Il 11/04/2013 14:14, Benoît Canet ha scritto:
> The function used to wait is registered as a pre migration flush hook.
>
> The completion status is put in the virtio ring buffer which
> will be send to the guest on resume by the viring migration code
>
> This patch is a rewrite from the one written by Aneesh Kumar.
>
> Signed-off-by: Benoit Canet <ben...@irqsave.net>
> ---
> hw/9pfs/virtio-9p-device.c | 2 ++
> hw/9pfs/virtio-9p.c | 70
> ++++++++++++++++++++++++++++++++++++++++++++
> hw/9pfs/virtio-9p.h | 2 ++
> 3 files changed, 74 insertions(+)
>
> diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> index 7d4aefd..02b8630 100644
> --- a/hw/9pfs/virtio-9p-device.c
> +++ b/hw/9pfs/virtio-9p-device.c
> @@ -200,6 +200,8 @@ VirtIODevice *virtio_9p_init(DeviceState *dev, V9fsConf
> *conf)
> V9fsPath path;
> static int virtio_9p_id;
>
> + v9fs_init_migration_helper();
> +
> s = (V9fsState *)virtio_common_init("virtio-9p",
> VIRTIO_ID_9P,
> sizeof(struct virtio_9p_config)+
> diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
> index 5cc4c92..3bf3ee4 100644
> --- a/hw/9pfs/virtio-9p.c
> +++ b/hw/9pfs/virtio-9p.c
> @@ -20,11 +20,20 @@
> #include "virtio-9p-coth.h"
> #include "trace.h"
> #include "migration/migration.h"
> +#include "migration/migration-flush-hooks.h"
>
> int open_fd_hw;
> int total_open_fd;
> static int open_fd_rc;
>
> +typedef struct MigrationHelper {
> + int32_t pending_requests;
> + QemuCond complete;
> + QemuMutex mutex;
> +} MigrationHelper;
> +
> +MigrationHelper *migration;
I say, just use three variables instead of a struct.
Paolo
> enum {
> Oread = 0x00,
> Owrite = 0x01,
> @@ -37,6 +46,62 @@ enum {
> Oappend = 0x80,
> };
>
> +static void v9fs_wait_for_requests_drain(void)
> +{
> + if (!migration) {
> + return;
> + }
> +
> + qemu_mutex_lock(&migration->mutex);
> + while (migration->pending_requests) {
> + /* At this point ticks and vcpus will be stopped so we can safely
> + * release the BQL so pending 9p callbacks will be executed and the
> + * condition signaled.
> + */
> + qemu_mutex_unlock_iothread();
> + qemu_cond_wait(&migration->complete, &migration->mutex);
> + qemu_mutex_lock_iothread();
> + }
> + qemu_mutex_unlock(&migration->mutex);
> +}
> +
> +void v9fs_init_migration_helper(void)
> +{
> + if (migration) {
> + return;
> + }
> +
> + migration = g_new0(MigrationHelper, 1);
> + qemu_mutex_init(&migration->mutex);
> + qemu_cond_init(&migration->complete);
> + register_migration_flush_hook(v9fs_wait_for_requests_drain);
> +}
> +
> +static void v9fs_inc_pending_requests(void)
> +{
> + if (!migration) {
> + return;
> + }
> +
> + qemu_mutex_lock(&migration->mutex);
> + migration->pending_requests++;
> + qemu_mutex_unlock(&migration->mutex);
> +}
> +
> +static void v9fs_dec_pending_requests(void)
> +{
> + if (!migration) {
> + return;
> + }
> +
> + qemu_mutex_lock(&migration->mutex);
> + migration->pending_requests--;
> + if (!migration->pending_requests) {
> + qemu_cond_signal(&migration->complete);
> + }
> + qemu_mutex_unlock(&migration->mutex);
> +}
> +
> static int omode_to_uflags(int8_t mode)
> {
> int ret = 0;
> @@ -637,6 +702,8 @@ static void complete_pdu(V9fsState *s, V9fsPDU *pdu,
> ssize_t len)
> qemu_co_queue_next(&pdu->complete);
>
> free_pdu(s, pdu);
> +
> + v9fs_dec_pending_requests();
> }
>
> static mode_t v9mode_to_mode(uint32_t mode, V9fsString *extension)
> @@ -3240,6 +3307,9 @@ static void submit_pdu(V9fsState *s, V9fsPDU *pdu)
> if (is_ro_export(&s->ctx) && !is_read_only_op(pdu)) {
> handler = v9fs_fs_ro;
> }
> +
> + v9fs_inc_pending_requests();
> +
> co = qemu_coroutine_create(handler);
> qemu_coroutine_enter(co, pdu);
> }
> diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
> index 52b1c69..4d16d46 100644
> --- a/hw/9pfs/virtio-9p.h
> +++ b/hw/9pfs/virtio-9p.h
> @@ -401,4 +401,6 @@ extern int v9fs_name_to_path(V9fsState *s, V9fsPath
> *dirpath,
> #define pdu_unmarshal(pdu, offset, fmt, args...) \
> v9fs_unmarshal(pdu->elem.out_sg, pdu->elem.out_num, offset, 1, fmt,
> ##args)
>
> +void v9fs_init_migration_helper(void);
> +
> #endif
>
