On Sun, Jan 11, 2026 at 1:03 AM Michael S. Tsirkin <[email protected]> wrote:
>
> On Fri, Jan 09, 2026 at 04:24:29PM +0100, Eugenio Pérez wrote:
> > Add support for assigning Address Space Identifiers (ASIDs) to each VQ
> > group.  This enables mapping each group into a distinct memory space.
> >
> > The vq group to ASID association is protected by a rwlock now.  But the
> > mutex domain_lock keeps protecting the domains of all ASIDs, as some
> > operations like the one related with the bounce buffer size still
> > requires to lock all the ASIDs.
> >
> > Signed-off-by: Eugenio Pérez <[email protected]>
> >
> > ---
> > Future improvements can include performance optimizations on top like
> > ore to RCU or thread synchronized atomics, or hardening by tracking ASID
> > or ASID hashes on unused bits of the DMA address.
> >
> > Tested virtio_vdpa by adding manually two threads in vduse_set_status:
> > one of them modifies the vq group 0 ASID and the other one map and unmap
> > memory continuously.  After a while, the two threads stop and the usual
> > work continues.  Test with version 0, version 1 with the old ioctl, and
> > verion 1 with the new ioctl.
> >
> > Tested with vhost_vdpa by migrating a VM while ping on OVS+VDUSE.  A few
> > workaround were needed in some parts:
> > * Do not enable CVQ before data vqs in QEMU, as VDUSE does not forward
> >   the enable message to the userland device.  This will be solved in the
> >   future.
> > * Share the suspended state between all vhost devices in QEMU:
> >   https://lists.nongnu.org/archive/html/qemu-devel/2025-11/msg02947.html
> > * Implement a fake VDUSE suspend vdpa operation callback that always
> >   returns true in the kernel.  DPDK suspend the device at the first
> >   GET_VRING_BASE.
> > * Remove the CVQ blocker in ASID.
> >
> > The driver vhost_vdpa was also tested with version 0, version 1 with the
> > old ioctl, version 1 with the new ioctl but only one ASID, and version 1
> > with many ASID.
> >
> > ---
> > v11:
> > * Remove duplicated free_pages_exact in vduse_domain_free_coherent
> >   (Jason).
> > * Do not take the vq groups lock if nas == 1.
> > * Do not reset the vq group ASID in vq reset (Jason).  Removed extra
> >   function vduse_set_group_asid_nomsg, not needed anymore.
> > * Move the vduse_iotlb_entry_v2 argument to a new ioctl, as argument
> >   didn't match the previous VDUSE_IOTLB_GET_FD.
> > * Move the asid < dev->nas check to vdpa core.
> >
> > v10:
> > * Back to rwlock version so stronger locks are used.
> > * Take out allocations from rwlock.
> > * Forbid changing ASID of a vq group after DRIVER_OK (Jason)
> > * Remove bad fetching again of domain variable in
> >   vduse_dev_max_mapping_size (Yongji).
> > * Remove unused vdev definition in vdpa map_ops callbacks (kernel test
> >   robot).
> >
> > v9:
> > * Replace mutex with rwlock, as the vdpa map_ops can run from atomic
> >   context.
> >
> > v8:
> > * Revert the mutex to rwlock change, it needs proper profiling to
> >   justify it.
> >
> > v7:
> > * Take write lock in the error path (Jason).
> >
> > v6:
> > * Make vdpa_dev_add use gotos for error handling (MST).
> > * s/(dev->api_version < 1) ?/(dev->api_version < VDUSE_API_VERSION_1) ?/
> >   (MST).
> > * Fix struct name not matching in the doc.
> >
> > v5:
> > * Properly return errno if copy_to_user returns >0 in VDUSE_IOTLB_GET_FD
> >   ioctl (Jason).
> > * Properly set domain bounce size to divide equally between nas (Jason).
> > * Exclude "padding" member from the only >V1 members in
> >   vduse_dev_request.
> >
> > v4:
> > * Divide each domain bounce size between the device bounce size (Jason).
> > * revert unneeded addr = NULL assignment (Jason)
> > * Change if (x && (y || z)) return to if (x) { if (y) return; if (z)
> >   return; } (Jason)
> > * Change a bad multiline comment, using @ caracter instead of * (Jason).
> > * Consider config->nas == 0 as a fail (Jason).
> >
> > 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 | 392 ++++++++++++++++++++---------
> >  include/uapi/linux/vduse.h         |  63 ++++-
> >  2 files changed, 333 insertions(+), 122 deletions(-)
> >
> > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c 
> > b/drivers/vdpa/vdpa_user/vduse_dev.c
> > index bf437816fd7d..8227b5e9f3f6 100644
> > --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> > @@ -41,6 +41,7 @@
> >
> >  #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)
> > @@ -86,7 +87,15 @@ 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 {
> > +     rwlock_t as_lock;
> > +     struct vduse_as *as; /* Protected by as_lock */
> >       struct vduse_dev *dev;
> >  };
> >
> > @@ -94,7 +103,7 @@ 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;
> > @@ -122,9 +131,8 @@ 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;
> >       struct mutex domain_lock;
> >  };
> > @@ -314,7 +322,7 @@ 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 };
> > @@ -323,8 +331,14 @@ 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);
> >  }
> > @@ -439,11 +453,14 @@ static __poll_t vduse_dev_poll(struct file *file, 
> > poll_table *wait)
> >  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;
>
> I do not understand the locking here an in many other places.
