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Message-ID: <CACGkMEu2mh7oSVYJnD5R4EYXxtU0_rvXh08xSmGVRgTb7uKLAQ@mail.gmail.com>
Date: Tue, 12 Aug 2025 11:05:26 +0800
From: Jason Wang <jasowang@...hat.com>
To: Eugenio Perez Martin <eperezma@...hat.com>
Cc: "Michael S . Tsirkin" <mst@...hat.com>, Cindy Lu <lulu@...hat.com>,
Yongji Xie <xieyongji@...edance.com>, Stefano Garzarella <sgarzare@...hat.com>,
virtualization@...ts.linux.dev, Laurent Vivier <lvivier@...hat.com>,
linux-kernel@...r.kernel.org, Xuan Zhuo <xuanzhuo@...ux.alibaba.com>,
Maxime Coquelin <mcoqueli@...hat.com>
Subject: Re: [RFC v2 5/7] vduse: add vq group asid support
On Mon, Aug 11, 2025 at 7:20 PM Eugenio Perez Martin
<eperezma@...hat.com> wrote:
>
> On Mon, Aug 11, 2025 at 5:21 AM Jason Wang <jasowang@...hat.com> wrote:
> >
> > On Thu, Aug 7, 2025 at 7:58 PM Eugenio Pérez <eperezma@...hat.com> wrote:
> > >
> > > Add support for assigning Address Space Identifiers (ASIDs) to each VQ
> > > group. This enables mapping each group into a distinct memory space.
> > >
> > > Signed-off-by: Eugenio Pérez <eperezma@...hat.com>
> > > ---
> > > 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 | 259 ++++++++++++++++++++++-------
> > > include/uapi/linux/vduse.h | 36 +++-
> > > 2 files changed, 230 insertions(+), 65 deletions(-)
> > >
> > > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> > > index a7a2749f5818..145147c49930 100644
> > > --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> > > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> > > @@ -51,6 +51,12 @@
> > > */
> > > #define VDUSE_MAX_VQ_GROUPS 3
> > >
> > > +/*
> > > + * We can do ASID thanks to (ab)using the vduse device and the vdpa one. So no
> > > + * more than 2.
> > > + */
> > > +#define VDUSE_MAX_ASID 2
> >
> > Similar to group limitation, I'd like to either make it larger to 64
> > or make it changable via sysfs.
We can start from something that is simple (64).
> >
> > > +
> > > #define IRQ_UNBOUND -1
> > >
> > > struct vduse_virtqueue {
> > > @@ -91,6 +97,7 @@ struct vduse_umem {
> > > };
> > >
> > > struct vduse_vq_group_int {
> > > + struct vduse_iova_domain *domain;
> > > struct vduse_dev *dev;
> > > };
> > >
> > > @@ -98,7 +105,7 @@ struct vduse_dev {
> > > struct vduse_vdpa *vdev;
> > > struct device *dev;
> > > struct vduse_virtqueue **vqs;
> > > - struct vduse_iova_domain *domain;
> > > + struct vduse_iova_domain *domain[VDUSE_MAX_ASID];
> > > char *name;
> > > struct mutex lock;
> > > spinlock_t msg_lock;
> > > @@ -126,7 +133,8 @@ struct vduse_dev {
> > > u32 vq_num;
> > > u32 vq_align;
> > > u32 ngroups;
> > > - struct vduse_umem *umem;
> > > + u32 nas;
> > > + struct vduse_umem *umem[VDUSE_MAX_ASID];
> > > struct vduse_vq_group_int groups[VDUSE_MAX_VQ_GROUPS];
> > > struct mutex mem_lock;
> > > unsigned int bounce_size;
> > > @@ -440,14 +448,28 @@ 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)
> > > +{
> > > + guard(mutex)(&dev->domain_lock);
> > > + dev->groups[group].domain = dev->domain[asid];
> > > +}
> > > +
> > > 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->domain[i];
> > > +
> > > + 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);
> >
> > I vaguely remember Siwei has invented a feature that forbids the reset
> > of the mapping during virtio reset. If it's true, let's check that
> > feature flag.
> >
>
> Ouch, very good catch!
>
> > Btw even if we device to reset the mapping, should it be implied via
> > reset message itself instead of having more operations here?
> >
>
> This was resetting all to valid values by the start of the device
> operation, so no need for a new message at least for now.
