Si-Wei Liu
2023-Aug-09 12:54 UTC
[PATCH RFC 2/3] vhost-vdpa: introduce descriptor group backend feature
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 at oracle.com>
---
drivers/vhost/vdpa.c | 17 +++++++++++++++++
include/uapi/linux/vhost_types.h | 5 +++++
2 files changed, 22 insertions(+)
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index b43e868..f2e5dce 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -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;
@@ -679,6 +687,7 @@ 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)))
return -EOPNOTSUPP;
@@ -688,6 +697,12 @@ 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;
}
@@ -741,6 +756,8 @@ 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);
if (copy_to_user(featurep, &features, sizeof(features)))
r = -EFAULT;
break;
diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h
index d3aad12a..0856f84 100644
--- a/include/uapi/linux/vhost_types.h
+++ b/include/uapi/linux/vhost_types.h
@@ -181,5 +181,10 @@ struct vhost_vdpa_iova_range {
#define VHOST_BACKEND_F_SUSPEND 0x4
/* Device can be resumed */
#define VHOST_BACKEND_F_RESUME 0x5
+/* Device may expose the descriptor table, avail and used ring in a
+ * different group for ASID binding than the buffers it contains.
+ * Requires VHOST_BACKEND_F_IOTLB_ASID.
+ */
+#define VHOST_BACKEND_F_DESC_ASID 0x6
#endif
--
1.8.3.1
Jason Wang
2023-Aug-10 03:49 UTC
[PATCH RFC 2/3] vhost-vdpa: introduce descriptor group backend feature
On Wed, Aug 9, 2023 at 8:56?PM Si-Wei Liu <si-wei.liu at oracle.com> wrote:> > 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 at oracle.com> > --- > drivers/vhost/vdpa.c | 17 +++++++++++++++++ > include/uapi/linux/vhost_types.h | 5 +++++ > 2 files changed, 22 insertions(+) > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > index b43e868..f2e5dce 100644 > --- a/drivers/vhost/vdpa.c > +++ b/drivers/vhost/vdpa.c > @@ -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; > @@ -679,6 +687,7 @@ 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))) > return -EOPNOTSUPP; > @@ -688,6 +697,12 @@ 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; > } > @@ -741,6 +756,8 @@ 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); > if (copy_to_user(featurep, &features, sizeof(features))) > r = -EFAULT; > break; > diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h > index d3aad12a..0856f84 100644 > --- a/include/uapi/linux/vhost_types.h > +++ b/include/uapi/linux/vhost_types.h > @@ -181,5 +181,10 @@ struct vhost_vdpa_iova_range { > #define VHOST_BACKEND_F_SUSPEND 0x4 > /* Device can be resumed */ > #define VHOST_BACKEND_F_RESUME 0x5 > +/* Device may expose the descriptor table, avail and used ring in a > + * different group for ASID binding than the buffers it contains.Nit: s/a different group/different groups/? Btw, not a native speaker but I think "descriptor" might be confusing since as you explained above, it contains more than just a descriptor table. Thanks> + * Requires VHOST_BACKEND_F_IOTLB_ASID. > + */ > +#define VHOST_BACKEND_F_DESC_ASID 0x6 > > #endif > -- > 1.8.3.1 >