diff mbox series

[for-8.2,6/6] vfio/migration: Allow migration of multiple P2P supporting devices

Message ID 20230716081541.27900-7-avihaih@nvidia.com
State New
Headers show
Series vfio/migration: Add P2P support for VFIO migration | expand

Commit Message

Avihai Horon July 16, 2023, 8:15 a.m. UTC 
Now that P2P support has been added to VFIO migration, allow migration
of multiple devices if all of them support P2P migration.

Single device migration is allowed regardless of P2P migration support.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
 hw/vfio/common.c | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

Comments

Cédric Le Goater July 21, 2023, 12:09 p.m. UTC | #1 
On 7/16/23 10:15, Avihai Horon wrote:
> Now that P2P support has been added to VFIO migration, allow migration
> of multiple devices if all of them support P2P migration.
> 
> Single device migration is allowed regardless of P2P migration support.
> 
> Signed-off-by: Avihai Horon <avihaih@nvidia.com>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>   hw/vfio/common.c | 26 ++++++++++++++++++--------
>   1 file changed, 18 insertions(+), 8 deletions(-)
> 
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index 7c3d636025..753b320739 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -363,21 +363,31 @@ bool vfio_mig_active(void)
>   
>   static Error *multiple_devices_migration_blocker;
>   
> -static unsigned int vfio_migratable_device_num(void)
> +/*
> + * Multiple devices migration is allowed only if all devices support P2P
> + * migration. Single device migration is allowed regardless of P2P migration
> + * support.
> + */
> +static bool vfio_should_block_multiple_devices_migration(void)

Could we revert the logic and call the routine :

   vfio_multiple_devices_migration_is_supported()

I think it would be clearer in the callers.  This is minor.

Thanks,

C.

>   {
>       VFIOGroup *group;
>       VFIODevice *vbasedev;
>       unsigned int device_num = 0;
> +    bool all_support_p2p = true;
>   
>       QLIST_FOREACH(group, &vfio_group_list, next) {
>           QLIST_FOREACH(vbasedev, &group->device_list, next) {
>               if (vbasedev->migration) {
>                   device_num++;
> +
> +                if (!(vbasedev->migration->mig_flags & VFIO_MIGRATION_P2P)) {
> +                    all_support_p2p = false;
> +                }
>               }
>           }
>       }
>   
> -    return device_num;
> +    return !all_support_p2p && device_num > 1;
>   }
>   
>   int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error **errp)
> @@ -385,19 +395,19 @@ int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error **errp)
>       int ret;
>   
>       if (multiple_devices_migration_blocker ||
> -        vfio_migratable_device_num() <= 1) {
> +        !vfio_should_block_multiple_devices_migration()) {
>           return 0;
>       }
>   
>       if (vbasedev->enable_migration == ON_OFF_AUTO_ON) {
> -        error_setg(errp, "Migration is currently not supported with multiple "
> -                         "VFIO devices");
> +        error_setg(errp, "Multiple VFIO devices migration is supported only if "
> +                         "all of them support P2P migration");
>           return -EINVAL;
>       }
>   
>       error_setg(&multiple_devices_migration_blocker,
> -               "Migration is currently not supported with multiple "
> -               "VFIO devices");
> +               "Multiple VFIO devices migration is supported only if all of "
> +               "them support P2P migration");
>       ret = migrate_add_blocker(multiple_devices_migration_blocker, errp);
>       if (ret < 0) {
>           error_free(multiple_devices_migration_blocker);
> @@ -410,7 +420,7 @@ int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error **errp)
>   void vfio_unblock_multiple_devices_migration(void)
>   {
>       if (!multiple_devices_migration_blocker ||
> -        vfio_migratable_device_num() > 1) {
> +        vfio_should_block_multiple_devices_migration()) {
>           return;
>       }
>
Avihai Horon July 23, 2023, 10:42 a.m. UTC | #2 
On 21/07/2023 15:09, Cédric Le Goater wrote:
> External email: Use caution opening links or attachments
>
>
> On 7/16/23 10:15, Avihai Horon wrote:
>> Now that P2P support has been added to VFIO migration, allow migration
>> of multiple devices if all of them support P2P migration.
>>
>> Single device migration is allowed regardless of P2P migration support.
>>
>> Signed-off-by: Avihai Horon <avihaih@nvidia.com>
>> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
>> ---
>>   hw/vfio/common.c | 26 ++++++++++++++++++--------
>>   1 file changed, 18 insertions(+), 8 deletions(-)
>>
>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>> index 7c3d636025..753b320739 100644
>> --- a/hw/vfio/common.c
>> +++ b/hw/vfio/common.c
>> @@ -363,21 +363,31 @@ bool vfio_mig_active(void)
>>
>>   static Error *multiple_devices_migration_blocker;
>>
>> -static unsigned int vfio_migratable_device_num(void)
>> +/*
>> + * Multiple devices migration is allowed only if all devices support 
>> P2P
>> + * migration. Single device migration is allowed regardless of P2P 
>> migration
>> + * support.
>> + */
>> +static bool vfio_should_block_multiple_devices_migration(void)
>
> Could we revert the logic and call the routine :
>
>   vfio_multiple_devices_migration_is_supported()
>
> I think it would be clearer in the callers.  This is minor.
>
Yes, of course, I will change that.