>
> > >
> > > down_write(&dev->rwsem);
> > >
> > > @@ -619,6 +641,29 @@ static u32 vduse_get_vq_desc_group(struct vdpa_device *vdpa, u16 idx)
> > > return dev->vqs[idx]->vq_desc_group;
> > > }
> > >
> > > +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;
> >
> > I wonder if this could be part of the shared memory?
> >
>
> I think it complicates the solution a lot, isn't it? How to notify the
> VDUSE device that these properties have changed, what vq group
> changed, etc? What do we want to achieve with the shm solution?
Rethink about this, I think you're right. But the point is to avoid
userspace transaction as much as possible.
>
> > > +
> > > + r = vduse_dev_msg_sync(dev, &msg);
> > > + if (r < 0)
> > > + return r;
> > > +
> > > + vduse_set_group_asid_nomsg(dev, group, asid);
> > > + return 0;
> > > +}
> > > +
> > > static void *vduse_get_vq_map_token(struct vdpa_device *vdpa, u16 idx)
> > > {
> > > struct vduse_dev *dev = vdpa_to_vduse(vdpa);
> > > @@ -833,13 +878,13 @@ 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->domain[asid], iotlb);
> > > if (ret)
> > > return ret;
> > >
> > > ret = vduse_dev_update_iotlb(dev, 0ULL, ULLONG_MAX);
> > > if (ret) {
> > > - vduse_domain_clear_map(dev->domain, iotlb);
> > > + vduse_domain_clear_map(dev->domain[asid], iotlb);
> > > return ret;
> > > }
> > >
> > > @@ -883,6 +928,7 @@ 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_token = vduse_get_vq_map_token,
> > > .free = vduse_vdpa_free,
> > > };
> > > @@ -893,8 +939,10 @@ static void vduse_dev_sync_single_for_device(void *token,
> > > {
> > > struct vduse_vq_group_int *group = token;
> > > struct vduse_dev *vdev = group->dev;
> > > - struct vduse_iova_domain *domain = vdev->domain;
> > > + struct vduse_iova_domain *domain;
> > >
> > > + guard(mutex)(&vdev->domain_lock);
> > > + domain = group->domain;
> > > vduse_domain_sync_single_for_device(domain, dma_addr, size, dir);
> > > }
> > >
> > > @@ -904,8 +952,10 @@ static void vduse_dev_sync_single_for_cpu(void *token,
> > > {
> > > struct vduse_vq_group_int *group = token;
> > > struct vduse_dev *vdev = group->dev;
> > > - struct vduse_iova_domain *domain = vdev->domain;
> > > + struct vduse_iova_domain *domain;
> > >
> > > + guard(mutex)(&vdev->domain_lock);
> > > + domain = group->domain;
> > > vduse_domain_sync_single_for_cpu(domain, dma_addr, size, dir);
> > > }
> > >
> > > @@ -916,8 +966,10 @@ static dma_addr_t vduse_dev_map_page(void *token, struct page *page,
> > > {
> > > struct vduse_vq_group_int *group = token;
> > > struct vduse_dev *vdev = group->dev;
> > > - struct vduse_iova_domain *domain = vdev->domain;
> > > + struct vduse_iova_domain *domain;
> > >
> > > + guard(mutex)(&vdev->domain_lock);
> > > + domain = group->domain;
> > > return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
> > > }
> > >
> > > @@ -927,8 +979,10 @@ static void vduse_dev_unmap_page(void *token, dma_addr_t dma_addr,
> > > {
> > > struct vduse_vq_group_int *group = token;
> > > struct vduse_dev *vdev = group->dev;
> > > - struct vduse_iova_domain *domain = vdev->domain;
> > > + struct vduse_iova_domain *domain;
> > >
> > > + guard(mutex)(&vdev->domain_lock);
> > > + domain = group->domain;
> > > return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
> > > }
> > >
> > > @@ -937,11 +991,13 @@ static void *vduse_dev_alloc_coherent(void *token, size_t size,
> > > {
> > > struct vduse_vq_group_int *group = token;
