vfio/migration: Convert bytes_transferred counter to atomic

So it can be safety accessed from multiple threads.

This variable type needs to be changed to unsigned long since
32-bit host platforms lack the necessary addition atomics on 64-bit
variables.

Using 32-bit counters on 32-bit host platforms should not be a problem
in practice since they can't realistically address more memory anyway.

Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/dc391771d2d9ad0f311994f0cb9e666da564aeaf.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
This commit is contained in:
Maciej S. Szmigiero 2025-03-04 23:03:46 +01:00 committed by Cédric Le Goater
parent 5963c219a0
commit bd846c5d58

View file

@ -55,7 +55,7 @@
*/
#define VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE (1 * MiB)
static int64_t bytes_transferred;
static unsigned long bytes_transferred;
static const char *mig_state_to_str(enum vfio_device_mig_state state)
{
@ -391,7 +391,7 @@ static ssize_t vfio_save_block(QEMUFile *f, VFIOMigration *migration)
qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE);
qemu_put_be64(f, data_size);
qemu_put_buffer(f, migration->data_buffer, data_size);
bytes_transferred += data_size;
qatomic_add(&bytes_transferred, data_size);
trace_vfio_save_block(migration->vbasedev->name, data_size);
@ -1013,12 +1013,12 @@ static int vfio_block_migration(VFIODevice *vbasedev, Error *err, Error **errp)
int64_t vfio_mig_bytes_transferred(void)
{
return bytes_transferred;
return MIN(qatomic_read(&bytes_transferred), INT64_MAX);
}
void vfio_reset_bytes_transferred(void)
{
bytes_transferred = 0;
qatomic_set(&bytes_transferred, 0);
}
/*