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SubjectRe: [RFC PATCH 18/24] vhost-vdpa: support ASID based IOTLB API
On Thu, Sep 24, 2020 at 5:25 AM Jason Wang <jasowang@redhat.com> wrote:
>
> This patch extends the vhost-vdpa to support ASID based IOTLB API. The
> vhost-vdpa device will allocated multple IOTLBs for vDPA device that
> supports multiple address spaces. The IOTLBs and vDPA device memory
> mappings is determined and maintained through ASID.
>
> Note that we still don't support vDPA device with more than one
> address spaces that depends on platform IOMMU. This work will be done
> by moving the IOMMU logic from vhost-vDPA to vDPA device driver.
>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> drivers/vhost/vdpa.c | 106 ++++++++++++++++++++++++++++++++-----------
> 1 file changed, 79 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 978cf97dc03a..99ac13b2ed11 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -29,7 +29,8 @@
> enum {
> VHOST_VDPA_BACKEND_FEATURES =
> (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) |
> - (1ULL << VHOST_BACKEND_F_IOTLB_BATCH),
> + (1ULL << VHOST_BACKEND_F_IOTLB_BATCH) |
> + (1ULL << VHOST_BACKEND_F_IOTLB_ASID),
> };
>
> #define VHOST_VDPA_DEV_MAX (1U << MINORBITS)
> @@ -58,12 +59,20 @@ struct vhost_vdpa {
> struct eventfd_ctx *config_ctx;
> int in_batch;
> int used_as;
> + u32 batch_asid;
> };
>
> static DEFINE_IDA(vhost_vdpa_ida);
>
> static dev_t vhost_vdpa_major;
>
> +static inline u32 iotlb_to_asid(struct vhost_iotlb *iotlb)
> +{
> + struct vhost_vdpa_as *as = container_of(iotlb, struct
> + vhost_vdpa_as, iotlb);
> + return as->id;
> +}
> +
> static struct vhost_vdpa_as *asid_to_as(struct vhost_vdpa *v, u32 asid)
> {
> struct hlist_head *head = &v->as[asid % VHOST_VDPA_IOTLB_BUCKETS];
> @@ -76,6 +85,16 @@ static struct vhost_vdpa_as *asid_to_as(struct vhost_vdpa *v, u32 asid)
> return NULL;
> }
>
> +static struct vhost_iotlb *asid_to_iotlb(struct vhost_vdpa *v, u32 asid)
> +{
> + struct vhost_vdpa_as *as = asid_to_as(v, asid);
> +
> + if (!as)
> + return NULL;
> +
> + return &as->iotlb;
> +}
> +
> static struct vhost_vdpa_as *vhost_vdpa_alloc_as(struct vhost_vdpa *v, u32 asid)
> {
> struct hlist_head *head = &v->as[asid % VHOST_VDPA_IOTLB_BUCKETS];
> @@ -84,6 +103,9 @@ static struct vhost_vdpa_as *vhost_vdpa_alloc_as(struct vhost_vdpa *v, u32 asid)
> if (asid_to_as(v, asid))
> return NULL;
>
> + if (asid >= v->vdpa->nas)
> + return NULL;
> +
> as = kmalloc(sizeof(*as), GFP_KERNEL);
> if (!as)
> return NULL;
> @@ -96,13 +118,20 @@ static struct vhost_vdpa_as *vhost_vdpa_alloc_as(struct vhost_vdpa *v, u32 asid)
> return as;
> }
>
> -static int vhost_vdpa_remove_as(struct vhost_vdpa *v, u32 asid)
> +static struct vhost_vdpa_as *vhost_vdpa_find_alloc_as(struct vhost_vdpa *v,
> + u32 asid)
> {
> struct vhost_vdpa_as *as = asid_to_as(v, asid);
>
> - /* Remove default address space is not allowed */
> - if (asid == 0)
> - return -EINVAL;
> + if (as)
> + return as;
> +
> + return vhost_vdpa_alloc_as(v, asid);
> +}
> +
> +static int vhost_vdpa_remove_as(struct vhost_vdpa *v, u32 asid)
> +{
> + struct vhost_vdpa_as *as = asid_to_as(v, asid);
>
> if (!as)
> return -EINVAL;
> @@ -623,6 +652,7 @@ static int vhost_vdpa_map(struct vhost_vdpa *v, struct vhost_iotlb *iotlb,
> {
> struct vdpa_device *vdpa = v->vdpa;
> const struct vdpa_config_ops *ops = vdpa->config;
> + u32 asid = iotlb_to_asid(iotlb);
> int r = 0;
>
> r = vhost_iotlb_add_range(iotlb, iova, iova + size - 1,
> @@ -631,10 +661,10 @@ static int vhost_vdpa_map(struct vhost_vdpa *v, struct vhost_iotlb *iotlb,
> return r;
>
> if (ops->dma_map) {
> - r = ops->dma_map(vdpa, 0, iova, size, pa, perm);
> + r = ops->dma_map(vdpa, asid, iova, size, pa, perm);
> } else if (ops->set_map) {
> if (!v->in_batch)
> - r = ops->set_map(vdpa, 0, iotlb);
> + r = ops->set_map(vdpa, asid, iotlb);
> } else {
> r = iommu_map(v->domain, iova, pa, size,
> perm_to_iommu_flags(perm));
> @@ -643,23 +673,32 @@ static int vhost_vdpa_map(struct vhost_vdpa *v, struct vhost_iotlb *iotlb,
> return r;
> }
>
> -static void vhost_vdpa_unmap(struct vhost_vdpa *v,
> - struct vhost_iotlb *iotlb,
> - u64 iova, u64 size)
> +static int vhost_vdpa_unmap(struct vhost_vdpa *v,
> + struct vhost_iotlb *iotlb,
> + u64 iova, u64 size)
> {
> struct vdpa_device *vdpa = v->vdpa;
> const struct vdpa_config_ops *ops = vdpa->config;
> + u32 asid = (iotlb);
> +
> + if (!iotlb)
> + return -EINVAL;