> dev->as is dereferenced here apparently outside as_lock?
>

The virtqueue groups' "as_lock" member protects the virtqueue groups'
"as" pointer. But we're not accessing any vq groups "as" member here,
we're accessing the dev->as[i].domain pointer here, which doesn't
change in all the lifetime of the device.

>
>
> > +
> > +             if (domain && domain->bounce_map)
> > +                     vduse_domain_reset_bounce_map(domain);
> > +     }
> >
> >       down_write(&dev->rwsem);
> >
> > @@ -622,6 +639,31 @@ 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)
> > +             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;
> > +
> > +     write_lock(&dev->groups[group].as_lock);
> > +     dev->groups[group].as = &dev->as[asid];
> > +     write_unlock(&dev->groups[group].as_lock);
> > +
> > +     return 0;
> > +}
> > +
> >  static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
> >                               struct vdpa_vq_state *state)
> >  {
> > @@ -793,13 +835,13 @@ 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;
> >       }
> >
> > @@ -842,6 +884,7 @@ 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,
> >  };
> > @@ -850,32 +893,38 @@ static void vduse_dev_sync_single_for_device(union 
> > virtio_map token,
> >                                            dma_addr_t dma_addr, size_t size,
> >                                            enum dma_data_direction dir)
> >  {
> > -     struct vduse_dev *vdev;
> >       struct vduse_iova_domain *domain;
> >
> >       if (!token.group)
> >               return;
> >
> > -     vdev = token.group->dev;
> > -     domain = vdev->domain;
> > +     if (token.group->dev->nas > 1)
> > +             read_lock(&token.group->as_lock);
> >
> > +     domain = token.group->as->domain;
> >       vduse_domain_sync_single_for_device(domain, dma_addr, size, dir);
> > +
> > +     if (token.group->dev->nas > 1)
> > +             read_unlock(&token.group->as_lock);
> >  }
> >
> >  static void vduse_dev_sync_single_for_cpu(union virtio_map token,
> >                                            dma_addr_t dma_addr, size_t size,
> >                                            enum dma_data_direction dir)
> >  {
> > -     struct vduse_dev *vdev;
> >       struct vduse_iova_domain *domain;
> >
> >       if (!token.group)
> >               return;
> >
> > -     vdev = token.group->dev;
> > -     domain = vdev->domain;
> > +     if (token.group->dev->nas > 1)
> > +             read_lock(&token.group->as_lock);
> >
> > +     domain = token.group->as->domain;
> >       vduse_domain_sync_single_for_cpu(domain, dma_addr, size, dir);
> > +
> > +     if (token.group->dev->nas > 1)
> > +             read_unlock(&token.group->as_lock);
> >  }
> >
> >  static dma_addr_t vduse_dev_map_page(union virtio_map token, struct page 
> > *page,
> > @@ -883,38 +932,45 @@ static dma_addr_t vduse_dev_map_page(union virtio_map 
> > token, struct page *page,
> >                                    enum dma_data_direction dir,
> >                                    unsigned long attrs)
> >  {
> > -     struct vduse_dev *vdev;
> >       struct vduse_iova_domain *domain;
> > +     dma_addr_t r;
> >
> >       if (!token.group)
> >               return DMA_MAPPING_ERROR;
> >
> > -     vdev = token.group->dev;
> > -     domain = vdev->domain;
> > +     if (token.group->dev->nas > 1)
> > +             read_lock(&token.group->as_lock);
> > +     domain = token.group->as->domain;
> > +     r = vduse_domain_map_page(domain, page, offset, size, dir, attrs);
> >
> > -     return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
> > +     if (token.group->dev->nas > 1)
> > +             read_unlock(&token.group->as_lock);
> > +
> > +     return r;
> >  }
> >
> >  static void vduse_dev_unmap_page(union virtio_map token, dma_addr_t 
> > dma_addr,
> >                                size_t size, enum dma_data_direction dir,
> >                                unsigned long attrs)
> >  {
> > -     struct vduse_dev *vdev;
> >       struct vduse_iova_domain *domain;
> >
> >       if (!token.group)
> >               return;
> >
> > -     vdev = token.group->dev;
> > -     domain = vdev->domain;
> > +     if (token.group->dev->nas > 1)
> > +             read_lock(&token.group->as_lock);
> > +
> > +     domain = token.group->as->domain;
> > +     vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
> >
> > -     return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
> > +     if (token.group->dev->nas > 1)
> > +             read_unlock(&token.group->as_lock);
> >  }
> >
> >  static void *vduse_dev_alloc_coherent(union virtio_map token, size_t size,
> >                                     dma_addr_t *dma_addr, gfp_t flag)