> > > struct vduse_dev *vdev = group->dev;
> > > - struct vduse_iova_domain *domain = vdev->domain;
> > > + struct vduse_iova_domain *domain;
> > > unsigned long iova;
> > > void *addr;
> > >
> > > *dma_addr = DMA_MAPPING_ERROR;
> > > + guard(mutex)(&vdev->domain_lock);
> > > + domain = group->domain;
> > > addr = vduse_domain_alloc_coherent(domain, size,
> > > (dma_addr_t *)&iova, flag);
> > > if (!addr)
> > > @@ -958,8 +1014,10 @@ static void vduse_dev_free_coherent(void *token, size_t size,
> > > {
> > > struct vduse_vq_group_int *group = token;
> > > struct vduse_dev *vdev = group->dev;
> > > - struct vduse_iova_domain *domain = vdev->domain;
> > > + struct vduse_iova_domain *domain;
> > >
> > > + guard(mutex)(&vdev->domain_lock);
> > > + domain = group->domain;
> > > vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
> > > }
> > >
> > > @@ -967,8 +1025,10 @@ static size_t vduse_dev_max_mapping_size(void *token)
> > > {
> > > struct vduse_vq_group_int *group = token;
> > > struct vduse_dev *vdev = group->dev;
> > > - struct vduse_iova_domain *domain = vdev->domain;
> > > + struct vduse_iova_domain *domain;
> > >
> > > + guard(mutex)(&vdev->domain_lock);
> > > + domain = group->domain;
> > > return domain->bounce_size;
> > > }
> > >
> > > @@ -1107,31 +1167,32 @@ 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);
> > > ret = -ENOENT;
> > > - if (!dev->umem)
> > > + if (!dev->umem[asid])
> > > goto unlock;
> > >
> > > ret = -EINVAL;
> > > - if (!dev->domain)
> > > + if (!dev->domain[asid])
> > > goto unlock;
> > >
> > > - if (dev->umem->iova != iova || size != dev->domain->bounce_size)
> > > + if (dev->umem[asid]->iova != iova ||
> > > + size != dev->domain[asid]->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->domain[asid]);
> > > + unpin_user_pages_dirty_lock(dev->umem[asid]->pages,
> > > + dev->umem[asid]->npages, true);
> > > + atomic64_sub(dev->umem[asid]->npages, &dev->umem[asid]->mm->pinned_vm);
> > > + mmdrop(dev->umem[asid]->mm);
> > > + vfree(dev->umem[asid]->pages);
> > > + kfree(dev->umem[asid]);
> > > + dev->umem[asid] = NULL;
> > > ret = 0;
> > > unlock:
> > > mutex_unlock(&dev->mem_lock);
> > > @@ -1139,7 +1200,7 @@ static int vduse_dev_dereg_umem(struct vduse_dev *dev,
> > > }
> > >
> > > 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;
> > > @@ -1147,14 +1208,14 @@ 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->domain[asid] || !dev->domain[asid]->bounce_map ||
> > > + size != dev->domain[asid]->bounce_size ||
> > > iova != 0 || uaddr & ~PAGE_MASK)
> > > return -EINVAL;
> > >
> > > mutex_lock(&dev->mem_lock);
> > > ret = -EEXIST;
> > > - if (dev->umem)
> > > + if (dev->umem[asid])
> > > goto unlock;
> > >
> > > ret = -ENOMEM;
> > > @@ -1178,7 +1239,7 @@ 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->domain[asid],
> > > page_list, pinned);
> > > if (ret)
> > > goto out;
> > > @@ -1191,7 +1252,7 @@ static int vduse_dev_reg_umem(struct vduse_dev *dev,
> > > umem->mm = current->mm;
> > > mmgrab(current->mm);
> > >
> > > - dev->umem = umem;
> > > + dev->umem[asid] = umem;
> > > out:
> > > if (ret && pinned > 0)
> > > unpin_user_pages(page_list, pinned);
> > > @@ -1234,26 +1295,43 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
> > >
> > > switch (cmd) {
> > > case VDUSE_IOTLB_GET_FD: {
> > > - struct vduse_iotlb_entry entry;
> > > + struct vduse_iotlb_entry_v2 entry;
> > > + struct vduse_iotlb_entry entry_old;
