* [PATCH] vhost-vdpa: Expose ASID group change after DRIVER_OK via backend feature
@ 2026-05-11 9:45 Dragos Tatulea
2026-05-21 7:14 ` Dragos Tatulea
2026-05-21 8:26 ` Eugenio Perez Martin
0 siblings, 2 replies; 5+ messages in thread
From: Dragos Tatulea @ 2026-05-11 9:45 UTC (permalink / raw)
To: virtualization, Dragos Tatulea, Michael S. Tsirkin, Jason Wang,
Xuan Zhuo, Eugenio Pérez
Cc: Tariq Toukan, Shahar Shitrit, linux-kernel, kvm, netdev
The commit in the fixes tag blocked VHOST_VDPA_SET_GROUP_ASID operations
once DRIVER_OK is set. That is too strict for devices which can safely
handle this during live migration flows.
Bring back this behavior under a new vhost backend feature flag. The
feature is supported by mlx5 and vdpa_sim devices.
Fixes: 3543b04a4ea3 ("vhost: forbid change vq groups ASID if DRIVER_OK is set")
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Shahar Shitrit <shshitrit@nvidia.com>
---
drivers/vdpa/mlx5/net/mlx5_vnet.c | 3 ++-
drivers/vdpa/vdpa_sim/vdpa_sim.c | 3 ++-
drivers/vhost/vdpa.c | 13 +++++++++++--
include/uapi/linux/vhost_types.h | 4 ++++
4 files changed, 19 insertions(+), 4 deletions(-)
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index ad0d5fbbbca8..f89177957c76 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2906,7 +2906,8 @@ static void unregister_link_notifier(struct mlx5_vdpa_net *ndev)
static u64 mlx5_vdpa_get_backend_features(const struct vdpa_device *vdpa)
{
- return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK);
+ return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
+ BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK);
}
static int mlx5_vdpa_set_driver_features(struct vdpa_device *vdev, u64 features)
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 8cb1cc2ea139..253c7fb35ea0 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -428,7 +428,8 @@ static u64 vdpasim_get_device_features(struct vdpa_device *vdpa)
static u64 vdpasim_get_backend_features(const struct vdpa_device *vdpa)
{
- return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK);
+ return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
+ BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK);
}
static int vdpasim_set_driver_features(struct vdpa_device *vdpa, u64 features)
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 692564b1bcbb..67b3f49fa709 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -682,7 +682,8 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
return -EFAULT;
if (idx >= vdpa->ngroups || s.num >= vdpa->nas)
return -EINVAL;
- if (ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK)
+ if ((ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK) &&
+ !vhost_backend_has_feature(vq, VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK))
return -EBUSY;
if (!ops->set_group_asid)
return -EOPNOTSUPP;
@@ -791,7 +792,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
BIT_ULL(VHOST_BACKEND_F_IOTLB_PERSIST) |
BIT_ULL(VHOST_BACKEND_F_SUSPEND) |
BIT_ULL(VHOST_BACKEND_F_RESUME) |
- BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK)))
+ BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
+ BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)))
return -EOPNOTSUPP;
if ((features & BIT_ULL(VHOST_BACKEND_F_SUSPEND)) &&
!vhost_vdpa_can_suspend(v))
@@ -805,6 +807,13 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
if ((features & BIT_ULL(VHOST_BACKEND_F_DESC_ASID)) &&
!vhost_vdpa_has_desc_group(v))
return -EOPNOTSUPP;
+ if (features & BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)) {
+ if (!(features & BIT_ULL(VHOST_BACKEND_F_IOTLB_ASID)))
+ return -EINVAL;
+ if (!(vhost_vdpa_get_backend_features(v) &
+ BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)))
+ return -EOPNOTSUPP;
+ }
if ((features & BIT_ULL(VHOST_BACKEND_F_IOTLB_PERSIST)) &&
!vhost_vdpa_has_persistent_map(v))
return -EOPNOTSUPP;
diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h
index 1c39cc5f5a31..ec1ff8a2e260 100644
--- a/include/uapi/linux/vhost_types.h
+++ b/include/uapi/linux/vhost_types.h
@@ -197,5 +197,9 @@ struct vhost_vdpa_iova_range {
#define VHOST_BACKEND_F_DESC_ASID 0x7
/* IOTLB don't flush memory mapping across device reset */
#define VHOST_BACKEND_F_IOTLB_PERSIST 0x8
+/* Device supports changing the group ASID after DRIVER_OK.
