[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v3 2/4] exec: Protect map_client_list with mutex
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH v3 2/4] exec: Protect map_client_list with mutex |
Date: |
Mon, 16 Mar 2015 08:33:01 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 |
On 16/03/2015 06:31, Fam Zheng wrote:
> So that accesses from multiple threads are safe.
>
> Signed-off-by: Fam Zheng <address@hidden>
> ---
> exec.c | 24 +++++++++++++++---------
> 1 file changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index 4080044..3e54580 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -429,15 +429,6 @@ address_space_translate_for_iotlb(CPUState *cpu, hwaddr
> addr,
> }
> #endif
>
> -void cpu_exec_init_all(void)
> -{
> -#if !defined(CONFIG_USER_ONLY)
> - qemu_mutex_init(&ram_list.mutex);
> - memory_map_init();
> - io_mem_init();
> -#endif
> -}
> -
> #if !defined(CONFIG_USER_ONLY)
>
> static int cpu_common_post_load(void *opaque, int version_id)
> @@ -2494,6 +2485,7 @@ typedef struct MapClient {
> QLIST_ENTRY(MapClient) link;
> } MapClient;
>
> +QemuMutex map_client_list_lock;
> static QLIST_HEAD(map_client_list, MapClient) map_client_list
> = QLIST_HEAD_INITIALIZER(map_client_list);
>
> @@ -2501,12 +2493,24 @@ void *cpu_register_map_client(void *opaque, void
> (*callback)(void *opaque))
> {
> MapClient *client = g_malloc(sizeof(*client));
>
> + qemu_mutex_lock(&map_client_list_lock);
> client->opaque = opaque;
> client->callback = callback;
> QLIST_INSERT_HEAD(&map_client_list, client, link);
> + qemu_mutex_unlock(&map_client_list_lock);
> return client;
> }
>
> +void cpu_exec_init_all(void)
> +{
> +#if !defined(CONFIG_USER_ONLY)
> + qemu_mutex_init(&ram_list.mutex);
> + memory_map_init();
> + io_mem_init();
> +#endif
> + qemu_mutex_init(&map_client_list_lock);
> +}
> +
You are moving cpu_exec_init_all within an #ifndef CONFIG_USER_ONLY.
Does this patch compile for user-mode emulation?
The move itself is okay but only if you remove the two calls in
*-user/main.c (and possibly move the prototype to include/exec/exec-all.h).
> static void cpu_unregister_map_client(void *_client)
> {
> MapClient *client = (MapClient *)_client;
> @@ -2519,11 +2523,13 @@ static void cpu_notify_map_clients(void)
> {
> MapClient *client;
>
> + qemu_mutex_lock(&map_client_list_lock);
> while (!QLIST_EMPTY(&map_client_list)) {
> client = QLIST_FIRST(&map_client_list);
> client->callback(client->opaque);
A good rule of thumb is never hold a lock while calling "unknown" code.
This will be fixed in patch 4, so it's okay.
Paolo
> cpu_unregister_map_client(client);
> }
> + qemu_mutex_unlock(&map_client_list_lock);
> }
>
> bool address_space_access_valid(AddressSpace *as, hwaddr addr, int len, bool
> is_write)
>