> >  {
> > -     struct vduse_dev *vdev;
> >       struct vduse_iova_domain *domain;
> >       unsigned long iova;
> >       void *addr;
> > @@ -927,8 +983,10 @@ static void *vduse_dev_alloc_coherent(union virtio_map 
> > token, size_t size,
> >       if (!addr)
> >               return NULL;
> >
> > -     vdev = token.group->dev;
> > -     domain = vdev->domain;
> > +     if (token.group->dev->nas > 1)
> > +             read_lock(&token.group->as_lock);
> > +
> > +     domain = token.group->as->domain;
> >       addr = vduse_domain_alloc_coherent(domain, size,
> >                                          (dma_addr_t *)&iova, addr);
> >       if (!addr)
> > @@ -936,9 +994,14 @@ static void *vduse_dev_alloc_coherent(union virtio_map 
> > token, size_t size,
> >
> >       *dma_addr = (dma_addr_t)iova;
> >
> > +     if (token.group->dev->nas > 1)
> > +             read_unlock(&token.group->as_lock);
> > +
> >       return addr;
> >
> >  err:
> > +     if (token.group->dev->nas > 1)
> > +             read_unlock(&token.group->as_lock);
> >       free_pages_exact(addr, size);
> >       return NULL;
> >  }
> > @@ -947,31 +1010,39 @@ static void vduse_dev_free_coherent(union virtio_map 
> > token, size_t size,
> >                                   void *vaddr, dma_addr_t dma_addr,
> >                                   unsigned long attrs)
> >  {
> > -     struct vduse_dev *vdev;
> >       struct vduse_iova_domain *domain;
> >
> >       if (!token.group)
> >               return;
> >
> > -     vdev = token.group->dev;
> > -     domain = vdev->domain;
> > +     if (token.group->dev->nas > 1)
> > +             read_lock(&token.group->as_lock);
> >
> > +     domain = token.group->as->domain;
> >       vduse_domain_free_coherent(domain, size, dma_addr, attrs);
> > +
> > +     if (token.group->dev->nas > 1)
> > +             read_unlock(&token.group->as_lock);
> > +
> >       free_pages_exact(vaddr, size);
> >  }
> >
> >  static bool vduse_dev_need_sync(union virtio_map token, dma_addr_t 
> > dma_addr)
> >  {
> > -     struct vduse_dev *vdev;
> > -     struct vduse_iova_domain *domain;
> > +     size_t bounce_size;
> >
> >       if (!token.group)
> >               return false;
> >
> > -     vdev = token.group->dev;
> > -     domain = vdev->domain;
> > +     if (token.group->dev->nas > 1)
> > +             read_lock(&token.group->as_lock);
> > +
> > +     bounce_size = token.group->as->domain->bounce_size;
> > +
> > +     if (token.group->dev->nas > 1)
> > +             read_unlock(&token.group->as_lock);
> >
> > -     return dma_addr < domain->bounce_size;
> > +     return dma_addr < bounce_size;
> >  }
> >
> >  static int vduse_dev_mapping_error(union virtio_map token, dma_addr_t 
> > dma_addr)
> > @@ -983,16 +1054,20 @@ static int vduse_dev_mapping_error(union virtio_map 
> > token, dma_addr_t dma_addr)
> >
> >  static size_t vduse_dev_max_mapping_size(union virtio_map token)
> >  {
> > -     struct vduse_dev *vdev;
> > -     struct vduse_iova_domain *domain;
> > +     size_t bounce_size;
> >
> >       if (!token.group)
> >               return 0;
> >
> > -     vdev = token.group->dev;
> > -     domain = vdev->domain;
> > +     if (token.group->dev->nas > 1)
> > +             read_lock(&token.group->as_lock);
> > +
> > +     bounce_size = token.group->as->domain->bounce_size;
> > +
> > +     if (token.group->dev->nas > 1)
> > +             read_unlock(&token.group->as_lock);
> >
> > -     return domain->bounce_size;
> > +     return bounce_size;
> >  }
> >
> >  static const struct virtio_map_ops vduse_map_ops = {
> > @@ -1132,39 +1207,40 @@ static int vduse_dev_queue_irq_work(struct 
> > vduse_dev *dev,
> >       return ret;
> >  }
> >
> > -static int vduse_dev_dereg_umem(struct vduse_dev *dev,
> > +static int vduse_dev_dereg_umem(struct vduse_dev *dev, u32 asid,
> >                               u64 iova, u64 size)
> >  {
> >       int ret;
> >
> > -     mutex_lock(&dev->mem_lock);
> > +     mutex_lock(&dev->as[asid].mem_lock);
> >       ret = -ENOENT;
> > -     if (!dev->umem)
> > +     if (!dev->as[asid].umem)
> >               goto unlock;
> >
> >       ret = -EINVAL;
> > -     if (!dev->domain)
> > +     if (!dev->as[asid].domain)
> >               goto unlock;
> >
> > -     if (dev->umem->iova != iova || size != dev->domain->bounce_size)
> > +     if (dev->as[asid].umem->iova != iova ||
> > +         size != dev->as[asid].domain->bounce_size)
> >               goto unlock;
> >
> > -     vduse_domain_remove_user_bounce_pages(dev->domain);
> > -     unpin_user_pages_dirty_lock(dev->umem->pages,
> > -                                 dev->umem->npages, true);
