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Message-ID: <CAJaqyWf95h_amybhC3eR_LFPweAt_zoO6_rc=Mw=kP9OmujA2g@mail.gmail.com>
Date: Thu, 7 Aug 2025 13:10:51 +0200
From: Eugenio Perez Martin <eperezma@...hat.com>
To: Jason Wang <jasowang@...hat.com>
Cc: Yongji Xie <xieyongji@...edance.com>, Cindy Lu <lulu@...hat.com>,
linux-kernel@...r.kernel.org, Stefano Garzarella <sgarzare@...hat.com>,
Stefan Hajnoczi <stefanha@...hat.com>, Maxime Coquelin <mcoqueli@...hat.com>,
"Michael S. Tsirkin" <mst@...hat.com>, virtualization@...ts.linux.dev,
Xuan Zhuo <xuanzhuo@...ux.alibaba.com>, Laurent Vivier <lvivier@...hat.com>
Subject: Re: [RFC 3/6] vduse: add vq group asid support
On Fri, Jun 13, 2025 at 3:21 AM Jason Wang <jasowang@...hat.com> wrote:
>
> On Thu, Jun 12, 2025 at 3:25 PM Eugenio Perez Martin
> <eperezma@...hat.com> wrote:
> >
> > On Thu, Jun 12, 2025 at 2:30 AM Jason Wang <jasowang@...hat.com> wrote:
> > >
> > > On Fri, Jun 6, 2025 at 7:50 PM Eugenio Pérez <eperezma@...hat.com> wrote:
> > > >
> > > > Make one IOTLB domain per address space, and allow the driver to assign
> > > > each ASID to a vq group. Each address space via an dedicated identifier
> > > > (ASID).
> > > >
> > > > During vDPA device allocation, the VDUSE device needs to report the
> > > > number of address spaces supported. Then the vdpa driver is able to
> > > > configure them. At this moment only vhost_vdpa is able to do it.
> > > >
> > > > This helps to isolate the environments for the virtqueue that will not
> > > > be assigned directly. E.g in the case of virtio-net, the control
> > > > virtqueue will not be assigned directly to guest.
> > > >
> > > > TODO: Ideally, umem should not be duplicated. But it is hard or
> > > > impossible to refactor everything around one single umem. So should we
> > > > continue with device specifying umem per vq group?
> > >
> > > This is a good question.
> > >
> > > I think umem should be bound to address space and umem needs to be isolated.
> > >
> > > For the issue of complexity, we can simply extend the vduse_iova_umem
> > > to have an asid field. But it looks like it needs more work as:
> > >
> > > struct vduse_iova_umem {
> > > __u64 uaddr;
> > > __u64 iova;
> > > __u64 size;
> > > __u64 reserved[3];
> > > };
> > >
> > > Do we have a way to know if reserved is used or not (as we are lacking
> > > a flag field anyhow ....).
> > >
> >
> > I'd say that we should work the same way as the rest of the structs:
> > We add the asid field, and if the API v1 is negotiated we handle it as
> > ASID. If it is not negotiated, it is reserved.
>
> Ok, that makes sense.
>
> >
> > > So we probably need a new uAPI like vduse_iova_umem_v2 that includes a
> > > flag field at least.
> > >
> > > >
> > > > Signed-off-by: Eugenio Pérez <eperezma@...hat.com>
> > > > ---
> > > > drivers/vdpa/vdpa_user/vduse_dev.c | 250 +++++++++++++++++++++--------
> > > > include/uapi/linux/vduse.h | 38 ++++-
> > > > 2 files changed, 216 insertions(+), 72 deletions(-)
> > > >
> > > > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> > > > index 6fa687bc4912..d51e4f26fe72 100644
> > > > --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> > > > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> > > > @@ -51,6 +51,11 @@
> > > > */
> > > > #define VDUSE_MAX_VQ_GROUPS 2
> > > >
> > > > +/*
> > > > + * Let's make it 2 for simplicity.
> > > > + */
> > > > +#define VDUSE_MAX_ASID 2
> > >
> > > Similar to previous patch, it's better to increase this otherwise we
> > > need new uAPI or it requires the userspace to probe the maximum value
> > > once we decide to change it in the future.
> > >
> >
> > I'm ok with this, but what is a good max value? UINT32_MAX seems excessive?
>
> Maybe 64 or 256.
>
> >
> > This requires us to allocate arrays for both vduse_dev->domain and
> > vduse_dev->umem, so we need to set a reasonable value.
