vhost-vdpa: introduce asid based IOTLB

This patch converts the vhost-vDPA device to support multiple IOTLBs
tagged via ASID via hlist. This will be used for supporting multiple
address spaces in the following patches.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Gautam Dawar <gdawar@xilinx.com>
Message-Id: <20220330180436.24644-11-gdawar@xilinx.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 174c9e8..cd1bee5 100644 (file)
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -33,13 +33,21 @@ enum {
 
 #define VHOST_VDPA_DEV_MAX (1U << MINORBITS)
 
+#define VHOST_VDPA_IOTLB_BUCKETS 16
+
+struct vhost_vdpa_as {
+       struct hlist_node hash_link;
+       struct vhost_iotlb iotlb;
+       u32 id;
+};
+
 struct vhost_vdpa {
        struct vhost_dev vdev;
        struct iommu_domain *domain;
        struct vhost_virtqueue *vqs;
        struct completion completion;
        struct vdpa_device *vdpa;
-       struct vhost_iotlb *iotlb;
+       struct hlist_head as[VHOST_VDPA_IOTLB_BUCKETS];
        struct device dev;
        struct cdev cdev;
        atomic_t opened;
@@ -55,6 +63,51 @@ static DEFINE_IDA(vhost_vdpa_ida);
 
 static dev_t vhost_vdpa_major;
 
+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];
+       struct vhost_vdpa_as *as;
+
+       hlist_for_each_entry(as, head, hash_link)
+               if (as->id == asid)
+                       return as;
+
+       return NULL;
+}
+
+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];
+       struct vhost_vdpa_as *as;
+
+       if (asid_to_as(v, asid))
+               return NULL;
+
+       as = kmalloc(sizeof(*as), GFP_KERNEL);
+       if (!as)
+               return NULL;
+
+       vhost_iotlb_init(&as->iotlb, 0, 0);
+       as->id = asid;
+       hlist_add_head(&as->hash_link, head);
+
+       return as;
+}
+
+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;
+
+       hlist_del(&as->hash_link);
+       vhost_iotlb_reset(&as->iotlb);
+       kfree(as);
+
+       return 0;
+}
+
 static void handle_vq_kick(struct vhost_work *work)
 {
        struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
@@ -588,15 +641,6 @@ static void vhost_vdpa_iotlb_unmap(struct vhost_vdpa *v,
        return vhost_vdpa_pa_unmap(v, iotlb, start, last);
 }
 
-static void vhost_vdpa_iotlb_free(struct vhost_vdpa *v)
-{
-       struct vhost_iotlb *iotlb = v->iotlb;
-
-       vhost_vdpa_iotlb_unmap(v, iotlb, 0ULL, 0ULL - 1);
-       kfree(v->iotlb);
-       v->iotlb = NULL;
-}
-
 static int perm_to_iommu_flags(u32 perm)
 {
        int flags = 0;
@@ -876,7 +920,8 @@ 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_iotlb *iotlb = v->iotlb;
+       struct vhost_vdpa_as *as = asid_to_as(v, 0);
+       struct vhost_iotlb *iotlb = &as->iotlb;
        int r = 0;
 
        if (asid != 0)
@@ -987,6 +1032,13 @@ static void vhost_vdpa_set_iova_range(struct vhost_vdpa *v)
        }
 }
 
+static void vhost_vdpa_cleanup(struct vhost_vdpa *v)
+{
+       vhost_dev_cleanup(&v->vdev);
+       kfree(v->vdev.vqs);
+       vhost_vdpa_remove_as(v, 0);
+}
+
 static int vhost_vdpa_open(struct inode *inode, struct file *filep)
 {
        struct vhost_vdpa *v;
@@ -1020,15 +1072,12 @@ 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);
 
-       v->iotlb = vhost_iotlb_alloc(0, 0);
-       if (!v->iotlb) {
-               r = -ENOMEM;
-               goto err_init_iotlb;
-       }
+       if (!vhost_vdpa_alloc_as(v, 0))
+               goto err_alloc_as;
 
        r = vhost_vdpa_alloc_domain(v);
        if (r)
-               goto err_alloc_domain;
+               goto err_alloc_as;
 
        vhost_vdpa_set_iova_range(v);
 
@@ -1036,11 +1085,8 @@ static int vhost_vdpa_open(struct inode *inode, struct file *filep)
 
        return 0;
 
-err_alloc_domain:
-       vhost_vdpa_iotlb_free(v);
-err_init_iotlb:
-       vhost_dev_cleanup(&v->vdev);
-       kfree(vqs);
+err_alloc_as:
+       vhost_vdpa_cleanup(v);
 err:
        atomic_dec(&v->opened);
        return r;
@@ -1064,11 +1110,9 @@ static int vhost_vdpa_release(struct inode *inode, struct file *filep)
        vhost_vdpa_clean_irq(v);
        vhost_vdpa_reset(v);
        vhost_dev_stop(&v->vdev);
-       vhost_vdpa_iotlb_free(v);
        vhost_vdpa_free_domain(v);
        vhost_vdpa_config_put(v);
        vhost_dev_cleanup(&v->vdev);
-       kfree(v->vdev.vqs);
        mutex_unlock(&d->mutex);
 
        atomic_dec(&v->opened);
@@ -1164,7 +1208,7 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
        const struct vdpa_config_ops *ops = vdpa->config;
        struct vhost_vdpa *v;
        int minor;
-       int r;
+       int i, r;
 
        /* Only support 1 address space and 1 groups */
        if (vdpa->ngroups != 1 || vdpa->nas != 1)
@@ -1212,6 +1256,9 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
        init_completion(&v->completion);
        vdpa_set_drvdata(vdpa, v);
 
+       for (i = 0; i < VHOST_VDPA_IOTLB_BUCKETS; i++)
+               INIT_HLIST_HEAD(&v->as[i]);
+
        return 0;
 
 err: