From bd846c5d583a63eaaf836403515c4bf3748f3bb3 Mon Sep 17 00:00:00 2001 From: "Maciej S. Szmigiero" Date: Tue, 4 Mar 2025 23:03:46 +0100 Subject: [PATCH] vfio/migration: Convert bytes_transferred counter to atomic MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Maciej S. Szmigiero Link: https://lore.kernel.org/qemu-devel/dc391771d2d9ad0f311994f0cb9e666da564aeaf.1741124640.git.maciej.szmigiero@oracle.com Signed-off-by: Cédric Le Goater --- hw/vfio/migration.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index 03890eaa48..5532787be6 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -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); } /* -- 2.30.2