> > -     atomic64_sub(dev->umem->npages, &dev->umem->mm->pinned_vm);
> > -     mmdrop(dev->umem->mm);
> > -     vfree(dev->umem->pages);
> > -     kfree(dev->umem);
> > -     dev->umem = NULL;
> > +     vduse_domain_remove_user_bounce_pages(dev->as[asid].domain);
> > +     unpin_user_pages_dirty_lock(dev->as[asid].umem->pages,
> > +                                 dev->as[asid].umem->npages, true);
> > +     atomic64_sub(dev->as[asid].umem->npages, 
> > &dev->as[asid].umem->mm->pinned_vm);
> > +     mmdrop(dev->as[asid].umem->mm);
> > +     vfree(dev->as[asid].umem->pages);
> > +     kfree(dev->as[asid].umem);
> > +     dev->as[asid].umem = NULL;
> >       ret = 0;
> >  unlock:
> > -     mutex_unlock(&dev->mem_lock);
> > +     mutex_unlock(&dev->as[asid].mem_lock);
> >       return ret;
> >  }
> >
> >  static int vduse_dev_reg_umem(struct vduse_dev *dev,
> > -                           u64 iova, u64 uaddr, u64 size)
> > +                           u32 asid, u64 iova, u64 uaddr, u64 size)
> >  {
> >       struct page **page_list = NULL;
> >       struct vduse_umem *umem = NULL;
> > @@ -1172,14 +1248,14 @@ static int vduse_dev_reg_umem(struct vduse_dev *dev,
> >       unsigned long npages, lock_limit;
> >       int ret;
> >
> > -     if (!dev->domain || !dev->domain->bounce_map ||
> > -         size != dev->domain->bounce_size ||
> > +     if (!dev->as[asid].domain || !dev->as[asid].domain->bounce_map ||
> > +         size != dev->as[asid].domain->bounce_size ||
> >           iova != 0 || uaddr & ~PAGE_MASK)
> >               return -EINVAL;
> >
> > -     mutex_lock(&dev->mem_lock);
> > +     mutex_lock(&dev->as[asid].mem_lock);
> >       ret = -EEXIST;
> > -     if (dev->umem)
> > +     if (dev->as[asid].umem)
> >               goto unlock;
> >
> >       ret = -ENOMEM;
> > @@ -1203,7 +1279,7 @@ static int vduse_dev_reg_umem(struct vduse_dev *dev,
> >               goto out;
> >       }
> >
> > -     ret = vduse_domain_add_user_bounce_pages(dev->domain,
> > +     ret = vduse_domain_add_user_bounce_pages(dev->as[asid].domain,
> >                                                page_list, pinned);
> >       if (ret)
> >               goto out;
> > @@ -1216,7 +1292,7 @@ static int vduse_dev_reg_umem(struct vduse_dev *dev,
> >       umem->mm = current->mm;
> >       mmgrab(current->mm);
> >
> > -     dev->umem = umem;
> > +     dev->as[asid].umem = umem;
> >  out:
> >       if (ret && pinned > 0)
> >               unpin_user_pages(page_list, pinned);
> > @@ -1227,7 +1303,7 @@ static int vduse_dev_reg_umem(struct vduse_dev *dev,
> >               vfree(page_list);
> >               kfree(umem);
> >       }
> > -     mutex_unlock(&dev->mem_lock);
> > +     mutex_unlock(&dev->as[asid].mem_lock);
> >       return ret;
> >  }
> >
> > @@ -1248,43 +1324,46 @@ static void vduse_vq_update_effective_cpu(struct 
> > vduse_virtqueue *vq)
> >  }
> >
> >  static int vduse_dev_iotlb_entry(struct vduse_dev *dev,
> > -                              struct vduse_iotlb_entry *entry,
> > +                              struct vduse_iotlb_entry_v2 *entry,
> >                                struct file **f, uint64_t *capability)
> >  {
> > +     u32 asid;
> >       int r = -EINVAL;
> >       struct vhost_iotlb_map *map;
> >       const struct vdpa_map_file *map_file;
> >
> > -     if (entry->start > entry->last)
> > +     if (entry->v1.start > entry->v1.last || entry->asid >= dev->nas)
> >               return -EINVAL;
> >
> > +     asid = array_index_nospec(entry->asid, dev->nas);
> >       mutex_lock(&dev->domain_lock);
> > -     if (!dev->domain)
> > +
> > +     if (!dev->as[asid].domain)
> >               goto out;
> >
> > -     spin_lock(&dev->domain->iotlb_lock);
> > -     map = vhost_iotlb_itree_first(dev->domain->iotlb, entry->start,
> > -                                   entry->last);
> > +     spin_lock(&dev->as[asid].domain->iotlb_lock);
> > +     map = vhost_iotlb_itree_first(dev->as[asid].domain->iotlb,
> > +                                   entry->v1.start, entry->v1.last);
> >       if (map) {
> >               if (f) {
> >                       map_file = (struct vdpa_map_file *)map->opaque;
> >                       *f = get_file(map_file->file);
> >               }
> > -             entry->offset = map_file->offset;
> > -             entry->start = map->start;
> > -             entry->last = map->last;
> > -             entry->perm = map->perm;
> > +             entry->v1.offset = map_file->offset;
> > +             entry->v1.start = map->start;
> > +             entry->v1.last = map->last;
> > +             entry->v1.perm = map->perm;
> >               if (capability) {
> >                       *capability = 0;
> >
