Subject: Re: [PATCH v3 26/41] vhost: virtio 1.0 endian-ness support

From: Cedric Le Goater <[email-masked]>
Date: Mon, 24 Nov 2014 15:28:26 +0100

Hi Michael,

Do you have a tree from where I could pull these patches ? 

Thanks,

C.

On 11/24/2014 12:54 PM, Michael S. Tsirkin wrote:
> Signed-off-by: Michael S. Tsirkin <[email-masked]>
> ---
>  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);
>