This should be reorder to check for (!iotlb) before use at `asid =
iotlb_to_asid()`, isn't it?

Thanks!

>
> vhost_vdpa_iotlb_unmap(v, iotlb, iova, iova + size - 1);
>
> if (ops->dma_map) {
> - ops->dma_unmap(vdpa, 0, iova, size);
> + ops->dma_unmap(vdpa, asid, iova, size);
> } else if (ops->set_map) {
> if (!v->in_batch)
> - ops->set_map(vdpa, 0, iotlb);
> + ops->set_map(vdpa, asid, iotlb);
> } else {
> iommu_unmap(v->domain, iova, size);
> }
> +
> + if (!iotlb->nmaps)
> + vhost_vdpa_remove_as(v, asid);
> +
> + return 0;
> }
>
> static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
> @@ -755,30 +794,38 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev, u32 asid,
> struct vhost_vdpa *v = container_of(dev, struct vhost_vdpa, vdev);
> struct vdpa_device *vdpa = v->vdpa;
> const struct vdpa_config_ops *ops = vdpa->config;
> - struct vhost_vdpa_as *as = asid_to_as(v, 0);
> - struct vhost_iotlb *iotlb = &as->iotlb;
> + struct vhost_iotlb *iotlb = asid_to_iotlb(v, asid);
> + struct vhost_vdpa_as *as;
> int r = 0;
>
> - if (asid != 0)
> - return -EINVAL;
> -
> r = vhost_dev_check_owner(dev);
> if (r)
> return r;
>
> + if ((msg->type == VHOST_IOTLB_UPDATE) && !iotlb) {
> + as = vhost_vdpa_find_alloc_as(v, asid);
> + if (!as)
> + return -EINVAL;
> + iotlb = &as->iotlb;
> + }
> +
> + if (v->in_batch && v->batch_asid != asid)
> + return -EINVAL;
> +
> switch (msg->type) {
> case VHOST_IOTLB_UPDATE:
> r = vhost_vdpa_process_iotlb_update(v, iotlb, msg);
> break;
> case VHOST_IOTLB_INVALIDATE:
> - vhost_vdpa_unmap(v, iotlb, msg->iova, msg->size);
> + r = vhost_vdpa_unmap(v, iotlb, msg->iova, msg->size);
> break;
> case VHOST_IOTLB_BATCH_BEGIN:
> + v->batch_asid = asid;
> v->in_batch = true;
> break;
> case VHOST_IOTLB_BATCH_END:
> if (v->in_batch && ops->set_map)
> - ops->set_map(vdpa, 0, iotlb);
> + ops->set_map(vdpa, asid, iotlb);
> v->in_batch = false;
> break;
> default:
> @@ -848,9 +895,17 @@ static void vhost_vdpa_free_domain(struct vhost_vdpa *v)
>
> static void vhost_vdpa_cleanup(struct vhost_vdpa *v)
> {
> + struct vhost_vdpa_as *as;
> + u32 asid;
> +
> vhost_dev_cleanup(&v->vdev);
> kfree(v->vdev.vqs);
> - vhost_vdpa_remove_as(v, 0);
> +
> + for (asid = 0; asid < v->vdpa->nas; asid++) {
> + as = asid_to_as(v, asid);
> + if (as)
> + vhost_vdpa_remove_as(v, asid);
> + }
> }
>
> static int vhost_vdpa_open(struct inode *inode, struct file *filep)
> @@ -883,18 +938,15 @@ static int vhost_vdpa_open(struct inode *inode, struct file *filep)
> vhost_dev_init(dev, vqs, nvqs, 0, 0, 0, false,
> vhost_vdpa_process_iotlb_msg);
>
> - if (!vhost_vdpa_alloc_as(v, 0))
> - goto err_alloc_as;
> -
> r = vhost_vdpa_alloc_domain(v);
> if (r)
> - goto err_alloc_as;
> + goto err_alloc_domain;
>
> filep->private_data = v;
>
> return 0;
>
> -err_alloc_as:
> +err_alloc_domain:
> vhost_vdpa_cleanup(v);
> err:
> atomic_dec(&v->opened);
> @@ -1022,8 +1074,8 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
> int minor;
> int i, r;
>
> - /* Only support 1 address space */
> - if (vdpa->ngroups != 1)
> + /* We can't support platform IOMMU device with more than 1 group */
> + if (!ops->set_map && !ops->dma_map && vdpa->ngroups > 1)
> return -ENOTSUPP;
>
> /* Currently, we only accept the network devices. */
> --
> 2.20.1
>

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