Paolo Bonzini <pbonz...@redhat.com> writes:
> 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.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> ---
> Makefile.target | 2 +-
> bsd-user/main.c | 9 +----
> cpus-common.c | 83
> +++++++++++++++++++++++++++++++++++++++++++++++
> exec.c | 37 ++-------------------
> include/exec/cpu-all.h | 4 +++
> include/exec/cpu-common.h | 2 ++
> include/exec/exec-all.h | 11 -------
> include/qom/cpu.h | 12 +++++++
> linux-user/main.c | 17 +++-------
> vl.c | 1 +
> 10 files changed, 110 insertions(+), 68 deletions(-)
> create mode 100644 cpus-common.c
>
> diff --git a/Makefile.target b/Makefile.target
> index 8c7a072..5f2cf85 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -86,7 +86,7 @@ all: $(PROGS) stap
> # cpu emulator library
> obj-y = exec.o translate-all.o cpu-exec.o
> obj-y += translate-common.o
> -obj-y += cpu-exec-common.o
> +obj-y += cpu-exec-common.o cpus-common.o
> obj-y += tcg/tcg.o tcg/tcg-op.o tcg/optimize.o
> obj-$(CONFIG_TCG_INTERPRETER) += tci.o
> obj-y += tcg/tcg-common.o
> diff --git a/bsd-user/main.c b/bsd-user/main.c
> index 0fb08e4..591c424 100644
> --- a/bsd-user/main.c
> +++ b/bsd-user/main.c
> @@ -95,14 +95,6 @@ void fork_end(int child)
> }
> }
>
> -void cpu_list_lock(void)
> -{
> -}
> -
> -void cpu_list_unlock(void)
> -{
> -}
> -
> #ifdef TARGET_I386
> /***********************************************************/
> /* CPUX86 core interface */
> @@ -748,6 +740,7 @@ int main(int argc, char **argv)
> if (argc <= 1)
> usage();
>
> + qemu_init_cpu_list();
> module_call_init(MODULE_INIT_QOM);
>
> if ((envlist = envlist_create()) == NULL) {
> diff --git a/cpus-common.c b/cpus-common.c
> new file mode 100644
> index 0000000..52198d8
> --- /dev/null
> +++ b/cpus-common.c
> @@ -0,0 +1,83 @@
> +/*
> + * CPU thread main loop - common bits for user and system mode emulation
> + *
> + * 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 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 "cpu.h"
> +#include "sysemu/cpus.h"
> +#include "exec/memory-internal.h"
> +
> +static QemuMutex qemu_cpu_list_mutex;
> +
> +void qemu_init_cpu_list(void)
> +{
> + qemu_mutex_init(&qemu_cpu_list_mutex);
> +}
> +
> +void cpu_list_lock(void)
> +{
> + qemu_mutex_lock(&qemu_cpu_list_mutex);
> +}
> +
> +void cpu_list_unlock(void)
> +{
> + qemu_mutex_unlock(&qemu_cpu_list_mutex);
> +}
> +
> +static bool cpu_index_auto_assigned;
> +
> +static int cpu_get_free_index(void)
> +{
> + CPUState *some_cpu;
> + int cpu_index = 0;
> +
> + cpu_index_auto_assigned = true;
> + CPU_FOREACH(some_cpu) {
> + cpu_index++;
> + }
> + return cpu_index;
> +}
I see this is code moved from elsewhere but I feel a little comment
about this should probably accompany the variable. I think it means once
you have added a CPU without an explicit index all future CPUs will be
auto assigned and you can no longer add CPUs with a specific index?
Does this mean you can't hotplug additional CPUs without having
specified a CPU topology at start-up?
