Commit Graph

11 Commits

Author SHA1 Message Date
Richard Henderson
a953b5fa15 accel/tcg: Remove cpu_neg()
Now that CPUNegativeOffsetState is part of CPUState,
we can reference it directly.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-10-03 08:01:02 -07:00
Richard Henderson
464dacf609 accel/tcg: Move can_do_io to CPUNegativeOffsetState
Minimize the displacement to can_do_io, since it may
be touched at the start of each TranslationBlock.
It fits into other padding within the substructure.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-10-03 08:01:02 -07:00
Jamie Iles
83ecdb18eb accel/tcg/tcg-accel-ops-rr: ensure fairness with icount
The round-robin scheduler will iterate over the CPU list with an
assigned budget until the next timer expiry and may exit early because
of a TB exit.  This is fine under normal operation but with icount
enabled and SMP it is possible for a CPU to be starved of run time and
the system live-locks.

For example, booting a riscv64 platform with '-icount
shift=0,align=off,sleep=on -smp 2' we observe a livelock once the kernel
has timers enabled and starts performing TLB shootdowns.  In this case
we have CPU 0 in M-mode with interrupts disabled sending an IPI to CPU
1.  As we enter the TCG loop, we assign the icount budget to next timer
interrupt to CPU 0 and begin executing where the guest is sat in a busy
loop exhausting all of the budget before we try to execute CPU 1 which
is the target of the IPI but CPU 1 is left with no budget with which to
execute and the process repeats.

We try here to add some fairness by splitting the budget across all of
the CPUs on the thread fairly before entering each one.  The CPU count
is cached on CPU list generation ID to avoid iterating the list on each
loop iteration.  With this change it is possible to boot an SMP rv64
guest with icount enabled and no hangs.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Jamie Iles <quic_jiles@quicinc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230427020925.51003-3-quic_jiles@quicinc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-05-11 09:53:41 +01:00
Peter Maydell
c7f26ded6d icount: Take iothread lock when running QEMU timers
The function icount_prepare_for_run() is called with the iothread
unlocked, but it can call icount_notify_aio_contexts() which will
run qemu timer handlers. Those are supposed to be run only with
the iothread lock held, so take the lock while we do that.

Since icount mode runs everything on a single thread anyway,
not holding the lock is likely mostly not going to introduce
races, but it can cause us to trip over assertions that we
do hold the lock, such as the one reported in issue 1130.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1130
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Message-id: 20220801164527.3134765-1-peter.maydell@linaro.org
2022-08-09 10:55:14 +01:00
Pavel Dovgalyuk
60618e2d77 replay: rewrite async event handling
This patch decouples checkpoints and async events.
It was a tricky part of replay implementation. Now it becomes
much simpler and easier to maintain.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <165364837856.688121.8785039478408995979.stgit@pasha-ThinkPad-X280>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-06-06 09:26:53 +02:00
Thomas Huth
55d71e0b78 Don't include sysemu/tcg.h if it is not necessary
This header only defines the tcg_allowed variable and the tcg_enabled()
function - which are not required in many files that include this
header. Drop the #include statement there.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20220315144107.1012530-1-thuth@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2022-04-20 12:12:47 -07:00
Marc-André Lureau
0f9668e0c1 Remove qemu-common.h include from most units
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220323155743.1585078-33-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-04-06 14:31:55 +02:00
Philippe Mathieu-Daudé
03ff4f8df9 misc: Add missing "sysemu/cpu-timers.h" include
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220207075426.81934-18-f4bug@amsat.org>
2022-03-06 13:15:42 +01:00
Thomas Huth
ead62c75f6 Do not include hw/boards.h if it's not really necessary
Stop including hw/boards.h in files that don't need it.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20210416171314.2074665-3-thuth@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-05-02 17:24:51 +02:00
Pavel Dovgalyuk
189012fcd7 replay: fix replay of the interrupts
Sometimes interrupt event comes at the same time with
the virtual timers. In this case replay tries to proceed
the timers, because deadline for them is zero.
This patch allows processing interrupts and exceptions
by entering the vCPU execution loop, when deadline is zero,
but checkpoint associated with virtual timers is not ready
to be replayed.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>

Message-Id: <161216312794.2030770.1709657858900983160.stgit@pasha-ThinkPad-X280>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-02-08 14:43:55 +01:00
Claudio Fontana
b86f59c715 accel: replace struct CpusAccel with AccelOpsClass
This will allow us to centralize the registration of
the cpus.c module accelerator operations (in accel/accel-softmmu.c),
and trigger it automatically using object hierarchy lookup from the
new accel_init_interfaces() initialization step, depending just on
which accelerators are available in the code.

Rename all tcg-cpus.c, kvm-cpus.c, etc to tcg-accel-ops.c,
kvm-accel-ops.c, etc, matching the object type names.

Signed-off-by: Claudio Fontana <cfontana@suse.de>
Message-Id: <20210204163931.7358-18-cfontana@suse.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-02-05 10:24:15 -10:00