Thanks!

>
>>   {
>>       VFIOGroup *group;
>>       VFIODevice *vbasedev;
>>       unsigned int device_num = 0;
>> +    bool all_support_p2p = true;
>>
>>       QLIST_FOREACH(group, &vfio_group_list, next) {
>>           QLIST_FOREACH(vbasedev, &group->device_list, next) {
>>               if (vbasedev->migration) {
>>                   device_num++;
>> +
>> +                if (!(vbasedev->migration->mig_flags & 
>> VFIO_MIGRATION_P2P)) {
>> +                    all_support_p2p = false;
>> +                }
>>               }
>>           }
>>       }
>>
>> -    return device_num;
>> +    return !all_support_p2p && device_num > 1;
>>   }
>>
>>   int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, 
>> Error **errp)
>> @@ -385,19 +395,19 @@ int 
>> vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error 
>> **errp)
>>       int ret;
>>
>>       if (multiple_devices_migration_blocker ||
>> -        vfio_migratable_device_num() <= 1) {
>> +        !vfio_should_block_multiple_devices_migration()) {
>>           return 0;
>>       }
>>
>>       if (vbasedev->enable_migration == ON_OFF_AUTO_ON) {
>> -        error_setg(errp, "Migration is currently not supported with 
>> multiple "
>> -                         "VFIO devices");
>> +        error_setg(errp, "Multiple VFIO devices migration is 
>> supported only if "
>> +                         "all of them support P2P migration");
>>           return -EINVAL;
>>       }
>>
>>       error_setg(&multiple_devices_migration_blocker,
>> -               "Migration is currently not supported with multiple "
>> -               "VFIO devices");
>> +               "Multiple VFIO devices migration is supported only if 
>> all of "
>> +               "them support P2P migration");
>>       ret = migrate_add_blocker(multiple_devices_migration_blocker, 
>> errp);
>>       if (ret < 0) {
>>           error_free(multiple_devices_migration_blocker);
>> @@ -410,7 +420,7 @@ int 
>> vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error 
>> **errp)
>>   void vfio_unblock_multiple_devices_migration(void)
>>   {
>>       if (!multiple_devices_migration_blocker ||
>> -        vfio_migratable_device_num() > 1) {
>> +        vfio_should_block_multiple_devices_migration()) {
>>           return;
>>       }
>>
>
diff mbox series

Patch

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 7c3d636025..753b320739 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -363,21 +363,31 @@  bool vfio_mig_active(void)
 
 static Error *multiple_devices_migration_blocker;
 
-static unsigned int vfio_migratable_device_num(void)
+/*
+ * Multiple devices migration is allowed only if all devices support P2P
+ * migration. Single device migration is allowed regardless of P2P migration
+ * support.
+ */
+static bool vfio_should_block_multiple_devices_migration(void)
 {
     VFIOGroup *group;
     VFIODevice *vbasedev;
     unsigned int device_num = 0;
+    bool all_support_p2p = true;
 
     QLIST_FOREACH(group, &vfio_group_list, next) {
         QLIST_FOREACH(vbasedev, &group->device_list, next) {
             if (vbasedev->migration) {
                 device_num++;
+
+                if (!(vbasedev->migration->mig_flags & VFIO_MIGRATION_P2P)) {
+                    all_support_p2p = false;
+                }
             }
         }
     }
 
-    return device_num;
+    return !all_support_p2p && device_num > 1;
 }
 
 int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error **errp)
@@ -385,19 +395,19 @@  int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error **errp)
     int ret;
 
     if (multiple_devices_migration_blocker ||
-        vfio_migratable_device_num() <= 1) {
+        !vfio_should_block_multiple_devices_migration()) {
         return 0;
     }
 
     if (vbasedev->enable_migration == ON_OFF_AUTO_ON) {
-        error_setg(errp, "Migration is currently not supported with multiple "
-                         "VFIO devices");
+        error_setg(errp, "Multiple VFIO devices migration is supported only if "
+                         "all of them support P2P migration");
         return -EINVAL;
     }
 
     error_setg(&multiple_devices_migration_blocker,
-               "Migration is currently not supported with multiple "
-               "VFIO devices");
+               "Multiple VFIO devices migration is supported only if all of "
+               "them support P2P migration");
     ret = migrate_add_blocker(multiple_devices_migration_blocker, errp);
     if (ret < 0) {
         error_free(multiple_devices_migration_blocker);
@@ -410,7 +420,7 @@  int vfio_block_multiple_devices_migration(VFIODevice *vbasedev, Error **errp)
 void vfio_unblock_multiple_devices_migration(void)
 {
     if (!multiple_devices_migration_blocker ||
-        vfio_migratable_device_num() > 1) {
+        vfio_should_block_multiple_devices_migration()) {
         return;
     }