>
> Could we do the allocation based on the userspace privionsing?
>
Oh yes, my point is that we need to set a hard maximum so userland
cannot allocate an array of uint32_t[UINT32_MAX], for example. I guess
64 is reasonable. Is it worth it to dynamically allocate a whole array
with this maximum or is it better to make it just part of the struct?
I'm happy with both solutions :).
> >
> > > > +
> > > > #define IRQ_UNBOUND -1
> > > >
> > > > struct vduse_virtqueue {
> > > > @@ -92,7 +97,7 @@ 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;
> > > > @@ -120,7 +125,8 @@ 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 mutex mem_lock;
> > > > unsigned int bounce_size;
> > > > struct mutex domain_lock;
> > > > @@ -436,11 +442,14 @@ 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->domain[i];
> > > > +
> > > > + if (domain && domain->bounce_map)
> > > > + vduse_domain_reset_bounce_map(domain);
> > > > + }
> > > >
> > > > down_write(&dev->rwsem);
> > > >
> > > > @@ -617,6 +626,23 @@ static u32 vduse_get_vq_group(struct vdpa_device *vdpa, u16 idx)
> > > > return msg.resp.vq_group.num;
> > > > }
> > > >
> > > > +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 };
> > > > +
> > > > + 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;
> > > > +
> > > > + return vduse_dev_msg_sync(dev, &msg);
> > > > +}
> > > > +
> > > > static int vduse_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 idx,
> > > > struct vdpa_vq_state *state)
> > > > {
> > > > @@ -788,13 +814,13 @@ 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;
> > > > }
> > > >
> > > > @@ -837,6 +863,7 @@ 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,
> > > > .free = vduse_vdpa_free,
> > > > };
> > > >
> > > > @@ -845,9 +872,12 @@ static void vduse_dev_sync_single_for_device(struct device *dev,
> > > > enum dma_data_direction dir)
> > > > {
> > > > struct vduse_dev *vdev = dev_to_vduse(dev);
> > > > - struct vduse_iova_domain *domain = vdev->domain;
> > > >
> > > > - vduse_domain_sync_single_for_device(domain, dma_addr, size, dir);
> > > > + for (int i = 0; i < vdev->nas; i++) {
> > > > + struct vduse_iova_domain *domain = vdev->domain[i];
> > >
> > > Interesting, I thought there could be a way to deduce the iova domain
> > > from the dma device since virtio supports per virtqueue dma device
> > > now. For example, I don't see get_vq_dma_dev() implemented in this
> > > patch.
> >
> > vhost_vdpa does not interact with it so it was not needed for the RFC.
> > For example, the simulator does not implement it either and it works
> > with ASID.
>
> Right, the reason for it is:
>
> 1) in vdpasim_create() we assign vdpa device as the device device:
>
> vdpasim->vdpa.dma_dev = dev;
>
> 2) since the vDPA device itself can't do DMA, it tricks the DMA ops to use a PA
> 3) we do 1:1 mapping in vringh IOTLB by default to make the PA trick work:
>
> vhost_iotlb_add_range(&vdpasim->iommu[i], 0, ULONG_MAX, 0,
> VHOST_MAP_RW);
>
> 4) This trick works the case oneday virtio_vdpa may use
> set_group_asid() as well, as all the AS are using PA
>
> Note that it's 2) that is blamed by the DMA maintainer.
>
> It looks different from VDUSE here:
>
> 1) VDUSE has its own dma_ops, each as is backed by different IOVA
> domain as well as IOVA address
> 2) vduse_domain_sync_single_for_device() will trigger unnecessary
> IOTLB synchronizations
>
> >
> > > But anyhow maybe we need to revisit this point as DMA
> > > mainatiner ask to fix the abuse of the dma device so we don't need a
> > > trick for dma dev anymore if we design the new mapping API in virtio
> > > core correctly.
