[PATCH v6 31/46] vhost: virtio 1.0 endian-ness support

From: Michael S. Tsirkin
Date: Thu Nov 27 2014 - 15:10:53 EST

Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
drivers/vhost/vhost.c | 93 +++++++++++++++++++++++++++++++--------------------
1 file changed, 56 insertions(+), 37 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c90f437..4d379ed 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -33,8 +33,8 @@ enum {
VHOST_MEMORY_F_LOG = 0x1,
};

-#define vhost_used_event(vq) ((u16 __user *)&vq->avail->ring[vq->num])
-#define vhost_avail_event(vq) ((u16 __user *)&vq->used->ring[vq->num])
+#define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num])
+#define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])

static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
poll_table *pt)
@@ -1001,7 +1001,7 @@ EXPORT_SYMBOL_GPL(vhost_log_write);
static int vhost_update_used_flags(struct vhost_virtqueue *vq)
{
void __user *used;
- if (__put_user(vq->used_flags, &vq->used->flags) < 0)
+ if (__put_user(cpu_to_vhost16(vq, vq->used_flags), &vq->used->flags) < 0)
return -EFAULT;
if (unlikely(vq->log_used)) {
/* Make sure the flag is seen before log. */
@@ -1019,7 +1019,7 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq)

static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
{
- if (__put_user(vq->avail_idx, vhost_avail_event(vq)))
+ if (__put_user(cpu_to_vhost16(vq, vq->avail_idx), vhost_avail_event(vq)))
return -EFAULT;
if (unlikely(vq->log_used)) {
void __user *used;
@@ -1038,6 +1038,7 @@ static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)

int vhost_init_used(struct vhost_virtqueue *vq)
{
+ __virtio16 last_used_idx;
int r;
if (!vq->private_data)
return 0;
@@ -1046,7 +1047,13 @@ int vhost_init_used(struct vhost_virtqueue *vq)
if (r)
return r;
vq->signalled_used_valid = false;
- return get_user(vq->last_used_idx, &vq->used->idx);
+ if (!access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx))
+ return -EFAULT;
+ r = __get_user(last_used_idx, &vq->used->idx);
+ if (r)
+ return r;
+ vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
+ return 0;
}
EXPORT_SYMBOL_GPL(vhost_init_used);

@@ -1087,16 +1094,16 @@ static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
/* Each buffer in the virtqueues is actually a chain of descriptors. This
* function returns the next descriptor in the chain,
* or -1U if we're at the end. */
-static unsigned next_desc(struct vring_desc *desc)
+static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
{
unsigned int next;

/* If this descriptor says it doesn't chain, we're done. */
- if (!(desc->flags & VRING_DESC_F_NEXT))
+ if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
return -1U;

/* Check they're not leading us off end of descriptors. */
- next = desc->next;
+ next = vhost16_to_cpu(vq, desc->next);
/* Make sure compiler knows to grab that: we don't want it changing! */
/* We will use the result as an index in an array, so most
* architectures only need a compiler barrier here. */
@@ -1113,18 +1120,19 @@ static int get_indirect(struct vhost_virtqueue *vq,
{
struct vring_desc desc;
unsigned int i = 0, count, found = 0;
+ u32 len = vhost32_to_cpu(vq, indirect->len);
int ret;

/* Sanity check */
- if (unlikely(indirect->len % sizeof desc)) {
+ if (unlikely(len % sizeof desc)) {
vq_err(vq, "Invalid length in indirect descriptor: "
"len 0x%llx not multiple of 0x%zx\n",
- (unsigned long long)indirect->len,
+ (unsigned long long)vhost32_to_cpu(vq, indirect->len),
sizeof desc);
return -EINVAL;
}

- ret = translate_desc(vq, indirect->addr, indirect->len, vq->indirect,
+ ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
UIO_MAXIOV);
if (unlikely(ret < 0)) {
vq_err(vq, "Translation failure %d in indirect.\n", ret);
@@ -1135,7 +1143,7 @@ static int get_indirect(struct vhost_virtqueue *vq,
* architectures only need a compiler barrier here. */
read_barrier_depends();

- count = indirect->len / sizeof desc;
+ count = len / sizeof desc;
/* Buffers are chained via a 16 bit next field, so
* we can have at most 2^16 of these. */
if (unlikely(count > USHRT_MAX + 1)) {
@@ -1155,16 +1163,17 @@ static int get_indirect(struct vhost_virtqueue *vq,
if (unlikely(memcpy_fromiovec((unsigned char *)&desc,
vq->indirect, sizeof desc))) {
vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
- i, (size_t)indirect->addr + i * sizeof desc);
+ i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
return -EINVAL;
}
- if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) {
+ if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
- i, (size_t)indirect->addr + i * sizeof desc);
+ i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
return -EINVAL;
}

- ret = translate_desc(vq, desc.addr, desc.len, iov + iov_count,
+ ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
+ vhost32_to_cpu(vq, desc.len), iov + iov_count,
iov_size - iov_count);
if (unlikely(ret < 0)) {
vq_err(vq, "Translation failure %d indirect idx %d\n",
@@ -1172,11 +1181,11 @@ static int get_indirect(struct vhost_virtqueue *vq,
return ret;
}
/* If this is an input descriptor, increment that count. */
- if (desc.flags & VRING_DESC_F_WRITE) {
+ if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE)) {
*in_num += ret;
if (unlikely(log)) {
- log[*log_num].addr = desc.addr;
- log[*log_num].len = desc.len;
+ log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
+ log[*log_num].len = vhost32_to_cpu(vq, desc.len);
++*log_num;
}
} else {
@@ -1189,7 +1198,7 @@ static int get_indirect(struct vhost_virtqueue *vq,
}
*out_num += ret;
}
- } while ((i = next_desc(&desc)) != -1);
+ } while ((i = next_desc(vq, &desc)) != -1);
return 0;
}

