On Wed, Sep 24, 2025 at 1:26 AM Eugenio Perez Martin <[email protected]> wrote: > > On Mon, Sep 22, 2025 at 3:50 AM Jason Wang <[email protected]> wrote: > > > > On Fri, Sep 19, 2025 at 5:34 PM Eugenio Pérez <[email protected]> wrote: > > > > > > Add support for assigning Address Space Identifiers (ASIDs) to each VQ > > > group. This enables mapping each group into a distinct memory space. > > > > > > Now that the driver can change ASID in the middle of operation, the > > > domain that each vq address point is also protected by domain_lock. > > > > > > Signed-off-by: Eugenio Pérez <[email protected]> > > > --- > > > v3: > > > * Get the vduse domain through the vduse_as in the map functions > > > (Jason). > > > * Squash with the patch creating the vduse_as struct (Jason). > > > * Create VDUSE_DEV_MAX_AS instead of comparing agains a magic number > > > (Jason) > > > > > > v2: > > > * Convert the use of mutex to rwlock. > > > > > > RFC v3: > > > * Increase VDUSE_MAX_VQ_GROUPS to 0xffff (Jason). It was set to a lower > > > value to reduce memory consumption, but vqs are already limited to > > > that value and userspace VDUSE is able to allocate that many vqs. > > > * Remove TODO about merging VDUSE_IOTLB_GET_FD ioctl with > > > VDUSE_IOTLB_GET_INFO. > > > * Use of array_index_nospec in VDUSE device ioctls. > > > * Embed vduse_iotlb_entry into vduse_iotlb_entry_v2. > > > * Move the umem mutex to asid struct so there is no contention between > > > ASIDs. > > > > > > RFC v2: > > > * Make iotlb entry the last one of vduse_iotlb_entry_v2 so the first > > > part of the struct is the same. > > > --- > > > drivers/vdpa/vdpa_user/vduse_dev.c | 327 ++++++++++++++++++++--------- > > > include/uapi/linux/vduse.h | 51 ++++- > > > 2 files changed, 281 insertions(+), 97 deletions(-) > > > > > > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c > > > b/drivers/vdpa/vdpa_user/vduse_dev.c > > > index 6fdabc3c910e..c6c70cfd4887 100644 > > > --- a/drivers/vdpa/vdpa_user/vduse_dev.c > > > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c > > > @@ -42,6 +42,7 @@ > > > > > > #define VDUSE_DEV_MAX (1U << MINORBITS) > > > #define VDUSE_DEV_MAX_GROUPS 0xffff > > > +#define VDUSE_DEV_MAX_AS 0xffff > > > #define VDUSE_MAX_BOUNCE_SIZE (1024 * 1024 * 1024) > > > #define VDUSE_MIN_BOUNCE_SIZE (1024 * 1024) > > > #define VDUSE_BOUNCE_SIZE (64 * 1024 * 1024) > > > @@ -89,7 +90,14 @@ struct vduse_umem { > > > struct mm_struct *mm; > > > }; > > > > > > +struct vduse_as { > > > + struct vduse_iova_domain *domain; > > > + struct vduse_umem *umem; > > > + struct mutex mem_lock; > > > +}; > > > + > > > struct vduse_vq_group { > > > + struct vduse_as *as; > > > struct vduse_dev *dev; > > > }; > > > > > > @@ -97,7 +105,7 @@ struct vduse_dev { > > > struct vduse_vdpa *vdev; > > > struct device *dev; > > > struct vduse_virtqueue **vqs; > > > - struct vduse_iova_domain *domain; > > > + struct vduse_as *as; > > > char *name; > > > struct mutex lock; > > > spinlock_t msg_lock; > > > @@ -125,9 +133,8 @@ struct vduse_dev { > > > u32 vq_num; > > > u32 vq_align; > > > u32 ngroups; > > > - struct vduse_umem *umem; > > > + u32 nas; > > > struct vduse_vq_group *groups; > > > - struct mutex mem_lock; > > > unsigned int bounce_size; > > > rwlock_t domain_lock; > > > }; > > > @@ -324,7 +331,7 @@ static int vduse_dev_set_status(struct vduse_dev > > > *dev, u8 status) > > > return vduse_dev_msg_sync(dev, &msg); > > > } > > > > > > -static int vduse_dev_update_iotlb(struct vduse_dev *dev, > > > +static int vduse_dev_update_iotlb(struct vduse_dev *dev, u32 asid, > > > u64 start, u64 last) > > > { > > > struct vduse_dev_msg msg = { 0 }; > > > @@ -333,8 +340,14 @@ static int vduse_dev_update_iotlb(struct vduse_dev > > > *dev, > > > return -EINVAL; > > > > > > msg.req.type = VDUSE_UPDATE_IOTLB; > > > - msg.req.iova.start = start; > > > - msg.req.iova.last = last; > > > + if (dev->api_version < VDUSE_API_VERSION_1) { > > > + msg.req.iova.start = start; > > > + msg.req.iova.last = last; > > > + } else { > > > + msg.req.iova_v2.start = start; > > > + msg.req.iova_v2.last = last; > > > + msg.req.iova_v2.asid = asid; > > > + } > > > > > > return vduse_dev_msg_sync(dev, &msg); > > > } > > > @@ -446,14 +459,29 @@ static __poll_t vduse_dev_poll(struct file *file, > > > poll_table *wait) > > > return mask; > > > } > > > > > > +/* Force set the asid to a vq group without a message to the VDUSE > > > device */ > > > +static void vduse_set_group_asid_nomsg(struct vduse_dev *dev, > > > + unsigned int group, unsigned int > > > asid) > > > +{ > > > + write_lock(&dev->domain_lock); > > > + dev->groups[group].as = &dev->as[asid]; > > > + write_unlock(&dev->domain_lock); > > > +} > > > + > > > static void vduse_dev_reset(struct vduse_dev *dev) > > > { > > > int i; > > > - struct vduse_iova_domain *domain = dev->domain; > > > > > > /* The coherent mappings are handled in vduse_dev_free_coherent() > > > */ > > > - if (domain && domain->bounce_map) > > > - vduse_domain_reset_bounce_map(domain); > > > + for (i = 0; i < dev->nas; i++) { > > > + struct vduse_iova_domain *domain = dev->as[i].domain; > > > + > > > + if (domain && domain->bounce_map) > > > + vduse_domain_reset_bounce_map(domain); > > > + } > > > + > > > + for (i = 0; i < dev->ngroups; i++) > > > + vduse_set_group_asid_nomsg(dev, i, 0); > > > > > > down_write(&dev->rwsem); > > > > > > @@ -639,6 +667,29 @@ static union virtio_map vduse_get_vq_map(struct > > > vdpa_device *vdpa, u16 idx) > > > return ret; > > > } > > > > > > +static int vduse_set_group_asid(struct vdpa_device *vdpa, unsigned int > > > group, > > > + unsigned int asid) > > > +{ > > > + struct vduse_dev *dev = vdpa_to_vduse(vdpa); > > > + struct vduse_dev_msg msg = { 0 }; > > > + int r; > > > + > > > + if (dev->api_version < VDUSE_API_VERSION_1 || > > > + group >= dev->ngroups || asid >= dev->nas) > > > + return -EINVAL; > > > + > > > + msg.req.type = VDUSE_SET_VQ_GROUP_ASID; > > > + msg.req.vq_group_asid.group = group; > > > + msg.req.vq_group_asid.asid = asid; > > > + > > > + r = vduse_dev_msg_sync(dev, &msg); > > > + if (r < 0) > > > + return r; > > > + > > > + vduse_set_group_asid_nomsg(dev, group, asid); > > > + return 0; > > > +} > > > + > > > static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx, > > > struct vdpa_vq_state *state) > > > { > > > @@ -810,13 +861,13 @@ static int vduse_vdpa_set_map(struct vdpa_device > > > *vdpa, > > > struct vduse_dev *dev = vdpa_to_vduse(vdpa); > > > int ret; > > > > > > - ret = vduse_domain_set_map(dev->domain, iotlb); > > > + ret = vduse_domain_set_map(dev->as[asid].domain, iotlb); > > > if (ret) > > > return ret; > > > > > > - ret = vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX); > > > + ret = vduse_dev_update_iotlb(dev, asid, 0ULL, ULLONG_MAX); > > > if (ret) { > > > - vduse_domain_clear_map(dev->domain, iotlb); > > > + vduse_domain_clear_map(dev->as[asid].domain, iotlb); > > > return ret; > > > } > > > > > > @@ -859,6 +910,7 @@ static const struct vdpa_config_ops > > > vduse_vdpa_config_ops = { > > > .get_vq_affinity = vduse_vdpa_get_vq_affinity, > > > .reset = vduse_vdpa_reset, > > > .set_map = vduse_vdpa_set_map, > > > + .set_group_asid = vduse_set_group_asid, > > > .get_vq_map = vduse_get_vq_map, > > > .free = vduse_vdpa_free, > > > }; > > > @@ -874,9 +926,10 @@ static void vduse_dev_sync_single_for_device(union > > > virtio_map token, > > > return; > > > > > > vdev = token.group->dev; > > > - domain = vdev->domain; > > > - > > > + read_lock(&vdev->domain_lock); > > > > This introduce atomic operation in the datapath, I wonder if we can > > switch to use RCU instead. > > > > I think it is a path that is worth exploring. The reason I chose > rwlock (and just plain mutex before) is that > vduse_domain_sync_single_for_device and > vduse_domain_sync_single_for_cpu already take a read lock, so it seems > the overhead was ok. > > Can we do it on top of this series? I think both using RCU can improve > the performance for sure, but just taking out one of them would not > buy us a lot.
That's fine. Thanks