> > -                     if (dev->domain->bounce_map && map->start == 0 &&
> > -                         map->last == dev->domain->bounce_size - 1)
> > +                     if (dev->as[asid].domain->bounce_map && map->start == 
> > 0 &&
> > +                         map->last == dev->as[asid].domain->bounce_size - 
> > 1)
> >                               *capability |= VDUSE_IOVA_CAP_UMEM;
> >               }
> >
> >               r = 0;
> >       }
> > -     spin_unlock(&dev->domain->iotlb_lock);
> > +     spin_unlock(&dev->as[asid].domain->iotlb_lock);
> >
> >  out:
> >       mutex_unlock(&dev->domain_lock);
> > @@ -1302,12 +1381,29 @@ static long vduse_dev_ioctl(struct file *file, 
> > unsigned int cmd,
> >               return -EPERM;
> >
> >       switch (cmd) {
> > -     case VDUSE_IOTLB_GET_FD: {
> > -             struct vduse_iotlb_entry entry;
> > +     case VDUSE_IOTLB_GET_FD:
> > +     case VDUSE_IOTLB_GET_FD2: {
> > +             struct vduse_iotlb_entry_v2 entry = {0};
> >               struct file *f = NULL;
> >
> > +             ret = -ENOIOCTLCMD;
> > +             if (dev->api_version < VDUSE_API_VERSION_1 &&
> > +                 cmd == VDUSE_IOTLB_GET_FD2)
> > +                     break;
> > +
> >               ret = -EFAULT;
> > -             if (copy_from_user(&entry, argp, sizeof(entry)))
> > +             if (cmd == VDUSE_IOTLB_GET_FD2) {
> > +                     if (copy_from_user(&entry, argp, sizeof(entry)))
> > +                             break;
> > +             } else {
> > +                     if (copy_from_user(&entry.v1, argp,
> > +                                        sizeof(entry.v1)))
> > +                             break;
> > +             }
> > +
> > +             ret = -EINVAL;
> > +             if (!is_mem_zero((const char *)entry.reserved,
> > +                              sizeof(entry.reserved)))
> >                       break;
> >
> >               ret = vduse_dev_iotlb_entry(dev, &entry, &f, NULL);
> > @@ -1318,12 +1414,19 @@ static long vduse_dev_ioctl(struct file *file, 
> > unsigned int cmd,
> >               if (!f)
> >                       break;
> >
> > -             ret = -EFAULT;
> > -             if (copy_to_user(argp, &entry, sizeof(entry))) {
> > +             if (cmd == VDUSE_IOTLB_GET_FD2)
> > +                     ret = copy_to_user(argp, &entry,
> > +                                        sizeof(entry));
> > +             else
> > +                     ret = copy_to_user(argp, &entry.v1,
> > +                                        sizeof(entry.v1));
> > +
> > +             if (ret) {
> > +                     ret = -EFAULT;
> >                       fput(f);
> >                       break;
> >               }
> > -             ret = receive_fd(f, NULL, perm_to_file_flags(entry.perm));
> > +             ret = receive_fd(f, NULL, perm_to_file_flags(entry.v1.perm));
> >               fput(f);
> >               break;
> >       }
> > @@ -1468,6 +1571,7 @@ static long vduse_dev_ioctl(struct file *file, 
> > unsigned int cmd,
> >       }
> >       case VDUSE_IOTLB_REG_UMEM: {
> >               struct vduse_iova_umem umem;
> > +             u32 asid;
> >
> >               ret = -EFAULT;
> >               if (copy_from_user(&umem, argp, sizeof(umem)))
> > @@ -1475,17 +1579,21 @@ static long vduse_dev_ioctl(struct file *file, 
> > unsigned int cmd,
> >
> >               ret = -EINVAL;
> >               if (!is_mem_zero((const char *)umem.reserved,
> > -                              sizeof(umem.reserved)))
> > +                              sizeof(umem.reserved)) ||
> > +                 (dev->api_version < VDUSE_API_VERSION_1 &&
> > +                  umem.asid != 0) || umem.asid >= dev->nas)
> >                       break;
> >
> >               mutex_lock(&dev->domain_lock);
> > -             ret = vduse_dev_reg_umem(dev, umem.iova,
> > +             asid = array_index_nospec(umem.asid, dev->nas);
> > +             ret = vduse_dev_reg_umem(dev, asid, umem.iova,
> >                                        umem.uaddr, umem.size);
> >               mutex_unlock(&dev->domain_lock);
> >               break;
> >       }
> >       case VDUSE_IOTLB_DEREG_UMEM: {
> >               struct vduse_iova_umem umem;
> > +             u32 asid;
> >
> >               ret = -EFAULT;
> >               if (copy_from_user(&umem, argp, sizeof(umem)))
> > @@ -1493,17 +1601,22 @@ static long vduse_dev_ioctl(struct file *file, 
> > unsigned int cmd,
> >
> >               ret = -EINVAL;
> >               if (!is_mem_zero((const char *)umem.reserved,
> > -                              sizeof(umem.reserved)))
> > +                              sizeof(umem.reserved)) ||