@@ -1209,15 +1218,18 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
struct vring_desc desc;
unsigned int i, head, found = 0;
u16 last_avail_idx;
+ __virtio16 avail_idx;
+ __virtio16 ring_head;
int ret;

/* Check it isn't doing very strange things with descriptor numbers. */
last_avail_idx = vq->last_avail_idx;
- if (unlikely(__get_user(vq->avail_idx, &vq->avail->idx))) {
+ if (unlikely(__get_user(avail_idx, &vq->avail->idx))) {
vq_err(vq, "Failed to access avail idx at %p\n",
&vq->avail->idx);
return -EFAULT;
}
+ vq->avail_idx = vhost16_to_cpu(vq, avail_idx);

if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
vq_err(vq, "Guest moved used index from %u to %u",
@@ -1234,7 +1246,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,

/* Grab the next descriptor number they're advertising, and increment
* the index we've seen. */
- if (unlikely(__get_user(head,
+ if (unlikely(__get_user(ring_head,
&vq->avail->ring[last_avail_idx % vq->num]))) {
vq_err(vq, "Failed to read head: idx %d address %p\n",
last_avail_idx,
@@ -1242,6 +1254,8 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
return -EFAULT;
}

+ head = vhost16_to_cpu(vq, ring_head);
+
/* If their number is silly, that's an error. */
if (unlikely(head >= vq->num)) {
vq_err(vq, "Guest says index %u > %u is available",
@@ -1274,7 +1288,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
i, vq->desc + i);
return -EFAULT;
}
- if (desc.flags & VRING_DESC_F_INDIRECT) {
+ if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
ret = get_indirect(vq, iov, iov_size,
out_num, in_num,
log, log_num, &desc);
@@ -1286,20 +1300,21 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
continue;
}

- ret = translate_desc(vq, desc.addr, desc.len, iov + iov_count,
+ ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
+ vhost32_to_cpu(vq, desc.len), iov + iov_count,
iov_size - iov_count);
if (unlikely(ret < 0)) {
vq_err(vq, "Translation failure %d descriptor idx %d\n",
ret, i);
return ret;
}
- if (desc.flags & VRING_DESC_F_WRITE) {
+ if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE)) {
/* If this is an input descriptor,
* increment that count. */
*in_num += ret;
if (unlikely(log)) {
- log[*log_num].addr = desc.addr;
- log[*log_num].len = desc.len;
+ log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
+ log[*log_num].len = vhost32_to_cpu(vq, desc.len);
++*log_num;
}
} else {
@@ -1312,7 +1327,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
}
*out_num += ret;
}
- } while ((i = next_desc(&desc)) != -1);
+ } while ((i = next_desc(vq, &desc)) != -1);

/* On success, increment avail index. */
vq->last_avail_idx++;
@@ -1335,7 +1350,10 @@ EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
* want to notify the guest, using eventfd. */
int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
{
- struct vring_used_elem heads = { head, len };
+ struct vring_used_elem heads = {
+ cpu_to_vhost32(vq, head),
+ cpu_to_vhost32(vq, len)
+ };

return vhost_add_used_n(vq, &heads, 1);
}
@@ -1404,7 +1422,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,

/* Make sure buffer is written before we update index. */
smp_wmb();
- if (put_user(vq->last_used_idx, &vq->used->idx)) {
+ if (__put_user(cpu_to_vhost16(vq, vq->last_used_idx), &vq->used->idx)) {
vq_err(vq, "Failed to increment used idx");
return -EFAULT;
}
@@ -1422,7 +1440,8 @@ EXPORT_SYMBOL_GPL(vhost_add_used_n);

static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
- __u16 old, new, event;
+ __u16 old, new;
+ __virtio16 event;
bool v;
/* Flush out used index updates. This is paired
* with the barrier that the Guest executes when enabling
@@ -1434,12 +1453,12 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
return true;

if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
- __u16 flags;
+ __virtio16 flags;
if (__get_user(flags, &vq->avail->flags)) {
vq_err(vq, "Failed to get flags");
return true;
}
- return !(flags & VRING_AVAIL_F_NO_INTERRUPT);
+ return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
}
old = vq->signalled_used;
v = vq->signalled_used_valid;
@@ -1449,11 +1468,11 @@ static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
if (unlikely(!v))
return true;

- if (get_user(event, vhost_used_event(vq))) {
+ if (__get_user(event, vhost_used_event(vq))) {
vq_err(vq, "Failed to get used event idx");
return true;
}
- return vring_need_event(event, new, old);
+ return vring_need_event(vhost16_to_cpu(vq, event), new, old);
}

/* This actually signals the guest, using eventfd. */
@@ -1488,7 +1507,7 @@ EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
/* OK, now we need to know about added descriptors. */
bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
- u16 avail_idx;
+ __virtio16 avail_idx;
int r;

if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
@@ -1519,7 +1538,7 @@ bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
return false;
}

- return avail_idx != vq->avail_idx;
+ return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
}
EXPORT_SYMBOL_GPL(vhost_enable_notify);

--
MST

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