+ * Requires VHOST_BACKEND_F_IOTLB_ASID.
+ */
+#define VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK 0x9
#endif
--
2.54.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] vhost-vdpa: Expose ASID group change after DRIVER_OK via backend feature
2026-05-11 9:45 [PATCH] vhost-vdpa: Expose ASID group change after DRIVER_OK via backend feature Dragos Tatulea
@ 2026-05-21 7:14 ` Dragos Tatulea
2026-05-21 8:26 ` Eugenio Perez Martin
1 sibling, 0 replies; 5+ messages in thread
From: Dragos Tatulea @ 2026-05-21 7:14 UTC (permalink / raw)
To: virtualization, Michael S. Tsirkin, Jason Wang, Xuan Zhuo,
Eugenio Pérez
Cc: Tariq Toukan, Shahar Shitrit, linux-kernel, kvm, netdev
On Mon, May 11, 2026 at 12:45:03PM +0300, Dragos Tatulea wrote:
> The commit in the fixes tag blocked VHOST_VDPA_SET_GROUP_ASID operations
> once DRIVER_OK is set. That is too strict for devices which can safely
> handle this during live migration flows.
>
> Bring back this behavior under a new vhost backend feature flag. The
> feature is supported by mlx5 and vdpa_sim devices.
>
> Fixes: 3543b04a4ea3 ("vhost: forbid change vq groups ASID if DRIVER_OK is set")
> Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
> Reviewed-by: Shahar Shitrit <shshitrit@nvidia.com>
> ---
Gentle ping.
Thanks,
Dragos
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] vhost-vdpa: Expose ASID group change after DRIVER_OK via backend feature
2026-05-11 9:45 [PATCH] vhost-vdpa: Expose ASID group change after DRIVER_OK via backend feature Dragos Tatulea
2026-05-21 7:14 ` Dragos Tatulea
@ 2026-05-21 8:26 ` Eugenio Perez Martin
2026-06-29 9:39 ` Dragos Tatulea
1 sibling, 1 reply; 5+ messages in thread
From: Eugenio Perez Martin @ 2026-05-21 8:26 UTC (permalink / raw)
To: Dragos Tatulea
Cc: virtualization, Michael S. Tsirkin, Jason Wang, Xuan Zhuo,
Tariq Toukan, Shahar Shitrit, linux-kernel, kvm, netdev
On Mon, May 11, 2026 at 11:46 AM Dragos Tatulea <dtatulea@nvidia.com> wrote:
>
> The commit in the fixes tag blocked VHOST_VDPA_SET_GROUP_ASID operations
> once DRIVER_OK is set. That is too strict for devices which can safely
> handle this during live migration flows.
>
> Bring back this behavior under a new vhost backend feature flag. The
> feature is supported by mlx5 and vdpa_sim devices.
>
> Fixes: 3543b04a4ea3 ("vhost: forbid change vq groups ASID if DRIVER_OK is set")
> Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
> Reviewed-by: Shahar Shitrit <shshitrit@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
> ---
> drivers/vdpa/mlx5/net/mlx5_vnet.c | 3 ++-
> drivers/vdpa/vdpa_sim/vdpa_sim.c | 3 ++-
> drivers/vhost/vdpa.c | 13 +++++++++++--
> include/uapi/linux/vhost_types.h | 4 ++++
> 4 files changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index ad0d5fbbbca8..f89177957c76 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -2906,7 +2906,8 @@ static void unregister_link_notifier(struct mlx5_vdpa_net *ndev)
>
> static u64 mlx5_vdpa_get_backend_features(const struct vdpa_device *vdpa)
> {
> - return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK);
> + return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
> + BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK);
> }
>
> static int mlx5_vdpa_set_driver_features(struct vdpa_device *vdev, u64 features)
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index 8cb1cc2ea139..253c7fb35ea0 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -428,7 +428,8 @@ static u64 vdpasim_get_device_features(struct vdpa_device *vdpa)
>
> static u64 vdpasim_get_backend_features(const struct vdpa_device *vdpa)
> {
> - return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK);
> + return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
> + BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK);
> }
>
> static int vdpasim_set_driver_features(struct vdpa_device *vdpa, u64 features)
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 692564b1bcbb..67b3f49fa709 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -682,7 +682,8 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
> return -EFAULT;
> if (idx >= vdpa->ngroups || s.num >= vdpa->nas)
> return -EINVAL;
> - if (ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK)
> + if ((ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK) &&
> + !vhost_backend_has_feature(vq, VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK))
> return -EBUSY;
> if (!ops->set_group_asid)
> return -EOPNOTSUPP;
> @@ -791,7 +792,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
> BIT_ULL(VHOST_BACKEND_F_IOTLB_PERSIST) |
> BIT_ULL(VHOST_BACKEND_F_SUSPEND) |
> BIT_ULL(VHOST_BACKEND_F_RESUME) |
> - BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK)))
> + BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
> + BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)))
> return -EOPNOTSUPP;
> if ((features & BIT_ULL(VHOST_BACKEND_F_SUSPEND)) &&
> !vhost_vdpa_can_suspend(v))
> @@ -805,6 +807,13 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
> if ((features & BIT_ULL(VHOST_BACKEND_F_DESC_ASID)) &&
> !vhost_vdpa_has_desc_group(v))
> return -EOPNOTSUPP;
Ouch to me here. By reading the errno manual:
Nit: By reading errno(3):
ENOTSUP - Operation not supported (POSIX.1-2001).
EOPNOTSUPP - Operation not supported on socket (POSIX.1-2001).
I picked the wrong constant even if they share the same errno value
(by the same page of the manual). MST, is it worth changing it?
> + if (features & BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)) {
> + if (!(features & BIT_ULL(VHOST_BACKEND_F_IOTLB_ASID)))
> + return -EINVAL;
> + if (!(vhost_vdpa_get_backend_features(v) &
> + BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)))
> + return -EOPNOTSUPP;
> + }
> if ((features & BIT_ULL(VHOST_BACKEND_F_IOTLB_PERSIST)) &&
> !vhost_vdpa_has_persistent_map(v))
> return -EOPNOTSUPP;
> diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h
> index 1c39cc5f5a31..ec1ff8a2e260 100644
> --- a/include/uapi/linux/vhost_types.h
> +++ b/include/uapi/linux/vhost_types.h
> @@ -197,5 +197,9 @@ struct vhost_vdpa_iova_range {
> #define VHOST_BACKEND_F_DESC_ASID 0x7
> /* IOTLB don't flush memory mapping across device reset */
> #define VHOST_BACKEND_F_IOTLB_PERSIST 0x8
> +/* Device supports changing the group ASID after DRIVER_OK.
> + * Requires VHOST_BACKEND_F_IOTLB_ASID.
> + */
> +#define VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK 0x9
>
> #endif
> --
> 2.54.0
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] vhost-vdpa: Expose ASID group change after DRIVER_OK via backend feature
2026-05-21 8:26 ` Eugenio Perez Martin
@ 2026-06-29 9:39 ` Dragos Tatulea
2026-07-27 14:08 ` Dragos Tatulea
0 siblings, 1 reply; 5+ messages in thread
From: Dragos Tatulea @ 2026-06-29 9:39 UTC (permalink / raw)
To: Eugenio Perez Martin
Cc: virtualization, Michael S. Tsirkin, Jason Wang, Xuan Zhuo,
Tariq Toukan, Shahar Shitrit, linux-kernel, kvm, netdev
On 21.05.26 10:26, Eugenio Perez Martin wrote:
> On Mon, May 11, 2026 at 11:46 AM Dragos Tatulea <dtatulea@nvidia.com> wrote:
>>
>> The commit in the fixes tag blocked VHOST_VDPA_SET_GROUP_ASID operations
>> once DRIVER_OK is set. That is too strict for devices which can safely
>> handle this during live migration flows.