> > +                 (dev->api_version < VDUSE_API_VERSION_1 &&
> > +                  umem.asid != 0) ||
> > +                  umem.asid >= dev->nas)
> >                       break;
> > +
> >               mutex_lock(&dev->domain_lock);
> > -             ret = vduse_dev_dereg_umem(dev, umem.iova,
> > +             asid = array_index_nospec(umem.asid, dev->nas);
> > +             ret = vduse_dev_dereg_umem(dev, asid, umem.iova,
> >                                          umem.size);
> >               mutex_unlock(&dev->domain_lock);
> >               break;
> >       }
> >       case VDUSE_IOTLB_GET_INFO: {
> >               struct vduse_iova_info info;
> > -             struct vduse_iotlb_entry entry;
> > +             struct vduse_iotlb_entry_v2 entry;
> >
> >               ret = -EFAULT;
> >               if (copy_from_user(&info, argp, sizeof(info)))
> > @@ -1513,15 +1626,23 @@ static long vduse_dev_ioctl(struct file *file, 
> > unsigned int cmd,
> >                                sizeof(info.reserved)))
> >                       break;
> >
> > -             entry.start = info.start;
> > -             entry.last = info.last;
> > +             if (dev->api_version < VDUSE_API_VERSION_1) {
> > +                     if (info.asid)
> > +                             break;
> > +             } else if (info.asid >= dev->nas)
> > +                     break;
> > +
> > +             entry.v1.start = info.start;
> > +             entry.v1.last = info.last;
> > +             entry.asid = info.asid;
> >               ret = vduse_dev_iotlb_entry(dev, &entry, NULL,
> >                                           &info.capability);
> >               if (ret < 0)
> >                       break;
> >
> > -             info.start = entry.start;
> > -             info.last = entry.last;
> > +             info.start = entry.v1.start;
> > +             info.last = entry.v1.last;
> > +             info.asid = entry.asid;
> >
> >               ret = -EFAULT;
> >               if (copy_to_user(argp, &info, sizeof(info)))
> > @@ -1543,8 +1664,10 @@ static int vduse_dev_release(struct inode *inode, 
> > struct file *file)
> >       struct vduse_dev *dev = file->private_data;
> >
> >       mutex_lock(&dev->domain_lock);
> > -     if (dev->domain)
> > -             vduse_dev_dereg_umem(dev, 0, dev->domain->bounce_size);
> > +     for (int i = 0; i < dev->nas; i++)
> > +             if (dev->as[i].domain)
> > +                     vduse_dev_dereg_umem(dev, i, 0,
> > +                                          dev->as[i].domain->bounce_size);
> >       mutex_unlock(&dev->domain_lock);
> >       spin_lock(&dev->msg_lock);
> >       /* Make sure the inflight messages can processed after reconncection 
> > */
> > @@ -1763,7 +1886,6 @@ static struct vduse_dev *vduse_dev_create(void)
> >               return NULL;
> >
> >       mutex_init(&dev->lock);
> > -     mutex_init(&dev->mem_lock);
> >       mutex_init(&dev->domain_lock);
> >       spin_lock_init(&dev->msg_lock);
> >       INIT_LIST_HEAD(&dev->send_list);
> > @@ -1814,8 +1936,11 @@ static int vduse_destroy_dev(char *name)
> >       idr_remove(&vduse_idr, dev->minor);
> >       kvfree(dev->config);
> >       vduse_dev_deinit_vqs(dev);
> > -     if (dev->domain)
> > -             vduse_domain_destroy(dev->domain);
> > +     for (int i = 0; i < dev->nas; i++) {
> > +             if (dev->as[i].domain)
> > +                     vduse_domain_destroy(dev->as[i].domain);
> > +     }
> > +     kfree(dev->as);
> >       kfree(dev->name);
> >       kfree(dev->groups);
> >       vduse_dev_destroy(dev);
> > @@ -1862,12 +1987,17 @@ static bool vduse_validate_config(struct 
> > vduse_dev_config *config,
> >                        sizeof(config->reserved)))
> >               return false;
> >
> > -     if (api_version < VDUSE_API_VERSION_1 && config->ngroups)
> > +     if (api_version < VDUSE_API_VERSION_1 &&
> > +         (config->ngroups || config->nas))
> >               return false;
> >
> > -     if (api_version >= VDUSE_API_VERSION_1 &&
> > -         (!config->ngroups || config->ngroups > VDUSE_DEV_MAX_GROUPS))
> > -             return false;
> > +     if (api_version >= VDUSE_API_VERSION_1) {
> > +             if (!config->ngroups || config->ngroups > 
> > VDUSE_DEV_MAX_GROUPS)
> > +                     return false;
> > +
> > +             if (!config->nas || config->nas > VDUSE_DEV_MAX_AS)
> > +                     return false;
> > +     }
> >
> >       if (config->vq_align > PAGE_SIZE)
> >               return false;
> > @@ -1932,7 +2062,8 @@ static ssize_t bounce_size_store(struct device 
> > *device,
> >
> >       ret = -EPERM;
> >       mutex_lock(&dev->domain_lock);
> > -     if (dev->domain)
> > +     /* Assuming that if the first domain is allocated, all are allocated 
> > */
> > +     if (dev->as[0].domain)
> >               goto unlock;
> >
> >       ret = kstrtouint(buf, 10, &bounce_size);
> > @@ -1984,6 +2115,14 @@ static int vduse_create_dev(struct vduse_dev_config 
> > *config,
> >       dev->device_features = config->features;
> >       dev->device_id = config->device_id;
> >       dev->vendor_id = config->vendor_id;
> > +
> > +     dev->nas = (dev->api_version < VDUSE_API_VERSION_1) ? 1 : config->nas;
> > +     dev->as = kcalloc(dev->nas, sizeof(dev->as[0]), GFP_KERNEL);
> > +     if (!dev->as)
> > +             goto err_as;
> > +     for (int i = 0; i < dev->nas; i++)
> > +             mutex_init(&dev->as[i].mem_lock);
> > +
> >       dev->ngroups = (dev->api_version < VDUSE_API_VERSION_1)
> >                      ? 1
> >                      : config->ngroups;
> > @@ -1991,8 +2130,11 @@ static int vduse_create_dev(struct vduse_dev_config 
> > *config,
> >                             GFP_KERNEL);
> >       if (!dev->groups)
> >               goto err_vq_groups;
> > -     for (u32 i = 0; i < dev->ngroups; ++i)
> > +     for (u32 i = 0; i < dev->ngroups; ++i) {
> >               dev->groups[i].dev = dev;
> > +             rwlock_init(&dev->groups[i].as_lock);
> > +             dev->groups[i].as = &dev->as[0];
> > +     }
> >
> >       dev->name = kstrdup(config->name, GFP_KERNEL);
> >       if (!dev->name)
> > @@ -2032,6 +2174,8 @@ static int vduse_create_dev(struct vduse_dev_config 
> > *config,
> >  err_str:
> >       kfree(dev->groups);
> >  err_vq_groups:
> > +     kfree(dev->as);
> > +err_as:
> >       vduse_dev_destroy(dev);
> >  err:
> >       return ret;
> > @@ -2155,7 +2299,7 @@ static int vduse_dev_init_vdpa(struct vduse_dev *dev, 
> > const char *name)
> >
> >       vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, dev->dev,
> >                                &vduse_vdpa_config_ops, &vduse_map_ops,
> > -                              dev->ngroups, 1, name, true);
> > +                              dev->ngroups, dev->nas, name, true);
> >       if (IS_ERR(vdev))
> >               return PTR_ERR(vdev);
> >
> > @@ -2170,7 +2314,8 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, 
> > const char *name,
> >                       const struct vdpa_dev_set_config *config)
> >  {
> >       struct vduse_dev *dev;
> > -     int ret;
> > +     size_t domain_bounce_size;
> > +     int ret, i;
> >
> >       mutex_lock(&vduse_lock);
> >       dev = vduse_find_dev(name);
> > @@ -2184,29 +2329,38 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, 
> > const char *name,
> >               return ret;
> >
> >       mutex_lock(&dev->domain_lock);
> > -     if (!dev->domain)
> > -             dev->domain = vduse_domain_create(VDUSE_IOVA_SIZE - 1,
> > -                                               dev->bounce_size);
> > -     mutex_unlock(&dev->domain_lock);
> > -     if (!dev->domain) {
> > -             ret = -ENOMEM;
> > -             goto domain_err;
> > +     ret = 0;
> > +
> > +     domain_bounce_size = dev->bounce_size / dev->nas;
> > +     for (i = 0; i < dev->nas; ++i) {
> > +             dev->as[i].domain = vduse_domain_create(VDUSE_IOVA_SIZE - 1,
> > +                                                     domain_bounce_size);
> > +             if (!dev->as[i].domain) {
> > +                     ret = -ENOMEM;
> > +                     goto err;
> > +             }
> >       }
> >
> > +     mutex_unlock(&dev->domain_lock);
> > +
> >       ret = _vdpa_register_device(&dev->vdev->vdpa, dev->vq_num);
> > -     if (ret) {
> > -             goto register_err;
> > -     }
> > +     if (ret)
> > +             goto err_register;
> >
> >       return 0;
> >
> > -register_err:
> > +err_register:
> >       mutex_lock(&dev->domain_lock);
> > -     vduse_domain_destroy(dev->domain);
> > -     dev->domain = NULL;
> > +
> > +err:
> > +     for (int j = 0; j < i; j++) {
> > +             if (dev->as[j].domain) {
> > +                     vduse_domain_destroy(dev->as[j].domain);
> > +                     dev->as[j].domain = NULL;
> > +             }
> > +     }
> >       mutex_unlock(&dev->domain_lock);
> >
> > -domain_err:
> >       put_device(&dev->vdev->vdpa.dev);
> >
> >       return ret;
> > diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> > index a3d51cf6df3a..9e423163d819 100644
> > --- a/include/uapi/linux/vduse.h
> > +++ b/include/uapi/linux/vduse.h
> > @@ -47,7 +47,8 @@ struct vduse_dev_config {
> >       __u32 vq_num;
> >       __u32 vq_align;
> >       __u32 ngroups; /* if VDUSE_API_VERSION >= 1 */
> > -     __u32 reserved[12];
