Re: [Qemu-devel] [PATCH v3 01/35] cpu-exec: Migrate some generic fns to cpu-exec-common

[Paolo Bonzini]

On 18/07/2015 11:40, Peter Crosthwaite wrote:
> The goal is to split the functions such that cpu-exec is CPU specific
> content, while cpus-exec-common.c is generic code only. The function
> interface to cpu-exec needs to be virtualised to prepare support for
> multi-arch and moving these definitions out saves bloating the QOM
> interface. So move these definitions out of cpu-exec to a new module,
> cpu-exec-common.
> 
> Signed-off-by: Peter Crosthwaite <address@hidden>
> ---
> Changed since RFCv2
> Make a new file instead of move stuff to cpus.c
> ---
>  Makefile.target   |  1 +
>  cpu-exec-common.c | 76 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  cpu-exec.c        | 49 -----------------------------------
>  3 files changed, 77 insertions(+), 49 deletions(-)
>  create mode 100644 cpu-exec-common.c
> 
> diff --git a/Makefile.target b/Makefile.target
> index 3e7aafd..6435c96 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -85,6 +85,7 @@ all: $(PROGS) stap
>  #########################################################
>  # cpu emulator library
>  obj-y = exec.o translate-all.o cpu-exec.o
> +obj-y += cpu-exec-common.o
>  obj-y += tcg/tcg.o tcg/tcg-op.o tcg/optimize.o
>  obj-$(CONFIG_TCG_INTERPRETER) += tci.o
>  obj-$(CONFIG_TCG_INTERPRETER) += disas/tci.o
> diff --git a/cpu-exec-common.c b/cpu-exec-common.c
> new file mode 100644
> index 0000000..3d87c59
> --- /dev/null
> +++ b/cpu-exec-common.c
> @@ -0,0 +1,76 @@
> +/*
> + *  emulator main execution loop
> + *
> + *  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 "config.h"
> +#include "cpu.h"
> +#include "sysemu/cpus.h"
> +#include "exec/memory-internal.h"
> +
> +volatile sig_atomic_t exit_request;
> +
> +/* exit the current TB from a signal handler. The host registers are
> +   restored in a state compatible with the CPU emulator
> + */
> +#if defined(CONFIG_SOFTMMU)
> +void cpu_resume_from_signal(CPUState *cpu, void *puc)
> +{
> +    /* XXX: restore cpu registers saved in host registers */
> +
> +    cpu->exception_index = -1;
> +    siglongjmp(cpu->jmp_env, 1);
> +}
> +
> +void cpu_reload_memory_map(CPUState *cpu)
> +{
> +    AddressSpaceDispatch *d;
> +
> +    if (qemu_in_vcpu_thread()) {
> +        /* Do not let the guest prolong the critical section as much as it
> +         * as it desires.
> +         *
> +         * Currently, this is prevented by the I/O thread's periodinc kicking
> +         * of the VCPU thread (iothread_requesting_mutex, 
> qemu_cpu_kick_thread)
> +         * but this will go away once TCG's execution moves out of the global
> +         * mutex.
> +         *
> +         * This pair matches cpu_exec's rcu_read_lock()/rcu_read_unlock(), 
> which
> +         * only protects cpu->as->dispatch.  Since we reload it below, we can
> +         * split the critical section.
> +         */
> +        rcu_read_unlock();
> +        rcu_read_lock();
> +    }
> +
> +    /* The CPU and TLB are protected by the iothread lock.  */
> +    d = atomic_rcu_read(&cpu->as->dispatch);
> +    cpu->memory_dispatch = d;
> +    CPU_HOOK(cpu, tlb_flush)(cpu, 1);

CPU_HOOK is not defined yet at this point.

Paolo

> +}
> +#endif
> +
> +void cpu_loop_exit(CPUState *cpu)
> +{
> +    cpu->current_tb = NULL;
> +    siglongjmp(cpu->jmp_env, 1);
> +}
> +
> +typedef struct CPUListFn {
> +    void (*do_cpu_list)(FILE *f, fprintf_function cpu_fprintf);
> +    QLIST_ENTRY(CPUListFn) list;
> +} CPUListFn;
> diff --git a/cpu-exec.c b/cpu-exec.c
> index 75694f3..14ea6fc 100644
> --- a/cpu-exec.c
> +++ b/cpu-exec.c
> @@ -25,7 +25,6 @@
>  #include "sysemu/qtest.h"
>  #include "qemu/timer.h"
>  #include "exec/address-spaces.h"
> -#include "exec/memory-internal.h"
>  #include "qemu/rcu.h"
>  #include "exec/tb-hash.h"
>  
> @@ -128,52 +127,6 @@ static void init_delay_params(SyncClocks *sc, const 
> CPUState *cpu)
>  }
>  #endif /* CONFIG USER ONLY */
>  
> -void cpu_loop_exit(CPUState *cpu)
> -{
> -    cpu->current_tb = NULL;
> -    siglongjmp(cpu->jmp_env, 1);
> -}
> -
> -/* exit the current TB from a signal handler. The host registers are
> -   restored in a state compatible with the CPU emulator
> - */
> -#if defined(CONFIG_SOFTMMU)
> -void cpu_resume_from_signal(CPUState *cpu, void *puc)
> -{
> -    /* XXX: restore cpu registers saved in host registers */
> -
> -    cpu->exception_index = -1;
> -    siglongjmp(cpu->jmp_env, 1);
> -}
> -
> -void cpu_reload_memory_map(CPUState *cpu)
> -{
> -    AddressSpaceDispatch *d;
> -
> -    if (qemu_in_vcpu_thread()) {
> -        /* Do not let the guest prolong the critical section as much as it
> -         * as it desires.
> -         *
> -         * Currently, this is prevented by the I/O thread's periodinc kicking
> -         * of the VCPU thread (iothread_requesting_mutex, 
> qemu_cpu_kick_thread)
> -         * but this will go away once TCG's execution moves out of the global
> -         * mutex.
> -         *
> -         * This pair matches cpu_exec's rcu_read_lock()/rcu_read_unlock(), 
> which
> -         * only protects cpu->as->dispatch.  Since we reload it below, we can
> -         * split the critical section.
> -         */
> -        rcu_read_unlock();
> -        rcu_read_lock();
> -    }
> -
> -    /* The CPU and TLB are protected by the iothread lock.  */
> -    d = atomic_rcu_read(&cpu->as->dispatch);
> -    cpu->memory_dispatch = d;
> -    tlb_flush(cpu, 1);
> -}
> -#endif
> -
>  /* Execute a TB, and fix up the CPU state afterwards if necessary */
>  static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, uint8_t *tb_ptr)
>  {
> @@ -345,8 +298,6 @@ static void cpu_handle_debug_exception(CPUState *cpu)
>  
>  /* main execution loop */
>  
> -volatile sig_atomic_t exit_request;
> -
>  int cpu_exec(CPUState *cpu)
>  {
>      CPUClass *cc = CPU_GET_CLASS(cpu);
>