From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56115) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bn5sr-0003jd-Fd for qemu-devel@nongnu.org; Thu, 22 Sep 2016 11:26:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bn5sn-0002JA-3L for qemu-devel@nongnu.org; Thu, 22 Sep 2016 11:25:56 -0400 Received: from mail-wm0-f46.google.com ([74.125.82.46]:38675) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bn5sm-0002J1-QM for qemu-devel@nongnu.org; Thu, 22 Sep 2016 11:25:53 -0400 Received: by mail-wm0-f46.google.com with SMTP id l132so154218385wmf.1 for ; Thu, 22 Sep 2016 08:25:52 -0700 (PDT) References: <1473678761-8885-1-git-send-email-pbonzini@redhat.com> <1473678761-8885-7-git-send-email-pbonzini@redhat.com> From: Alex =?utf-8?Q?Benn=C3=A9e?= In-reply-to: <1473678761-8885-7-git-send-email-pbonzini@redhat.com> Date: Thu, 22 Sep 2016 16:24:50 +0100 Message-ID: <87bmzgarel.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH 06/16] cpus-common: move CPU list management to common code List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: qemu-devel@nongnu.org, sergey.fedorov@linaro.org Paolo Bonzini 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 > --- > 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 . > + */ > + > +#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 Bennée