> > >
> > > > +
> > > > + vduse_domain_sync_single_for_device(domain, dma_addr, size, dir);
> > > > + }
> > > > }
> > > >
> > > > static void vduse_dev_sync_single_for_cpu(struct device *dev,
> > > > @@ -855,9 +885,12 @@ static void vduse_dev_sync_single_for_cpu(struct device *dev,
> > > > enum dma_data_direction dir)
> > > > {
> > > > struct vduse_dev *vdev = dev_to_vduse(dev);
> > > > - struct vduse_iova_domain *domain = vdev->domain;
> > > >
> > > > - vduse_domain_sync_single_for_cpu(domain, dma_addr, size, dir);
> > > > + for (int i = 0; i < vdev->nas; i++) {
> > > > + struct vduse_iova_domain *domain = vdev->domain[i];
> > > > +
> > > > + vduse_domain_sync_single_for_cpu(domain, dma_addr, size, dir);
> > > > + }
> > > > }
> > > >
> > > > static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,
> > > > @@ -866,7 +899,7 @@ static dma_addr_t vduse_dev_map_page(struct device *dev, struct page *page,
> > > > unsigned long attrs)
> > > > {
> > > > struct vduse_dev *vdev = dev_to_vduse(dev);
> > > > - struct vduse_iova_domain *domain = vdev->domain;
> > > > + struct vduse_iova_domain *domain = vdev->domain[0];
> > >
> > > Any reason that we need to assume asid 0 in this case?
> > >
> >
> > At this moment, virtio_vdpa is the only one using these functions and
> > it is not able to change ASID. So this must be 0 for the moment. But
> > yes, this should be better addressed by knowing what vq group is this
> > referring to.
>
> My plan is to
>
> 1) introduce map_ops() in the virtio_device()
> 2) in PCI, it will be converted to DMA ops
> 3) for vDPA, it will be converted to vDPA specific ops
> 4) get_vq_dma_dev() will be converted to get_vq_map_token(), so each
> vq could provide it's own token
> 5) when the virtio core tries to do mapping, it will pass per vq dma
> token as parameters
> 6) so vduse here can receive a per virtqueue token where it can map it
> to group then ASID
>
> >
> > > >
> > > > return vduse_domain_map_page(domain, page, offset, size, dir, attrs);
> > > > }
> > > > @@ -876,7 +909,7 @@ static void vduse_dev_unmap_page(struct device *dev, dma_addr_t dma_addr,
> > > > unsigned long attrs)
> > > > {
> > > > struct vduse_dev *vdev = dev_to_vduse(dev);
> > > > - struct vduse_iova_domain *domain = vdev->domain;
> > > > + struct vduse_iova_domain *domain = vdev->domain[0];
> > > >
> > > > return vduse_domain_unmap_page(domain, dma_addr, size, dir, attrs);
> > > > }
> > > > @@ -886,7 +919,7 @@ static void *vduse_dev_alloc_coherent(struct device *dev, size_t size,
> > > > unsigned long attrs)
> > > > {
> > > > struct vduse_dev *vdev = dev_to_vduse(dev);
> > > > - struct vduse_iova_domain *domain = vdev->domain;
> > > > + struct vduse_iova_domain *domain = vdev->domain[0];
> > > > unsigned long iova;
> > > > void *addr;
> > > >
> > > > @@ -906,17 +939,25 @@ static void vduse_dev_free_coherent(struct device *dev, size_t size,
> > > > unsigned long attrs)
> > > > {
> > > > struct vduse_dev *vdev = dev_to_vduse(dev);
> > > > - struct vduse_iova_domain *domain = vdev->domain;
> > > > + struct vduse_iova_domain *domain = vdev->domain[0];
> > > >
> > > > vduse_domain_free_coherent(domain, size, vaddr, dma_addr, attrs);
> > > > }
> > > >
> > > > +/* TODO check if this is correct */
> > > > static size_t vduse_dev_max_mapping_size(struct device *dev)
> > > > {
> > > > struct vduse_dev *vdev = dev_to_vduse(dev);
> > > > - struct vduse_iova_domain *domain = vdev->domain;
> > > > + size_t max_mapping_size = 0;
> > > > +
> > > > + for (int i = 0; i < vdev->nas; i++) {
> > > > + struct vduse_iova_domain *domain = vdev->domain[i];
> > > >
> > > > - return domain->bounce_size;
> > > > + if (domain->bounce_size > max_mapping_size)
> > > > + max_mapping_size = domain->bounce_size;
> > > > + }
> > > > +
> > > > + return max_mapping_size;
> > > > }
> > > >
> > > > static const struct dma_map_ops vduse_dev_dma_ops = {
> > > > @@ -1054,31 +1095,32 @@ 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);
> > > > @@ -1086,7 +1128,7 @@ 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;
> > > > @@ -1094,14 +1136,14 @@ 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;
> > > > @@ -1125,7 +1167,7 @@ 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;
> > > > @@ -1138,7 +1180,7 @@ 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);
> > > > @@ -1181,26 +1223,42 @@ 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.perm = entry_old.perm;
> > >
> > > I wonder if a new ioctl is needed.