> +
> +void cpu_list_add(CPUState *cpu)
> +{
> + qemu_mutex_lock(&qemu_cpu_list_mutex);
> + if (cpu->cpu_index == UNASSIGNED_CPU_INDEX) {
> + cpu->cpu_index = cpu_get_free_index();
> + assert(cpu->cpu_index != UNASSIGNED_CPU_INDEX);
> + } else {
> + assert(!cpu_index_auto_assigned);
> + }
> + QTAILQ_INSERT_TAIL(&cpus, cpu, node);
> + qemu_mutex_unlock(&qemu_cpu_list_mutex);
> +}
> +
> +void cpu_list_remove(CPUState *cpu)
> +{
> + qemu_mutex_lock(&qemu_cpu_list_mutex);
> + if (!QTAILQ_IN_USE(cpu, node)) {
> + /* there is nothing to undo since cpu_exec_init() hasn't been called
> */
> + qemu_mutex_unlock(&qemu_cpu_list_mutex);
> + return;
> + }
> +
> + assert(!(cpu_index_auto_assigned && cpu != QTAILQ_LAST(&cpus,
> CPUTailQ)));
> +
> + QTAILQ_REMOVE(&cpus, cpu, node);
> + cpu->cpu_index = UNASSIGNED_CPU_INDEX;
> + qemu_mutex_unlock(&qemu_cpu_list_mutex);
> +}
> diff --git a/exec.c b/exec.c
> index ce3fb9e..784990c 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -598,36 +598,11 @@ AddressSpace *cpu_get_address_space(CPUState *cpu, int
> asidx)
> }
> #endif
>
> -static bool cpu_index_auto_assigned;
> -
> -static int cpu_get_free_index(void)
> -{
> - CPUState *some_cpu;
> - int cpu_index = 0;
> -
> - cpu_index_auto_assigned = true;
> - CPU_FOREACH(some_cpu) {
> - cpu_index++;
> - }
> - return cpu_index;
> -}
> -
> void cpu_exec_exit(CPUState *cpu)
> {
> CPUClass *cc = CPU_GET_CLASS(cpu);
>
> - cpu_list_lock();
> - if (!QTAILQ_IN_USE(cpu, node)) {
> - /* there is nothing to undo since cpu_exec_init() hasn't been called
> */
> - cpu_list_unlock();
> - return;
> - }
> -
> - assert(!(cpu_index_auto_assigned && cpu != QTAILQ_LAST(&cpus,
> CPUTailQ)));
> -
> - QTAILQ_REMOVE(&cpus, cpu, node);
> - cpu->cpu_index = UNASSIGNED_CPU_INDEX;
> - cpu_list_unlock();
> + cpu_list_remove(cpu);
>
> if (cc->vmsd != NULL) {
> vmstate_unregister(NULL, cc->vmsd, cpu);
> @@ -663,15 +638,7 @@ void cpu_exec_init(CPUState *cpu, Error **errp)
> object_ref(OBJECT(cpu->memory));
> #endif
>
> - cpu_list_lock();
> - if (cpu->cpu_index == UNASSIGNED_CPU_INDEX) {
> - cpu->cpu_index = cpu_get_free_index();
> - assert(cpu->cpu_index != UNASSIGNED_CPU_INDEX);
> - } else {
> - assert(!cpu_index_auto_assigned);
> - }
> - QTAILQ_INSERT_TAIL(&cpus, cpu, node);
> - cpu_list_unlock();
> + cpu_list_add(cpu);
>
> #ifndef CONFIG_USER_ONLY
> if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
> diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
> index b6a7059..c694d16 100644
> --- a/include/exec/cpu-all.h
> +++ b/include/exec/cpu-all.h
> @@ -187,6 +187,10 @@ void address_space_stq(AddressSpace *as, hwaddr addr,
> uint64_t val,
> MemTxAttrs attrs, MemTxResult *result);
> #endif
>
> +/* The CPU list lock nests outside tb_lock/tb_unlock. */
> +void cpu_list_lock(void);
> +void cpu_list_unlock(void);
> +
> /* page related stuff */
>
> #define TARGET_PAGE_SIZE (1 << TARGET_PAGE_BITS)
> diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
> index 952bcfe..1d41452 100644
> --- a/include/exec/cpu-common.h
> +++ b/include/exec/cpu-common.h
> @@ -23,6 +23,8 @@ typedef struct CPUListState {
> FILE *file;
> } CPUListState;
>
> +void qemu_init_cpu_list(void);
> +
> #if !defined(CONFIG_USER_ONLY)
>
> enum device_endian {
> diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
> index a0e87be..36ab8b6 100644
> --- a/include/exec/exec-all.h
> +++ b/include/exec/exec-all.h
> @@ -56,17 +56,6 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
> target_ulong pc, target_ulong cs_base,
> uint32_t flags,
> int cflags);
> -#if defined(CONFIG_USER_ONLY)
> -void cpu_list_lock(void);
> -void cpu_list_unlock(void);
> -#else
> -static inline void cpu_list_unlock(void)
> -{
> -}
> -static inline void cpu_list_lock(void)
> -{
> -}
> -#endif
>
> void cpu_exec_init(CPUState *cpu, Error **errp);
> void QEMU_NORETURN cpu_loop_exit(CPUState *cpu);
> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> index 4aa9e61..ea3233f 100644
> --- a/include/qom/cpu.h
> +++ b/include/qom/cpu.h
> @@ -545,6 +545,18 @@ static inline int cpu_asidx_from_attrs(CPUState *cpu,
> MemTxAttrs attrs)
> #endif
>
> /**
> + * cpu_list_add:
> + * @cpu: The CPU to be added to the list of CPUs.
