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Subject[RFC PATCH 13/24] vhost-vdpa: introduce ASID based IOTLB
Date
This patch introduces the support of ASID based IOTLB by tagging IOTLB
with a unique ASID. This is a must for supporting ASID based vhost
IOTLB API by the following patches.

IOTLB were stored in a hlist and new IOTLB will be allocated when a
new ASID is seen via IOTLB API and destoryed when there's no mapping
associated with an ASID.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/vdpa.c | 94 +++++++++++++++++++++++++++++++++-----------
1 file changed, 72 insertions(+), 22 deletions(-)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 6552987544d7..1ba7e95619b5 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -34,13 +34,21 @@ 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;
@@ -49,12 +57,64 @@ struct vhost_vdpa {
int minor;
struct eventfd_ctx *config_ctx;
int in_batch;
+ int used_as;
};

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);
+ ++v->used_as;
+
+ return as;
+}
+
+static int vhost_vdpa_remove_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 -EINVAL;
+
+ hlist_del(&as->hash_link);
+ vhost_iotlb_reset(&as->iotlb);
+ kfree(as);
+ --v->used_as;
+
+ return 0;
+}
+
static void handle_vq_kick(struct vhost_work *work)
{
struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
@@ -513,15 +573,6 @@ static void vhost_vdpa_iotlb_unmap(struct vhost_vdpa *v,
}
}

-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;
@@ -681,7 +732,8 @@ 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)
@@ -775,6 +827,7 @@ 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)
@@ -807,23 +860,18 @@ 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);

- dev->iotlb = vhost_iotlb_alloc(0, 0);
- if (!dev->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;

filep->private_data = v;

return 0;

-err_alloc_domain:
- vhost_vdpa_iotlb_free(v);
-err_init_iotlb:
+err_alloc_as:
vhost_vdpa_cleanup(v);
err:
atomic_dec(&v->opened);
@@ -851,7 +899,6 @@ static int vhost_vdpa_release(struct inode *inode, struct file *filep)
filep->private_data = NULL;
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_vdpa_clean_irq(v);
@@ -950,7 +997,7 @@ 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 */
if (vdpa->ngroups != 1)
@@ -1002,6 +1049,9 @@ 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:
--
2.20.1
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