>>
>> Bring back this behavior under a new vhost backend feature flag. The
>> feature is supported by mlx5 and vdpa_sim devices.
>>
>> Fixes: 3543b04a4ea3 ("vhost: forbid change vq groups ASID if DRIVER_OK is set")
>> Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
>> Reviewed-by: Shahar Shitrit <shshitrit@nvidia.com>
>
> Acked-by: Eugenio Pérez <eperezma@redhat.com>
>
>> ---
>> drivers/vdpa/mlx5/net/mlx5_vnet.c | 3 ++-
>> drivers/vdpa/vdpa_sim/vdpa_sim.c | 3 ++-
>> drivers/vhost/vdpa.c | 13 +++++++++++--
>> include/uapi/linux/vhost_types.h | 4 ++++
>> 4 files changed, 19 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> index ad0d5fbbbca8..f89177957c76 100644
>> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> @@ -2906,7 +2906,8 @@ static void unregister_link_notifier(struct mlx5_vdpa_net *ndev)
>>
>> static u64 mlx5_vdpa_get_backend_features(const struct vdpa_device *vdpa)
>> {
>> - return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK);
>> + return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
>> + BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK);
>> }
>>
>> static int mlx5_vdpa_set_driver_features(struct vdpa_device *vdev, u64 features)
>> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> index 8cb1cc2ea139..253c7fb35ea0 100644
>> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> @@ -428,7 +428,8 @@ static u64 vdpasim_get_device_features(struct vdpa_device *vdpa)
>>
>> static u64 vdpasim_get_backend_features(const struct vdpa_device *vdpa)
>> {
>> - return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK);
>> + return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
>> + BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK);
>> }
>>
>> static int vdpasim_set_driver_features(struct vdpa_device *vdpa, u64 features)
>> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>> index 692564b1bcbb..67b3f49fa709 100644
>> --- a/drivers/vhost/vdpa.c
>> +++ b/drivers/vhost/vdpa.c
>> @@ -682,7 +682,8 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
>> return -EFAULT;
>> if (idx >= vdpa->ngroups || s.num >= vdpa->nas)
>> return -EINVAL;
>> - if (ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK)
>> + if ((ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK) &&
>> + !vhost_backend_has_feature(vq, VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK))
>> return -EBUSY;
>> if (!ops->set_group_asid)
>> return -EOPNOTSUPP;
>> @@ -791,7 +792,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
>> BIT_ULL(VHOST_BACKEND_F_IOTLB_PERSIST) |
>> BIT_ULL(VHOST_BACKEND_F_SUSPEND) |
>> BIT_ULL(VHOST_BACKEND_F_RESUME) |
>> - BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK)))
>> + BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
>> + BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)))
>> return -EOPNOTSUPP;
>> if ((features & BIT_ULL(VHOST_BACKEND_F_SUSPEND)) &&
>> !vhost_vdpa_can_suspend(v))
>> @@ -805,6 +807,13 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
>> if ((features & BIT_ULL(VHOST_BACKEND_F_DESC_ASID)) &&
>> !vhost_vdpa_has_desc_group(v))
>> return -EOPNOTSUPP;
>
> Ouch to me here. By reading the errno manual:
>
> Nit: By reading errno(3):
> ENOTSUP - Operation not supported (POSIX.1-2001).
> EOPNOTSUPP - Operation not supported on socket (POSIX.1-2001).
>
> I picked the wrong constant even if they share the same errno value
> (by the same page of the manual). MST, is it worth changing it?