> > >
> >
> > The problem is that vduse_iotlb_entry is already used in full, can we
> > extend the argument size without introducing the new ioctl?
>
> Yes, I think it should work if VDUSE_API_VERSION_1 makes sense.
>
> >
> > > > + }
> > > >
> > > > 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;
> > > > @@ -1210,7 +1268,7 @@ 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)
> > > > @@ -1360,12 +1418,18 @@ 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)) ||
> > > > + !is_mem_zero((const char *)umem.reserved2,
> > > > + sizeof(umem.reserved2)) ||
> > > > + (dev->api_version < VDUSE_API_VERSION_1 &&
> > > > + umem.asid != 0) ||
> > > > + umem.asid >= dev->nas)
> > >
> > > This is probably a hint that we need a new uAPI, see my comment for changelog.
> > >
> > > > 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;
> > > > @@ -1378,15 +1442,23 @@ 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)) ||
> > > > + !is_mem_zero((const char *)umem.reserved2,
> > > > + sizeof(umem.reserved2)) ||
> > > > + (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,
> > > > + 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? */
> > > > case VDUSE_IOTLB_GET_INFO: {
> > > > struct vduse_iova_info info;
> > > > struct vhost_iotlb_map *map;
> > > > @@ -1399,27 +1471,32 @@ 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? */
> > > > + 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;
> > > > @@ -1444,8 +1521,13 @@ 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 */
> > > > @@ -1715,8 +1797,10 @@ 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);
> > > > vduse_dev_destroy(dev);
> > > > module_put(THIS_MODULE);
> > > > @@ -1824,7 +1908,7 @@ static ssize_t bounce_size_store(struct device *device,
> > > >
> > > > ret = -EPERM;
> > > > mutex_lock(&dev->domain_lock);
> > > > - if (dev->domain)
> > > > + if (dev->domain[0] && dev->domain[1])
> > > > goto unlock;
> > > >
> > > > ret = kstrtouint(buf, 10, &bounce_size);
> > > > @@ -1882,9 +1966,18 @@ static int vduse_create_dev(struct vduse_dev_config *config,
> > > > config->ngroups, VDUSE_MAX_VQ_GROUPS);
> > > > goto err_ngroups;
> > > > }
> > > > +
> > > > + 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;
> > > > }
> > > > dev->name = kstrdup(config->name, GFP_KERNEL);
> > > > if (!dev->name)
> > > > @@ -1923,6 +2016,7 @@ static int vduse_create_dev(struct vduse_dev_config *config,
> > > > kfree(dev->name);
> > > > err_ngroups:
> > > > err_str:
> > > > +err_nas:
> > > > vduse_dev_destroy(dev);
> > > > err:
> > > > return ret;
> > > > @@ -2015,7 +2109,6 @@ 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;
> > > > @@ -2040,17 +2133,15 @@ static struct vduse_mgmt_dev *vduse_mgmt;
> > > > static int vduse_dev_init_vdpa(struct vduse_dev *dev, const char *name)
> > > > {
> > > > struct vduse_vdpa *vdev;
> > > > - __u32 ngroups = 1;
> > > > + __u32 ngroups = dev->ngroups;
> > > > int ret;
> > > >
> > > > if (dev->vdev)
> > > > return -EEXIST;
> > > >
> > > > - if (vdev->dev->api_version >= VDUSE_API_VERSION_1)
> > > > - ngroups = vdev->dev->ngroups;
> > > > -
> > > > + /* TODO do we need to store ngroups and nas? vdpa device already store it for us */
> > > > vdev = vdpa_alloc_device(struct vduse_vdpa, vdpa, dev->dev,
> > > > - &vduse_vdpa_config_ops, ngroups, 1, name,
> > > > + &vduse_vdpa_config_ops, ngroups, dev->nas, name,
> > > > true);
> > > > if (IS_ERR(vdev))
> > > > return PTR_ERR(vdev);
> > > > @@ -2088,11 +2179,23 @@ 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 */
> > > > + 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]);
> > > > + goto err_domain;
> > > > + }
> > > > + }
> > > > +
> > > > mutex_unlock(&dev->domain_lock);
> > > > - if (!dev->domain) {
> > > > + if (ret == -ENOMEM) {
> > > > put_device(&dev->vdev->vdpa.dev);
> > > > return -ENOMEM;
> > > > }
> > > > @@ -2101,13 +2204,22 @@ 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? */