> > +     __u32 nas; /* if VDUSE_API_VERSION >= 1 */
> > +     __u32 reserved[11];
> >       __u32 config_size;
> >       __u8 config[];
> >  };
> > @@ -166,6 +167,16 @@ struct vduse_vq_state_packed {
> >       __u16 last_used_idx;
> >  };
> >
> > +/**
> > + * struct vduse_vq_group_asid - virtqueue group ASID
> > + * @group: Index of the virtqueue group
> > + * @asid: Address space ID of the group
> > + */
> > +struct vduse_vq_group_asid {
> > +     __u32 group;
> > +     __u32 asid;
> > +};
> > +
> >  /**
> >   * struct vduse_vq_info - information of a virtqueue
> >   * @index: virtqueue index
> > @@ -225,6 +236,7 @@ struct vduse_vq_eventfd {
> >   * @uaddr: start address of userspace memory, it must be aligned to page 
> > size
> >   * @iova: start of the IOVA region
> >   * @size: size of the IOVA region
> > + * @asid: Address space ID of the IOVA region
> >   * @reserved: for future use, needs to be initialized to zero
> >   *
> >   * Structure used by VDUSE_IOTLB_REG_UMEM and VDUSE_IOTLB_DEREG_UMEM
> > @@ -234,7 +246,8 @@ struct vduse_iova_umem {
> >       __u64 uaddr;
> >       __u64 iova;
> >       __u64 size;
> > -     __u64 reserved[3];
> > +     __u32 asid;
> > +     __u32 reserved[5];
> >  };
> >
> >  /* Register userspace memory for IOVA regions */
> > @@ -248,6 +261,7 @@ struct vduse_iova_umem {
> >   * @start: start of the IOVA region
> >   * @last: last of the IOVA region
> >   * @capability: capability of the IOVA region
> > + * @asid: Address space ID of the IOVA region, only if device API version 
> > >= 1
> >   * @reserved: for future use, needs to be initialized to zero
> >   *
> >   * Structure used by VDUSE_IOTLB_GET_INFO ioctl to get information of
> > @@ -258,7 +272,8 @@ struct vduse_iova_info {
> >       __u64 last;
> >  #define VDUSE_IOVA_CAP_UMEM (1 << 0)
> >       __u64 capability;
> > -     __u64 reserved[3];
> > +     __u32 asid; /* Only if device API version >= 1 */
> > +     __u32 reserved[5];
> >  };
> >
> >  /*
> > @@ -267,6 +282,28 @@ struct vduse_iova_info {
> >   */
> >  #define VDUSE_IOTLB_GET_INFO _IOWR(VDUSE_BASE, 0x1a, struct 
> > vduse_iova_info)
> >
> > +/**
> > + * struct vduse_iotlb_entry_v2 - entry of IOTLB to describe one IOVA region
> > + *
> > + * @v1: the original vduse_iotlb_entry
> > + * @asid: address space ID of the IOVA region
> > + * @reserver: for future use, needs to be initialized to zero
> > + *
> > + * Structure used by VDUSE_IOTLB_GET_FD2 ioctl to find an overlapped IOVA 
> > region.
> > + */
> > +struct vduse_iotlb_entry_v2 {
> > +     struct vduse_iotlb_entry v1;
> > +     __u32 asid;
> > +     __u32 reserved[12];
> > +};
> > +
> > +/*
> > + * Same as VDUSE_IOTLB_GET_FD but with vduse_iotlb_entry_v2 argument that
> > + * support extra fields.
> > + */
> > +#define VDUSE_IOTLB_GET_FD2  _IOWR(VDUSE_BASE, 0x1b, struct 
> > vduse_iotlb_entry_v2)
> > +
> > +
> >  /* The control messages definition for read(2)/write(2) on 
> > /dev/vduse/$NAME */
> >
> >  /**
> > @@ -280,6 +317,7 @@ enum vduse_req_type {
> >       VDUSE_GET_VQ_STATE,
> >       VDUSE_SET_STATUS,
> >       VDUSE_UPDATE_IOTLB,
> > +     VDUSE_SET_VQ_GROUP_ASID,
> >  };
> >
> >  /**
> > @@ -314,6 +352,18 @@ struct vduse_iova_range {
> >       __u64 last;
> >  };
> >
> > +/**
> > + * struct vduse_iova_range - IOVA range [start, last] if API_VERSION >= 1
>
> ypu mean struct vduse_iova_range_v2 ?
>

Right, thanks for the catch!


> > + * @start: start of the IOVA range
> > + * @last: last of the IOVA range
> > + * @asid: address space ID of the IOVA range
> > + */
> > +struct vduse_iova_range_v2 {
> > +     __u64 start;
> > +     __u64 last;
> > +     __u32 asid;
> > +};
> > +
> >  /**
> >   * struct vduse_dev_request - control request
> >   * @type: request type
> > @@ -322,6 +372,8 @@ struct vduse_iova_range {
> >   * @vq_state: virtqueue state, only index field is available
> >   * @s: device status
> >   * @iova: IOVA range for updating
> > + * @iova_v2: IOVA range for updating if API_VERSION >= 1
> > + * @vq_group_asid: ASID of a virtqueue group
> >   * @padding: padding
> >   *
> >   * Structure used by read(2) on /dev/vduse/$NAME.
> > @@ -334,6 +386,11 @@ struct vduse_dev_request {
> >               struct vduse_vq_state vq_state;
> >               struct vduse_dev_status s;
> >               struct vduse_iova_range iova;
> > +             /* Following members but padding exist only if vduse api
> > +              * version >= 1
> > +              */;
> > +             struct vduse_iova_range_v2 iova_v2;
> > +             struct vduse_vq_group_asid vq_group_asid;
> >               __u32 padding[32];
> >       };
> >  };
> > --
> > 2.52.0
>


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