>
>> + if (features & BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)) {
>> + if (!(features & BIT_ULL(VHOST_BACKEND_F_IOTLB_ASID)))
>> + return -EINVAL;
>> + if (!(vhost_vdpa_get_backend_features(v) &
>> + BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)))
>> + return -EOPNOTSUPP;
>> + }
>> if ((features & BIT_ULL(VHOST_BACKEND_F_IOTLB_PERSIST)) &&
>> !vhost_vdpa_has_persistent_map(v))
>> return -EOPNOTSUPP;
>> diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h
>> index 1c39cc5f5a31..ec1ff8a2e260 100644
>> --- a/include/uapi/linux/vhost_types.h
>> +++ b/include/uapi/linux/vhost_types.h
>> @@ -197,5 +197,9 @@ struct vhost_vdpa_iova_range {
>> #define VHOST_BACKEND_F_DESC_ASID 0x7
>> /* IOTLB don't flush memory mapping across device reset */
>> #define VHOST_BACKEND_F_IOTLB_PERSIST 0x8
>> +/* Device supports changing the group ASID after DRIVER_OK.
>> + * Requires VHOST_BACKEND_F_IOTLB_ASID.
>> + */
>> +#define VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK 0x9
>>
>> #endif
>> --
>> 2.54.0
>>
>
Gentle ping. Is this patch missing anything?
Thanks,
Dragos
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] vhost-vdpa: Expose ASID group change after DRIVER_OK via backend feature
2026-06-29 9:39 ` Dragos Tatulea
@ 2026-07-27 14:08 ` Dragos Tatulea
0 siblings, 0 replies; 5+ messages in thread
From: Dragos Tatulea @ 2026-07-27 14:08 UTC (permalink / raw)
To: Eugenio Perez Martin
Cc: virtualization, Michael S. Tsirkin, Jason Wang, Xuan Zhuo,
Tariq Toukan, Shahar Shitrit, linux-kernel, kvm, netdev
On 29.06.26 11:39, Dragos Tatulea wrote:
>
>
> On 21.05.26 10:26, Eugenio Perez Martin wrote:
>> On Mon, May 11, 2026 at 11:46 AM Dragos Tatulea <dtatulea@nvidia.com> wrote:
>>>
>>> The commit in the fixes tag blocked VHOST_VDPA_SET_GROUP_ASID operations
>>> once DRIVER_OK is set. That is too strict for devices which can safely
>>> handle this during live migration flows.
>>>
>>> Bring back this behavior under a new vhost backend feature flag. The
>>> feature is supported by mlx5 and vdpa_sim devices.
>>>
>>> Fixes: 3543b04a4ea3 ("vhost: forbid change vq groups ASID if DRIVER_OK is set")
>>> Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
>>> Reviewed-by: Shahar Shitrit <shshitrit@nvidia.com>
>>
>> Acked-by: Eugenio Pérez <eperezma@redhat.com>
>>
>>> ---
>>> drivers/vdpa/mlx5/net/mlx5_vnet.c | 3 ++-
>>> drivers/vdpa/vdpa_sim/vdpa_sim.c | 3 ++-
>>> drivers/vhost/vdpa.c | 13 +++++++++++--
>>> include/uapi/linux/vhost_types.h | 4 ++++
>>> 4 files changed, 19 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>> index ad0d5fbbbca8..f89177957c76 100644
>>> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>>> @@ -2906,7 +2906,8 @@ static void unregister_link_notifier(struct mlx5_vdpa_net *ndev)
>>>
>>> static u64 mlx5_vdpa_get_backend_features(const struct vdpa_device *vdpa)
>>> {
>>> - return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK);
>>> + return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
>>> + BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK);
>>> }
>>>
>>> static int mlx5_vdpa_set_driver_features(struct vdpa_device *vdev, u64 features)
>>> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>>> index 8cb1cc2ea139..253c7fb35ea0 100644
>>> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
>>> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>>> @@ -428,7 +428,8 @@ static u64 vdpasim_get_device_features(struct vdpa_device *vdpa)
>>>
>>> static u64 vdpasim_get_backend_features(const struct vdpa_device *vdpa)
>>> {