> > > > + 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 a779bcddac58..3a17a0b4e938 100644
> > > > --- a/include/uapi/linux/vduse.h
> > > > +++ b/include/uapi/linux/vduse.h
> > > > @@ -46,7 +46,8 @@ 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[];
> > > > };
> > > > @@ -81,6 +82,17 @@ struct vduse_iotlb_entry {
> > > > __u8 perm;
> > > > };
> > > >
> > > > +struct vduse_iotlb_entry_v2 {
> > > > + __u64 offset;
> > > > + __u64 start;
> > > > + __u64 last;
> > > > + __u32 asid;
> > > > +#define VDUSE_ACCESS_RO 0x1
> > > > +#define VDUSE_ACCESS_WO 0x2
> > > > +#define VDUSE_ACCESS_RW 0x3
> > > > + __u8 perm;
> > > > +};
> > > > +
> > > > /*
> > > > * Find the first IOVA region that overlaps with the range [start, last]
> > > > * and return the corresponding file descriptor. Return -EINVAL means the
> > > > @@ -171,6 +183,16 @@ 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
> > > > @@ -231,7 +253,9 @@ 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
> > > > + * @reserved2: for future use, needs to be initialized to zero
> > > > *
> > > > * Structure used by VDUSE_IOTLB_REG_UMEM and VDUSE_IOTLB_DEREG_UMEM
> > > > * ioctls to register/de-register userspace memory for IOVA regions
> > > > @@ -240,7 +264,9 @@ struct vduse_iova_umem {
> > > > __u64 uaddr;
> > > > __u64 iova;
> > > > __u64 size;
> > > > - __u64 reserved[3];
> > > > + __u32 asid;
> > > > + __u32 reserved[1];
> > >
> > > Basically, I'm not sure we can assume reserved to be zero for API_VERSION == 1.
> > >
> >
> > Why not? The ioctl returns -EINVAL if it is not 0, so either an v0 or
> > v1 ioctl user must set it if it wants the ioctl to return success.
>
> Typo, I mean API_VERSION == 0. It is reserved but the kernel doesn't
> mandate it to be zero. But it doesn't matter probably as it will be
> ruled by API_VERSION as you explain above.
>
The kernel ioctl system does not mandate them to be 0, but
vduse_dev_ioctl checks for it to be 0. If returns -EINVAL in case
they're not.
This patch also checks that asid, previously part of "reserved" keeps
being 0 if VDUSE_API < 1.
> >
> > > > + __u64 reserved2[2];
> > >
> > > Any reasons we can't reuse reserved array?
> > >
> >
> > I don't get this comment, we're reusing it, isn't it? I'm just
> > splitting the u64[3] into u32[1]+u64[2]. Maybe it is more elegant to
> > use an u32[5] or similar?
>
> Yes, I mean reuse the u32 array. (but not a must I guess unless the
> ABI is stable).
>
I'm happy with the u32 array too!
> >
> > > > };
> > > >
> > > > /* Register userspace memory for IOVA regions */
> > > > @@ -264,7 +290,8 @@ struct vduse_iova_info {
> > > > __u64 last;
> > > > #define VDUSE_IOVA_CAP_UMEM (1 << 0)
> > > > __u64 capability;
> > > > - __u64 reserved[3];
> > > > + __u64 asid; /* Only if device API version >= 1 */
> > > > + __u64 reserved[2];
> > >
> > > Same here.
> > >
> > > > };
> > > >
> > > > /*
> > > > @@ -287,6 +314,7 @@ enum vduse_req_type {
> > > > VDUSE_SET_STATUS,
> > > > VDUSE_UPDATE_IOTLB,
> > > > VDUSE_GET_VQ_GROUP,
> > > > + VDUSE_SET_VQ_GROUP_ASID,
> > > > };
> > > >
> > > > /**
> > > > @@ -342,6 +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 */
> > > > + struct vduse_vq_group_asid vq_group_asid;
> > >
> > > This seems to break the uAPI as sizeof(struct vduse_dev_request) changes.
> > >
> >
> > It should not change. vduse_vq_group is 64 bits, smaller than padding
> > which is 32bits*32 = 1024bits. And they're both in the same union.
>
> You're right.
>
> >
> > > > __u32 padding[32];
> > > > };
> > > > };
> > > > @@ -365,6 +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;
> > >
> > > Same here.
> > >
> >
> > Same reply :).
>
> Yes.
>
> >
> > > > __u32 padding[32];
> > > > };
> > > > };
> > > > --
> > > > 2.49.0
> > > >
> > >
> > > Thanks
> > >
> >
>
> Thanks
>
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