2019-10-28 15:12:38 +00:00
Peter Maydell f3b8f18ebf Monitor patches for 2019-08-21
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Merge remote-tracking branch 'remotes/armbru/tags/pull-monitor-2019-08-21' into staging

Monitor patches for 2019-08-21

# gpg: Signature made Wed 21 Aug 2019 16:35:07 BST
# gpg:                using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653
# gpg:                issuer "armbru@redhat.com"
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full]
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>" [full]
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-monitor-2019-08-21:
  monitor/qmp: Update comment for commit 4eaca8de26
  qdev: Collect HMP handlers command handlers in qdev-monitor.c
  qapi: Move query-target from misc.json to machine.json
  hw/core: Move cpu.c, cpu.h from qom/ to hw/core/

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-08-22 10:31:21 +01:00
Markus Armbruster 2e5b09fd0e hw/core: Move cpu.c, cpu.h from qom/ to hw/core/
Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190709152053.16670-2-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
[Rebased onto merge commit 95a9457fd44; missed instances of qom/cpu.h
in comments replaced]
2019-08-21 13:24:01 +02:00
Roman Kagan e533f45d7d cpus-common: nuke finish_safe_work
It was introduced in commit ab129972c8,
with the following motivation:

  Because start_exclusive uses CPU_FOREACH, merge exclusive_lock with
  qemu_cpu_list_lock: together with a call to exclusive_idle (via
  cpu_exec_start/end) in cpu_list_add, this protects exclusive work
  against concurrent CPU addition and removal.

However, it seems to be redundant, because the cpu-exclusive
infrastructure provides suffificent protection against the newly added
CPU starting execution while the cpu-exclusive work is running, and the
aforementioned traversing of the cpu list is protected by
qemu_cpu_list_lock.

Besides, this appears to be the only place where the cpu-exclusive
section is entered with the BQL taken, which has been found to trigger
AB-BA deadlock as follows:

    vCPU thread                             main thread
    -----------                             -----------
async_safe_run_on_cpu(self,
                      async_synic_update)
...                                         [cpu hot-add]
process_queued_cpu_work()
  qemu_mutex_unlock_iothread()
                                            [grab BQL]
  start_exclusive()                         cpu_list_add()
  async_synic_update()                        finish_safe_work()
    qemu_mutex_lock_iothread()                  cpu_exec_start()

So remove it.  This paves the way to establishing a strict nesting rule
of never entering the exclusive section with the BQL taken.

Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Message-Id: <20190523105440.27045-2-rkagan@virtuozzo.com>
2019-08-20 17:26:22 +02:00
Paolo Bonzini eae3eb3e18 qemu/queue.h: simplify reverse access to QTAILQ
The new definition of QTAILQ does not require passing the headname,
remove it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-01-11 15:46:55 +01:00
Emilio G. Cota 068a5ea02f qom: convert the CPU list to RCU
Iterating over the list without using atomics is undefined behaviour,
since the list can be modified concurrently by other threads (e.g.
every time a new thread is created in user-mode).

Fix it by implementing the CPU list as an RCU QTAILQ. This requires
a little bit of extra work to traverse list in reverse order (see
previous patch), but other than that the conversion is trivial.

Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <20180819091335.22863-12-cota@braap.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-08-23 18:46:25 +02:00
Paolo Bonzini 14e6fe12a7 *_run_on_cpu: introduce run_on_cpu_data type
This changes the *_run_on_cpu APIs (and helpers) to pass data in a
run_on_cpu_data type instead of a plain void *. This is because we
sometimes want to pass a target address (target_ulong) and this fails on
32 bit hosts emulating 64 bit guests.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20161027151030.20863-24-alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-10-31 15:00:25 +01:00
Paolo Bonzini c265e976f4 cpus-common: lock-free fast path for cpu_exec_start/end
Set cpu->running without taking the cpu_list lock, only requiring it if
there is a concurrent exclusive section.  This requires adding a new
field to CPUState, which records whether a running CPU is being counted
in pending_cpus.

When an exclusive section is started concurrently with cpu_exec_start,
cpu_exec_start can use the new field to determine if it has to wait for
the end of the exclusive section.  Likewise, cpu_exec_end can use it to
see if start_exclusive is waiting for that CPU.

This a separate patch for easier bisection of issues.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:30 +02:00
Paolo Bonzini 53f5ed9506 cpus-common: Introduce async_safe_run_on_cpu()
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:30 +02:00
Paolo Bonzini 758e1b2b62 cpus-common: simplify locking for start_exclusive/end_exclusive
It is not necessary to hold qemu_cpu_list_mutex throughout the
exclusive section, because no other exclusive section can run
while pending_cpus != 0.

exclusive_idle() is called in cpu_exec_start(), and that prevents
any CPUs created after start_exclusive() from entering cpu_exec()
during an exclusive section.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:30 +02:00
Paolo Bonzini cf07da65f3 cpus-common: remove redundant call to exclusive_idle()
No need to call exclusive_idle() from cpu_exec_end since it is done
immediately afterwards in cpu_exec_start.  Any exclusive section could
run as soon as cpu_exec_end leaves, because cpu->running is false and the
mutex is not taken, so the call does not add any protection either.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:30 +02:00
Paolo Bonzini c978b31687 cpus-common: always defer async_run_on_cpu work items
async_run_on_cpu is only called from the I/O thread, not from CPU threads,
so it doesn't make any difference.  It will make a difference however
for async_safe_run_on_cpu.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:30 +02:00
Paolo Bonzini ab129972c8 cpus-common: move exclusive work infrastructure from linux-user
This will serve as the base for async_safe_run_on_cpu.  Because
start_exclusive uses CPU_FOREACH, merge exclusive_lock with
qemu_cpu_list_lock: together with a call to exclusive_idle (via
cpu_exec_start/end) in cpu_list_add, this protects exclusive work
against concurrent CPU addition and removal.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:30 +02:00
Paolo Bonzini 0e55539c07 cpus-common: fix uninitialized variable use in run_on_cpu
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:30 +02:00
Sergey Fedorov d148d90ee8 cpus-common: move CPU work item management to common code
Make CPU work core functions common between system and user-mode
emulation. User-mode does not use run_on_cpu, so do not implement it.

Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com>
Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <1470158864-17651-10-git-send-email-alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:30 +02:00
Paolo Bonzini 267f685b8b cpus-common: move CPU list management to common code
Add a mutex for the CPU list to system emulation, as it will be used to
manage safe work.  Abstract manipulation of the CPU list in new functions
cpu_list_add and cpu_list_remove.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-09-27 11:57:29 +02:00