> > > struct vhost_iotlb_map *map;
> > > struct vdpa_map_file *map_file;
> > > struct file *f = NULL;
> > >
> > > ret = -EFAULT;
> > > - if (copy_from_user(&entry, argp, sizeof(entry)))
> > > - break;
> > > + if (dev->api_version >= VDUSE_API_VERSION_1) {
> > > + if (copy_from_user(&entry, argp, sizeof(entry)))
> > > + break;
> > > + } else {
> > > + if (copy_from_user(&entry_old, argp,
> > > + sizeof(entry_old)))
> > > + break;
> > > +
> > > + entry.offset = entry_old.offset;
> > > + entry.start = entry_old.start;
> > > + entry.last = entry_old.last;
> > > + entry.asid = 0;
> > > + entry.perm = entry_old.perm;
> > > + }
> > >
> > > ret = -EINVAL;
> > > if (entry.start > entry.last)
> > > break;
> > >
> > > + if (entry.asid > dev->nas)
> > > + break;
> > > +
> > > mutex_lock(&dev->domain_lock);
> > > - if (!dev->domain) {
> > > + /* TODO accessing an array with idx from userspace, mitigations? */
> > > + if (!dev->domain[entry.asid]) {
> > > mutex_unlock(&dev->domain_lock);
> > > break;
> > > }
> > > - spin_lock(&dev->domain->iotlb_lock);
> > > - map = vhost_iotlb_itree_first(dev->domain->iotlb,
> > > + spin_lock(&dev->domain[entry.asid]->iotlb_lock);
> > > + map = vhost_iotlb_itree_first(dev->domain[entry.asid]->iotlb,
> > > entry.start, entry.last);
> > > if (map) {
> > > map_file = (struct vdpa_map_file *)map->opaque;
> > > @@ -1263,7 +1341,7 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
> > > entry.last = map->last;
> > > entry.perm = map->perm;
> > > }
> > > - spin_unlock(&dev->domain->iotlb_lock);
> > > + spin_unlock(&dev->domain[entry.asid]->iotlb_lock);
> > > mutex_unlock(&dev->domain_lock);
> > > ret = -EINVAL;
> > > if (!f)
> > > @@ -1413,12 +1491,16 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
> > > break;
> > >
> > > ret = -EINVAL;
> > > + /* TODO: Using asid from userspace, need to mitigate? */
> > > 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,
> > > + ret = vduse_dev_reg_umem(dev, umem.asid, umem.iova,
> > > umem.uaddr, umem.size);
> > > mutex_unlock(&dev->domain_lock);
> > > break;
> > > @@ -1431,15 +1513,24 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
> > > break;
> > >
> > > ret = -EINVAL;
> > > + /* TODO: Using asid from userspace, need to mitigate? */
> > > 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;
> > > +
> > > +
> > > + if (umem.asid > dev->nas)
> > > break;
> > > mutex_lock(&dev->domain_lock);
> > > - ret = vduse_dev_dereg_umem(dev, umem.iova,
> > > + ret = vduse_dev_dereg_umem(dev, umem.asid, umem.iova,
> > > umem.size);
> > > mutex_unlock(&dev->domain_lock);
> > > break;
> > > }
> > > + /* TODO can we merge this with GET_FD? */
> >
> > Probably but might be too late.
> >
>
> Yep I should just remove this TODO actually.
>
> > > case VDUSE_IOTLB_GET_INFO: {
> > > struct vduse_iova_info info;
> > > struct vhost_iotlb_map *map;
> > > @@ -1452,27 +1543,32 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
> > > if (info.start > info.last)
> > > break;
> > >
> > > + if (info.asid > dev->nas)
> > > + break;
> > > +
> > > if (!is_mem_zero((const char *)info.reserved,
> > > sizeof(info.reserved)))
> > > break;
> > >
> > > mutex_lock(&dev->domain_lock);
> > > - if (!dev->domain) {
> > > + /* TODO asid comes from userspace. mitigations? */
> >
> > We should do sanity check to avoid OOB at least?
> >
>
> There is an if (info.asid > dev->nas) break above, what is missing?
Ok I get, so what you want is array_index_nospec()?
