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vhost-vdpa: introduce descriptor group backend feature

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Userspace knows if the device has dedicated descriptor group or not
by checking this feature bit.

It's only exposed if the vdpa driver backend implements the
.get_vq_desc_group() operation callback. Userspace trying to negotiate
this feature when it or the dependent _F_IOTLB_ASID feature hasn't
been exposed will result in an error.

Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20231018171456.1624030-5-dtatulea@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Tested-by: Si-Wei Liu <si-wei.liu@oracle.com>
Tested-by: Lei Yang <leiyang@redhat.com>
This commit is contained in:
Si-Wei Liu 2023-10-18 20:14:42 +03:00 committed by Michael S. Tsirkin
parent a72cac6067
commit 7db0d6027e
2 changed files with 22 additions and 0 deletions
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17
drivers/vhost/vdpa.c
View File

@ -389,6 +389,14 @@ static bool vhost_vdpa_can_resume(const struct vhost_vdpa *v)
return ops->resume;
}
static bool vhost_vdpa_has_desc_group(const struct vhost_vdpa *v)
{
struct vdpa_device *vdpa = v->vdpa;
const struct vdpa_config_ops *ops = vdpa->config;
return ops->get_vq_desc_group;
}
static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep)
{
struct vdpa_device *vdpa = v->vdpa;
@ -690,6 +698,7 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
if (copy_from_user(&features, featurep, sizeof(features)))
return -EFAULT;
if (features & ~(VHOST_VDPA_BACKEND_FEATURES |
BIT_ULL(VHOST_BACKEND_F_DESC_ASID) |
BIT_ULL(VHOST_BACKEND_F_SUSPEND) |
BIT_ULL(VHOST_BACKEND_F_RESUME) |
BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK)))
@ -700,6 +709,12 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
if ((features & BIT_ULL(VHOST_BACKEND_F_RESUME)) &&
!vhost_vdpa_can_resume(v))
return -EOPNOTSUPP;
if ((features & BIT_ULL(VHOST_BACKEND_F_DESC_ASID)) &&
!(features & BIT_ULL(VHOST_BACKEND_F_IOTLB_ASID)))
return -EINVAL;
if ((features & BIT_ULL(VHOST_BACKEND_F_DESC_ASID)) &&
!vhost_vdpa_has_desc_group(v))
return -EOPNOTSUPP;
vhost_set_backend_features(&v->vdev, features);
return 0;
}
@ -753,6 +768,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
features |= BIT_ULL(VHOST_BACKEND_F_SUSPEND);
if (vhost_vdpa_can_resume(v))
features |= BIT_ULL(VHOST_BACKEND_F_RESUME);
if (vhost_vdpa_has_desc_group(v))
features |= BIT_ULL(VHOST_BACKEND_F_DESC_ASID);
features |= vhost_vdpa_get_backend_features(v);
if (copy_to_user(featurep, &features, sizeof(features)))
r = -EFAULT;

5
include/uapi/linux/vhost_types.h
View File

@ -185,5 +185,10 @@ struct vhost_vdpa_iova_range {
* DRIVER_OK
*/
#define VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK 0x6
/* Device may expose the virtqueue's descriptor area, driver area and
* device area to a different group for ASID binding than where its
* buffers may reside. Requires VHOST_BACKEND_F_IOTLB_ASID.
*/
#define VHOST_BACKEND_F_DESC_ASID 0x7
#endif