[RFC PATCH V3 4/5] vhost: introduce helpers to get the size of metadata area

Jason Wang
2018-12-29T12:46:55Z

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/vhost.c | 46 ++++++++++++++++++++++++++-----------------
1 file changed, 28 insertions(+), 18 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 27b5c03feaac..54b43feef8d9 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -489,6 +489,27 @@ bool vhost_dev_has_owner(struct vhost_dev *dev)
}
EXPORT_SYMBOL_GPL(vhost_dev_has_owner);

+static size_t vhost_get_avail_size(struct vhost_virtqueue *vq, int num)
+{
+ size_t event = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
+
+ return sizeof(*vq->avail) +
+ sizeof(*vq->avail->ring) * num + event;
+}
+
+static size_t vhost_get_used_size(struct vhost_virtqueue *vq, int num)
+{
+ size_t event = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
+
+ return sizeof(*vq->used) +
+ sizeof(*vq->used->ring) * num + event;
+}
+
+static size_t vhost_get_desc_size(struct vhost_virtqueue *vq, int num)
+{
+ return sizeof(*vq->desc) * num;
+}
+
/* Caller should have device mutex */
long vhost_dev_set_owner(struct vhost_dev *dev)
{
@@ -1248,13 +1269,9 @@ static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
struct vring_used __user *used)

{
- size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
-
- return access_ok(VERIFY_READ, desc, num * sizeof *desc) &&
- access_ok(VERIFY_READ, avail,
- sizeof *avail + num * sizeof *avail->ring + s) &&
- access_ok(VERIFY_WRITE, used,
- sizeof *used + num * sizeof *used->ring + s);
+ return access_ok(VERIFY_READ, desc, vhost_get_desc_size(vq, num)) &&
+ access_ok(VERIFY_READ, avail, vhost_get_avail_size(vq, num)) &&
+ access_ok(VERIFY_WRITE, used, vhost_get_used_size(vq, num));
}

static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
@@ -1306,22 +1323,18 @@ static bool iotlb_access_ok(struct vhost_virtqueue *vq,

int vq_meta_prefetch(struct vhost_virtqueue *vq)
{
- size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
unsigned int num = vq->num;

if (!vq->iotlb)
return 1;

return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
- num * sizeof(*vq->desc), VHOST_ADDR_DESC) &&
+ vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) &&
iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail,
- sizeof *vq->avail +
- num * sizeof(*vq->avail->ring) + s,
+ vhost_get_avail_size(vq, num),
VHOST_ADDR_AVAIL) &&
iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used,
- sizeof *vq->used +
- num * sizeof(*vq->used->ring) + s,
- VHOST_ADDR_USED);
+ vhost_get_used_size(vq, num), VHOST_ADDR_USED);
}
EXPORT_SYMBOL_GPL(vq_meta_prefetch);

@@ -1338,13 +1351,10 @@ EXPORT_SYMBOL_GPL(vhost_log_access_ok);
static bool vq_log_access_ok(struct vhost_virtqueue *vq,
void __user *log_base)
{
- size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
-
return vq_memory_access_ok(log_base, vq->umem,
vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
(!vq->log_used || log_access_ok(log_base, vq->log_addr,
- sizeof *vq->used +
- vq->num * sizeof *vq->used->ring + s));
+ vhost_get_used_size(vq, vq->num)));
}

/* Can we start vq? */
--
2.17.1