From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>

Wire data commonly use BE byte order (including in the existing migration
protocol), use it also for for VFIO device state packets.

This will allow VFIO multifd device state transfer between hosts with
different endianness.
Although currently there is no such use case, it's good to have it now
for completeness.

Reviewed-by: Avihai Horon <avihaih@nvidia.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
---
 hw/vfio/migration-multifd.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c
index a9d41b9f1cb1..e816461e1652 100644
--- a/hw/vfio/migration-multifd.c
+++ b/hw/vfio/migration-multifd.c
@@ -13,6 +13,7 @@
 #include "hw/vfio/vfio-common.h"
 #include "migration/misc.h"
 #include "qapi/error.h"
+#include "qemu/bswap.h"
 #include "qemu/error-report.h"
 #include "qemu/lockable.h"
 #include "qemu/main-loop.h"
@@ -208,12 +209,16 @@ bool vfio_multifd_load_state_buffer(void *opaque, char *data, size_t data_size,
         return false;
     }
 
+    packet->version = be32_to_cpu(packet->version);
     if (packet->version != VFIO_DEVICE_STATE_PACKET_VER_CURRENT) {
         error_setg(errp, "%s: packet has unknown version %" PRIu32,
                    vbasedev->name, packet->version);
         return false;
     }
 
+    packet->idx = be32_to_cpu(packet->idx);
+    packet->flags = be32_to_cpu(packet->flags);
+
     if (packet->idx == UINT32_MAX) {
         error_setg(errp, "%s: packet index is invalid", vbasedev->name);
         return false;
@@ -682,9 +687,9 @@ vfio_save_complete_precopy_thread_config_state(VFIODevice *vbasedev,
 
     packet_len = sizeof(*packet) + bioc->usage;
     packet = g_malloc0(packet_len);
-    packet->version = VFIO_DEVICE_STATE_PACKET_VER_CURRENT;
-    packet->idx = idx;
-    packet->flags = VFIO_DEVICE_STATE_CONFIG_STATE;
+    packet->version = cpu_to_be32(VFIO_DEVICE_STATE_PACKET_VER_CURRENT);
+    packet->idx = cpu_to_be32(idx);
+    packet->flags = cpu_to_be32(VFIO_DEVICE_STATE_CONFIG_STATE);
     memcpy(&packet->data, bioc->data, bioc->usage);
 
     if (!multifd_queue_device_state(idstr, instance_id,
@@ -734,7 +739,7 @@ vfio_multifd_save_complete_precopy_thread(SaveLiveCompletePrecopyThreadData *d,
     }
 
     packet = g_malloc0(sizeof(*packet) + migration->data_buffer_size);
-    packet->version = VFIO_DEVICE_STATE_PACKET_VER_CURRENT;
+    packet->version = cpu_to_be32(VFIO_DEVICE_STATE_PACKET_VER_CURRENT);
 
     for (idx = 0; ; idx++) {
         ssize_t data_size;
@@ -755,7 +760,7 @@ vfio_multifd_save_complete_precopy_thread(SaveLiveCompletePrecopyThreadData *d,
             break;
         }
 
-        packet->idx = idx;
+        packet->idx = cpu_to_be32(idx);
         packet_size = sizeof(*packet) + data_size;
 
         if (!multifd_queue_device_state(d->idstr, d->instance_id,

On 3/10/25 13:53, Maciej S. Szmigiero wrote:
> From: "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>
> 
> Wire data commonly use BE byte order (including in the existing migration
> protocol), use it also for for VFIO device state packets.
> 
> This will allow VFIO multifd device state transfer between hosts with
> different endianness.
> Although currently there is no such use case, it's good to have it now
> for completeness.
> 
> Reviewed-by: Avihai Horon <avihaih@nvidia.com>
> Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
> --->   hw/vfio/migration-multifd.c | 15 ++++++++++-----
>   1 file changed, 10 insertions(+), 5 deletions(-)



Applied to vfio-next.

Thanks,

C.



  
> diff --git a/hw/vfio/migration-multifd.c b/hw/vfio/migration-multifd.c
> index a9d41b9f1cb1..e816461e1652 100644
> --- a/hw/vfio/migration-multifd.c
> +++ b/hw/vfio/migration-multifd.c
> @@ -13,6 +13,7 @@
>   #include "hw/vfio/vfio-common.h"
>   #include "migration/misc.h"
>   #include "qapi/error.h"
> +#include "qemu/bswap.h"
>   #include "qemu/error-report.h"
>   #include "qemu/lockable.h"
>   #include "qemu/main-loop.h"
> @@ -208,12 +209,16 @@ bool vfio_multifd_load_state_buffer(void *opaque, char *data, size_t data_size,
>           return false;
>       }
>   
> +    packet->version = be32_to_cpu(packet->version);
>       if (packet->version != VFIO_DEVICE_STATE_PACKET_VER_CURRENT) {
>           error_setg(errp, "%s: packet has unknown version %" PRIu32,
>                      vbasedev->name, packet->version);
>           return false;
>       }
>   
> +    packet->idx = be32_to_cpu(packet->idx);
> +    packet->flags = be32_to_cpu(packet->flags);
> +
>       if (packet->idx == UINT32_MAX) {
>           error_setg(errp, "%s: packet index is invalid", vbasedev->name);
>           return false;
> @@ -682,9 +687,9 @@ vfio_save_complete_precopy_thread_config_state(VFIODevice *vbasedev,
>   
>       packet_len = sizeof(*packet) + bioc->usage;
>       packet = g_malloc0(packet_len);
> -    packet->version = VFIO_DEVICE_STATE_PACKET_VER_CURRENT;
> -    packet->idx = idx;
> -    packet->flags = VFIO_DEVICE_STATE_CONFIG_STATE;
> +    packet->version = cpu_to_be32(VFIO_DEVICE_STATE_PACKET_VER_CURRENT);
> +    packet->idx = cpu_to_be32(idx);
> +    packet->flags = cpu_to_be32(VFIO_DEVICE_STATE_CONFIG_STATE);
>       memcpy(&packet->data, bioc->data, bioc->usage);
>   
>       if (!multifd_queue_device_state(idstr, instance_id,
> @@ -734,7 +739,7 @@ vfio_multifd_save_complete_precopy_thread(SaveLiveCompletePrecopyThreadData *d,
>       }
>   
>       packet = g_malloc0(sizeof(*packet) + migration->data_buffer_size);
> -    packet->version = VFIO_DEVICE_STATE_PACKET_VER_CURRENT;
> +    packet->version = cpu_to_be32(VFIO_DEVICE_STATE_PACKET_VER_CURRENT);
>   
>       for (idx = 0; ; idx++) {
>           ssize_t data_size;
> @@ -755,7 +760,7 @@ vfio_multifd_save_complete_precopy_thread(SaveLiveCompletePrecopyThreadData *d,
>               break;
>           }
>   
> -        packet->idx = idx;
> +        packet->idx = cpu_to_be32(idx);
>           packet_size = sizeof(*packet) + data_size;
>   
>           if (!multifd_queue_device_state(d->idstr, d->instance_id,
>