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vhost-vdpa: introduce descriptor group backend feature

Browse source 
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