> + */
> +void cpu_list_add(CPUState *cpu);
> +
> +/**
> + * cpu_list_remove:
> + * @cpu: The CPU to be removed from the list of CPUs.
> + */
> +void cpu_list_remove(CPUState *cpu);
> +
> +/**
> * cpu_reset:
> * @cpu: The CPU whose state is to be reset.
> */
> diff --git a/linux-user/main.c b/linux-user/main.c
> index 0f24d57..c3fefb6 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -111,7 +111,6 @@ int cpu_get_pic_interrupt(CPUX86State *env)
> We don't require a full sync, only that no cpus are executing guest code.
> The alternative is to map target atomic ops onto host equivalents,
> which requires quite a lot of per host/target work. */
> -static QemuMutex cpu_list_mutex;
> static QemuMutex exclusive_lock;
> static QemuCond exclusive_cond;
> static QemuCond exclusive_resume;
> @@ -119,7 +118,6 @@ static int pending_cpus;
>
> void qemu_init_cpu_loop(void)
> {
> - qemu_mutex_init(&cpu_list_mutex);
> qemu_mutex_init(&exclusive_lock);
> qemu_cond_init(&exclusive_cond);
> qemu_cond_init(&exclusive_resume);
> @@ -128,6 +126,7 @@ void qemu_init_cpu_loop(void)
> /* Make sure everything is in a consistent state for calling fork(). */
> void fork_start(void)
> {
> + cpu_list_lock();
> qemu_mutex_lock(&tcg_ctx.tb_ctx.tb_lock);
> qemu_mutex_lock(&exclusive_lock);
> mmap_fork_start();
> @@ -147,14 +146,15 @@ void fork_end(int child)
> }
> pending_cpus = 0;
> qemu_mutex_init(&exclusive_lock);
> - qemu_mutex_init(&cpu_list_mutex);
> qemu_cond_init(&exclusive_cond);
> qemu_cond_init(&exclusive_resume);
> qemu_mutex_init(&tcg_ctx.tb_ctx.tb_lock);
> + qemu_init_cpu_list();
> gdbserver_fork(thread_cpu);
> } else {
> qemu_mutex_unlock(&exclusive_lock);
> qemu_mutex_unlock(&tcg_ctx.tb_ctx.tb_lock);
> + cpu_list_unlock();
> }
> }
>
> @@ -221,16 +221,6 @@ static inline void cpu_exec_end(CPUState *cpu)
> qemu_mutex_unlock(&exclusive_lock);
> }
>
> -void cpu_list_lock(void)
> -{
> - qemu_mutex_lock(&cpu_list_mutex);
> -}
> -
> -void cpu_list_unlock(void)
> -{
> - qemu_mutex_unlock(&cpu_list_mutex);
> -}
> -
>
> #ifdef TARGET_I386
> /***********************************************************/
> @@ -4229,6 +4219,7 @@ int main(int argc, char **argv, char **envp)
> int ret;
> int execfd;
>
> + qemu_init_cpu_list();
> qemu_init_cpu_loop();
> module_call_init(MODULE_INIT_QOM);
>
> diff --git a/vl.c b/vl.c
> index ee557a1..7b1b04a 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2978,6 +2978,7 @@ int main(int argc, char **argv, char **envp)
> Error *err = NULL;
> bool list_data_dirs = false;
>
> + qemu_init_cpu_list();
> qemu_init_cpu_loop();
> qemu_mutex_lock_iothread();
Otherwise:
Reviewed-by: Alex Bennée <alex.ben...@linaro.org>
--
Alex Bennée