>
> > > + if (!dev->domain[info.asid]) {
> > > mutex_unlock(&dev->domain_lock);
> > > break;
> > > }
> > > - spin_lock(&dev->domain->iotlb_lock);
> > > - map = vhost_iotlb_itree_first(dev->domain->iotlb,
> > > + spin_lock(&dev->domain[info.asid]->iotlb_lock);
> > > + map = vhost_iotlb_itree_first(dev->domain[info.asid]->iotlb,
> > > info.start, info.last);
> > > if (map) {
> > > info.start = map->start;
> > > info.last = map->last;
> > > info.capability = 0;
> > > - if (dev->domain->bounce_map && map->start == 0 &&
> > > - map->last == dev->domain->bounce_size - 1)
> > > + if (dev->domain[info.asid]->bounce_map &&
> > > + map->start == 0 &&
> > > + map->last == dev->domain[info.asid]->bounce_size - 1)
> > > info.capability |= VDUSE_IOVA_CAP_UMEM;
> > > }
> > > - spin_unlock(&dev->domain->iotlb_lock);
> > > + spin_unlock(&dev->domain[info.asid]->iotlb_lock);
> > > mutex_unlock(&dev->domain_lock);
> > > if (!map)
> > > break;
> > > @@ -1497,8 +1593,13 @@ 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->domain[i]) {
> > > + vduse_dev_dereg_umem(dev, i, 0,
> > > + dev->domain[i]->bounce_size);
> > > + dev->domain[i] = NULL;
> > > + }
> > > + }
> > > mutex_unlock(&dev->domain_lock);
> > > spin_lock(&dev->msg_lock);
> > > /* Make sure the inflight messages can processed after reconncection */
> > > @@ -1768,9 +1869,12 @@ 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->domain[i])
> > > + vduse_domain_destroy(dev->domain[i]);
> > > + }
> > > kfree(dev->name);
> > > + kfree(dev->umem);
> > > vduse_dev_destroy(dev);
> > > module_put(THIS_MODULE);
> > >
> > > @@ -1877,7 +1981,8 @@ 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->domain[0])
> > > goto unlock;
> > >
> > > ret = kstrtouint(buf, 10, &bounce_size);
> > > @@ -1933,11 +2038,20 @@ static int vduse_create_dev(struct vduse_dev_config *config,
> > > if (config->ngroups > VDUSE_MAX_VQ_GROUPS) {
> > > pr_err("Not creating a VDUSE device with %u vq groups. Max: %u",
> > > config->ngroups, VDUSE_MAX_VQ_GROUPS);
> > > + /* TODO: Need to destroy dev here too! */
> > > goto err;
> > > }
> > > + if (config->nas > VDUSE_MAX_ASID) {
> > > + pr_err("Not creating a VDUSE device with %u asid. Max: %u",
> > > + config->nas, VDUSE_MAX_ASID);
> > > + goto err_nas;
> > > + }
> > > +
> > > dev->ngroups = config->ngroups ?: 1;
> > > + dev->nas = config->nas ?: 1;
> > > } else {
> > > dev->ngroups = 1;
> > > + dev->nas = 1;
> > > }
> > > for (u32 i = 0; i < dev->ngroups; ++i)
> > > dev->groups[i].dev = dev;
> > > @@ -1977,6 +2091,7 @@ static int vduse_create_dev(struct vduse_dev_config *config,
> > > err_idr:
> > > kfree(dev->name);
> > > err_str:
> > > +err_nas:
> > > vduse_dev_destroy(dev);
> > > err:
> > > return ret;
> > > @@ -2069,7 +2184,6 @@ static int vduse_open(struct inode *inode, struct file *file)
> > > if (!control)
> > > return -ENOMEM;
> > >
> > > - control->api_version = VDUSE_API_VERSION;
> > > file->private_data = control;
> > >
> > > return 0;
> > > @@ -2101,7 +2215,7 @@ 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);
> > >
> > > @@ -2137,11 +2251,23 @@ 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);
> > > + ret = 0;
> > > +
> > > + /* TODO we could delay the creation of the domain */
> >
> > I don't get what this means?
> >
>
> If the device support all 64 asid but it never uses them we're
> consuming the memory for all the struct vduse_iova_domain, struct
> vduse_umem, etc. We could delay its creating until we start using it,
> but it complicates the code.
If it doesn't takes too much memory, we can start from a static
allocation (if that's what you meant here).
>
> > > + for (int i = 0; i < dev->nas; ++i) {
> > > + if (!dev->domain[i])
> > > + dev->domain[i] = vduse_domain_create(VDUSE_IOVA_SIZE - 1,
> > > + dev->bounce_size);
> > > + if (!dev->domain[i]) {
> > > + ret = -ENOMEM;
> > > + for (int j = 0; j < i; ++j)
> > > + vduse_domain_destroy(dev->domain[j]);
> >
> > Why not move the above error handling to the err label?
> >
>
> That implies I need to signal the index of successfully created
> domains. We only need to handle that in this part of the code. To move
> it is not impossible of course but it complicates the code IMO. I'd be
> happy to move it if requested though.