>>> - return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK);
>>> + return BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
>>> + BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK);
>>> }
>>>
>>> static int vdpasim_set_driver_features(struct vdpa_device *vdpa, u64 features)
>>> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>>> index 692564b1bcbb..67b3f49fa709 100644
>>> --- a/drivers/vhost/vdpa.c
>>> +++ b/drivers/vhost/vdpa.c
>>> @@ -682,7 +682,8 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
>>> return -EFAULT;
>>> if (idx >= vdpa->ngroups || s.num >= vdpa->nas)
>>> return -EINVAL;
>>> - if (ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK)
>>> + if ((ops->get_status(vdpa) & VIRTIO_CONFIG_S_DRIVER_OK) &&
>>> + !vhost_backend_has_feature(vq, VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK))
>>> return -EBUSY;
>>> if (!ops->set_group_asid)
>>> return -EOPNOTSUPP;
>>> @@ -791,7 +792,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
>>> BIT_ULL(VHOST_BACKEND_F_IOTLB_PERSIST) |
>>> BIT_ULL(VHOST_BACKEND_F_SUSPEND) |
>>> BIT_ULL(VHOST_BACKEND_F_RESUME) |
>>> - BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK)))
>>> + BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK) |
>>> + BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)))
>>> return -EOPNOTSUPP;
>>> if ((features & BIT_ULL(VHOST_BACKEND_F_SUSPEND)) &&
>>> !vhost_vdpa_can_suspend(v))
>>> @@ -805,6 +807,13 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
>>> if ((features & BIT_ULL(VHOST_BACKEND_F_DESC_ASID)) &&
>>> !vhost_vdpa_has_desc_group(v))
>>> return -EOPNOTSUPP;
>>
>> Ouch to me here. By reading the errno manual:
>>
>> Nit: By reading errno(3):
>> ENOTSUP - Operation not supported (POSIX.1-2001).
>> EOPNOTSUPP - Operation not supported on socket (POSIX.1-2001).
>>
>> I picked the wrong constant even if they share the same errno value
>> (by the same page of the manual). MST, is it worth changing it?
>>
>>> + if (features & BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)) {
>>> + if (!(features & BIT_ULL(VHOST_BACKEND_F_IOTLB_ASID)))
>>> + return -EINVAL;
>>> + if (!(vhost_vdpa_get_backend_features(v) &
>>> + BIT_ULL(VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK)))
>>> + return -EOPNOTSUPP;
>>> + }
>>> if ((features & BIT_ULL(VHOST_BACKEND_F_IOTLB_PERSIST)) &&
>>> !vhost_vdpa_has_persistent_map(v))
>>> return -EOPNOTSUPP;
>>> diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h
>>> index 1c39cc5f5a31..ec1ff8a2e260 100644
>>> --- a/include/uapi/linux/vhost_types.h
>>> +++ b/include/uapi/linux/vhost_types.h
>>> @@ -197,5 +197,9 @@ struct vhost_vdpa_iova_range {
>>> #define VHOST_BACKEND_F_DESC_ASID 0x7
>>> /* IOTLB don't flush memory mapping across device reset */
>>> #define VHOST_BACKEND_F_IOTLB_PERSIST 0x8
>>> +/* Device supports changing the group ASID after DRIVER_OK.
>>> + * Requires VHOST_BACKEND_F_IOTLB_ASID.
>>> + */
>>> +#define VHOST_BACKEND_F_GROUP_ASID_AFTER_DRIVER_OK 0x9
>>>
>>> #endif
>>> --
>>> 2.54.0
>>>
>>
>
> Gentle ping. Is this patch missing anything?
>
One more ping.
Thanks,
Dragos
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2026-07-27 14:08 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-05-11 9:45 [PATCH] vhost-vdpa: Expose ASID group change after DRIVER_OK via backend feature Dragos Tatulea
2026-05-21 7:14 ` Dragos Tatulea
2026-05-21 8:26 ` Eugenio Perez Martin
2026-06-29 9:39 ` Dragos Tatulea
2026-07-27 14:08 ` Dragos Tatulea
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