[PATCH V2 2/3] vhost: vdpa: report iova range

Jason Wang
2020-08-21T09:28:46Z

This patch introduces a new ioctl for vhost-vdpa device that can
report the iova range by the device.

For device that implements get_iova_range() method, we fetch it from
the vDPA device. If device doesn't implement get_iova_range() but
depends on platform IOMMU, we will query via DOMAIN_ATTR_GEOMETRY,
otherwise [0, ULLONG_MAX] is assumed.

For safety, this patch also rules out the map request which is not in
the valid range.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/vdpa.c | 41 ++++++++++++++++++++++++++++++++
include/uapi/linux/vhost.h | 4 ++++
include/uapi/linux/vhost_types.h | 9 +++++++
3 files changed, 54 insertions(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 3fab94f88894..1adb4adb0345 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -48,6 +48,7 @@ struct vhost_vdpa {
int minor;
struct eventfd_ctx *config_ctx;
int in_batch;
+ struct vdpa_iova_range range;
};

static DEFINE_IDA(vhost_vdpa_ida);
@@ -344,6 +345,16 @@ static long vhost_vdpa_set_config_call(struct vhost_vdpa *v, u32 __user *argp)
return 0;
}

+static long vhost_vdpa_get_iova_range(struct vhost_vdpa *v, u32 __user *argp)
+{
+ struct vhost_vdpa_iova_range range = {
+ .first = v->range.first,
+ .last = v->range.last,
+ };
+
+ return copy_to_user(argp, &range, sizeof(range));
+}
+
static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
void __user *argp)
{
@@ -476,6 +487,9 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
case VHOST_VDPA_SET_CONFIG_CALL:
r = vhost_vdpa_set_config_call(v, argp);
break;
+ case VHOST_VDPA_GET_IOVA_RANGE:
+ r = vhost_vdpa_get_iova_range(v, argp);
+ break;
default:
r = vhost_dev_ioctl(&v->vdev, cmd, argp);
if (r == -ENOIOCTLCMD)
@@ -597,6 +611,10 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
u64 iova = msg->iova;
int ret = 0;

+ if (msg->iova < v->range.first ||
+ msg->iova + msg->size - 1 > v->range.last)
+ return -EINVAL;
+
if (vhost_iotlb_itree_first(iotlb, msg->iova,
msg->iova + msg->size - 1))
return -EEXIST;
@@ -762,6 +780,27 @@ static void vhost_vdpa_free_domain(struct vhost_vdpa *v)
v->domain = NULL;
}

+static void vhost_vdpa_set_iova_range(struct vhost_vdpa *v)
+{
+ struct vdpa_iova_range *range = &v->range;
+ struct iommu_domain_geometry geo;
+ struct vdpa_device *vdpa = v->vdpa;
+ const struct vdpa_config_ops *ops = vdpa->config;
+
+ if (ops->get_iova_range) {
+ *range = ops->get_iova_range(vdpa);
+ } else if (v->domain &&
+ !iommu_domain_get_attr(v->domain,
+ DOMAIN_ATTR_GEOMETRY, &geo) &&
+ geo.force_aperture) {
+ range->first = geo.aperture_start;
+ range->last = geo.aperture_end;
+ } else {
+ range->first = 0;
+ range->last = ULLONG_MAX;
+ }
+}
+
static int vhost_vdpa_open(struct inode *inode, struct file *filep)
{
struct vhost_vdpa *v;
@@ -802,6 +841,8 @@ static int vhost_vdpa_open(struct inode *inode, struct file *filep)
if (r)
goto err_init_iotlb;

+ vhost_vdpa_set_iova_range(v);
+
filep->private_data = v;

return 0;
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index 75232185324a..c998860d7bbc 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -146,4 +146,8 @@

/* Set event fd for config interrupt*/
#define VHOST_VDPA_SET_CONFIG_CALL _IOW(VHOST_VIRTIO, 0x77, int)
+
+/* Get the valid iova range */
+#define VHOST_VDPA_GET_IOVA_RANGE _IOR(VHOST_VIRTIO, 0x78, \
+ struct vhost_vdpa_iova_range)
#endif
diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h
index 9a269a88a6ff..f7f6a3a28977 100644
--- a/include/uapi/linux/vhost_types.h
+++ b/include/uapi/linux/vhost_types.h
@@ -138,6 +138,15 @@ struct vhost_vdpa_config {
__u8 buf[0];
};

+/* vhost vdpa IOVA range
+ * @first: First address that can be mapped by vhost-vDPA
+ * @last: Last address that can be mapped by vhost-vDPA
+ */
+struct vhost_vdpa_iova_range {
+ __u64 first;
+ __u64 last;
+};
+
/* Feature bits */
/* Log all write descriptors. Can be changed while device is active. */
#define VHOST_F_LOG_ALL 26
--
2.18.1