>
> > > + goto err_domain;
> > > + }
> > > + }
> > > +
> > > mutex_unlock(&dev->domain_lock);
> > > - if (!dev->domain) {
> > > + if (ret == -ENOMEM) {
> > > put_device(&dev->vdev->vdpa.dev);
> > > return -ENOMEM;
> > > }
> > > @@ -2150,13 +2276,22 @@ static int vdpa_dev_add(struct vdpa_mgmt_dev *mdev, const char *name,
> > > if (ret) {
> > > put_device(&dev->vdev->vdpa.dev);
> > > mutex_lock(&dev->domain_lock);
> > > - vduse_domain_destroy(dev->domain);
> > > - dev->domain = NULL;
> > > + for (int i = 0; i < dev->nas; i++) {
> > > + if (dev->domain[i]) {
> > > + vduse_domain_destroy(dev->domain[i]);
> > > + dev->domain[i] = NULL;
> > > + }
> > > + }
> > > mutex_unlock(&dev->domain_lock);
> > > return ret;
> > > }
> > >
> > > return 0;
> > > +
> > > +err_domain:
> > > + /* TODO do I need to call put_device? */
> >
> > If it comes after the success of vduse_dev_init_vdpa().
> >
>
> Ouch, that was a TODO for me but I forgot to remove it, sorry :).
>
> > > + mutex_unlock(&dev->domain_lock);
> > > + return ret;
> > > }
> > >
> > > static void vdpa_dev_del(struct vdpa_mgmt_dev *mdev, struct vdpa_device *dev)
> > > diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> > > index b4b139dc76bb..d300fd5f867f 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[];
> > > };
> > > @@ -82,6 +83,17 @@ struct vduse_iotlb_entry {
> > > __u8 perm;
> > > };
> > >
> > > +struct vduse_iotlb_entry_v2 {
> > > + __u64 offset;
> > > + __u64 start;
> > > + __u64 last;
> > > +#define VDUSE_ACCESS_RO 0x1
> > > +#define VDUSE_ACCESS_WO 0x2
> > > +#define VDUSE_ACCESS_RW 0x3
> > > + __u8 perm;
> >
> > We can embed vduse_iotlb_entry here. This will ease the userspace development.
> >
>
> I agree, I'll do it that way for the next version.
>
> > > + __u32 asid;
> > > +};
> > > +
> > > /*
> > > * Find the first IOVA region that overlaps with the range [start, last]
> > > * and return the corresponding file descriptor. Return -EINVAL means the
> > > @@ -172,6 +184,16 @@ struct vduse_vq_group {
> > > __u32 num;
> > > };
> > >
> > > +/**
> > > + * struct vduse_vq_group - virtqueue group
> > > + @ @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
> > > @@ -232,6 +254,7 @@ 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
> > > @@ -241,7 +264,8 @@ struct vduse_iova_umem {
> > > __u64 uaddr;
> > > __u64 iova;
> > > __u64 size;
> > > - __u64 reserved[3];
> > > + __u32 asid;
> > > + __u32 reserved[5];
> > > };
> > >
> > > /* Register userspace memory for IOVA regions */
> > > @@ -265,7 +289,8 @@ 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];
> > > };
> > >
> > > /*
> > > @@ -289,6 +314,7 @@ enum vduse_req_type {
> > > VDUSE_UPDATE_IOTLB,
> > > VDUSE_GET_VQ_GROUP,
> > > VDUSE_GET_VRING_DESC_GROUP,
> > > + VDUSE_SET_VQ_GROUP_ASID,
> > > };
> > >
> > > /**
> > > @@ -344,6 +370,8 @@ struct vduse_dev_request {
> > > struct vduse_dev_status s;
> > > struct vduse_iova_range iova;
> > > struct vduse_vq_group vq_group; /* Only if vduse api version >= 1 */
> > > + /* Only if vduse api version >= 1 */
> >
> > We can use:
> >
> > /* Only if vduse api version >= 1 */
> > struct vduse_vq_group vq_group;
> > struct vduse_vq_group_asid vq_group_asid;
> >
>
> I'm happy to do it that way, but it is not clear to me that both
> members are only if version >=1. Maybe "The following members are
> valid only if..."?
>
> > > + struct vduse_vq_group_asid vq_group_asid;
> > > __u32 padding[32];
> > > };
> > > };
> > > @@ -367,6 +395,8 @@ struct vduse_dev_response {
> > > union {
> > > struct vduse_vq_state vq_state;
> > > struct vduse_vq_group vq_group; /* Only if vduse api version >= 1 */
> > > + /* Only if vduse api version >= 1 */
> > > + struct vduse_vq_group_asid vq_group_asid;
> > > __u32 padding[32];
> > > };
> > > };
> > > --
> > > 2.50.1
> > >
> >
> > Thanks
> >
>
Thanks
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