How is this conditional on CONFIG_TCG? To me it looks like this breaks
!CONFIG_TCG.
Careful, the meson.build in accel/tcg/meson.build is always recursed.
This code was in tcg_ss before, why not simply add it to tcg_ss and then to
specific_ss along with the other tcg pieces?
Ciao,
C
On 3/20/23 11:10, Alex Bennée wrote:
> This doesn't save much as cpu-exec-common still needs to be built
> per-target for its knowledge of CPUState but this helps with keeping
> things organised.
>
> Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
> ---
> accel/tcg/cpu-exec-common.c | 30 ----------------------
> accel/tcg/cpu-exec-softmmu.c | 50 ++++++++++++++++++++++++++++++++++++
> accel/tcg/meson.build | 10 ++++++++
> 3 files changed, 60 insertions(+), 30 deletions(-)
> create mode 100644 accel/tcg/cpu-exec-softmmu.c
>
> diff --git a/accel/tcg/cpu-exec-common.c b/accel/tcg/cpu-exec-common.c
> index e7962c9348..c6b0ad303e 100644
> --- a/accel/tcg/cpu-exec-common.c
> +++ b/accel/tcg/cpu-exec-common.c
> @@ -32,36 +32,6 @@ void cpu_loop_exit_noexc(CPUState *cpu)
> cpu_loop_exit(cpu);
> }
>
> -#if defined(CONFIG_SOFTMMU)
> -void cpu_reloading_memory_map(void)
> -{
> - if (qemu_in_vcpu_thread() && current_cpu->running) {
> - /* The guest can in theory prolong the RCU critical section as long
> - * as it feels like. The major problem with this is that because it
> - * can do multiple reconfigurations of the memory map within the
> - * critical section, we could potentially accumulate an unbounded
> - * collection of memory data structures awaiting reclamation.
> - *
> - * Because the only thing we're currently protecting with RCU is the
> - * memory data structures, it's sufficient to break the critical
> section
> - * in this callback, which we know will get called every time the
> - * memory map is rearranged.
> - *
> - * (If we add anything else in the system that uses RCU to protect
> - * its data structures, we will need to implement some other
> mechanism
> - * to force TCG CPUs to exit the critical section, at which point
> this
> - * part of this callback might become unnecessary.)
> - *
> - * This pair matches cpu_exec's rcu_read_lock()/rcu_read_unlock(),
> which
> - * only protects cpu->as->dispatch. Since we know our caller is about
> - * to reload it, it's safe to split the critical section.
> - */
> - rcu_read_unlock();
> - rcu_read_lock();
> - }
> -}
> -#endif
> -
> void cpu_loop_exit(CPUState *cpu)
> {
> /* Undo the setting in cpu_tb_exec. */
> diff --git a/accel/tcg/cpu-exec-softmmu.c b/accel/tcg/cpu-exec-softmmu.c
> new file mode 100644
> index 0000000000..2318dd8c7d
> --- /dev/null
> +++ b/accel/tcg/cpu-exec-softmmu.c
> @@ -0,0 +1,50 @@
> +/*
> + * Emulator main CPU execution loop, softmmu bits
> + *
> + * Copyright (c) 2003-2005 Fabrice Bellard
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see
> <http://www.gnu.org/licenses/>.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/core/cpu.h"
> +#include "sysemu/cpus.h"
> +
> +void cpu_reloading_memory_map(void)
> +{
> + if (qemu_in_vcpu_thread() && current_cpu->running) {
> + /* The guest can in theory prolong the RCU critical section as long
> + * as it feels like. The major problem with this is that because it
> + * can do multiple reconfigurations of the memory map within the
> + * critical section, we could potentially accumulate an unbounded
> + * collection of memory data structures awaiting reclamation.
> + *
> + * Because the only thing we're currently protecting with RCU is the
> + * memory data structures, it's sufficient to break the critical
> section
> + * in this callback, which we know will get called every time the
> + * memory map is rearranged.
> + *
> + * (If we add anything else in the system that uses RCU to protect
> + * its data structures, we will need to implement some other
> mechanism
> + * to force TCG CPUs to exit the critical section, at which point
> this
> + * part of this callback might become unnecessary.)
> + *
> + * This pair matches cpu_exec's rcu_read_lock()/rcu_read_unlock(),
> which
> + * only protects cpu->as->dispatch. Since we know our caller is about
> + * to reload it, it's safe to split the critical section.
> + */
> + rcu_read_unlock();
> + rcu_read_lock();
> + }
> +}
> diff --git a/accel/tcg/meson.build b/accel/tcg/meson.build
> index aeb20a6ef0..bdc086b90d 100644
> --- a/accel/tcg/meson.build
> +++ b/accel/tcg/meson.build
> @@ -1,3 +1,9 @@
> +#
> +# Currently most things here end up in specific_ss eventually because
> +# they need knowledge of CPUState. Stuff that that doesn't can live in
> +# common user, softmmu or overall code
> +#
> +
> tcg_ss = ss.source_set()
> tcg_ss.add(files(
> 'tcg-all.c',
> @@ -9,6 +15,7 @@ tcg_ss.add(files(
> 'translate-all.c',
> 'translator.c',
> ))
> +
> tcg_ss.add(when: 'CONFIG_USER_ONLY', if_true: files('user-exec.c'))
> tcg_ss.add(when: 'CONFIG_SOFTMMU', if_false: files('user-exec-stub.c'))
> tcg_ss.add(when: 'CONFIG_PLUGIN', if_true: [files('plugin-gen.c')])
> @@ -27,3 +34,6 @@ tcg_module_ss.add(when: ['CONFIG_SOFTMMU', 'CONFIG_TCG'],
> if_true: files(
> 'tcg-accel-ops-icount.c',
> 'tcg-accel-ops-rr.c',
> ))
> +
> +# Common softmmu code
> +softmmu_ss.add(files('cpu-exec-softmmu.c'))
