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authorRusty Russell <rusty@rustcorp.com.au>2008-05-02 21:50:49 -0500
committerRusty Russell <rusty@rustcorp.com.au>2008-05-02 21:50:50 +1000
commit72e61eb40b55dd57031ec5971e810649f82b0259 (patch)
tree66a836c7799b21156d4fc87f42e5817d7d95535b
parent5539ae9613587e4a4eec42d420b8bdd9ff552a65 (diff)
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virtio: change config to guest endian.
A recent proposed feature addition to the virtio block driver revealed some flaws in the API, in particular how easy it is to break big endian machines. The virtio config space was originally chosen to be little-endian, because we thought the config might be part of the PCI config space for virtio_pci. It's actually a separate mmio region, so that argument holds little water; as only x86 is currently using the virtio mechanism, we can change this (but must do so now, before the impending s390 merge). API changes: - __virtio_config_val() just becomes a striaght vdev->config_get() call. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--drivers/block/virtio_blk.c4
-rw-r--r--drivers/virtio/virtio_balloon.c6
-rw-r--r--include/linux/virtio_config.h47
3 files changed, 21 insertions, 36 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 7e83b6c..cc6d393 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -246,8 +246,8 @@ static int virtblk_probe(struct virtio_device *vdev)
blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL);
/* Host must always specify the capacity. */
- __virtio_config_val(vdev, offsetof(struct virtio_blk_config, capacity),
- &cap);
+ vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
+ &cap, sizeof(cap));
/* If capacity is too big, truncate with warning. */
if ((sector_t)cap != cap) {
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 0b3efc3..fef88d8 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -155,9 +155,9 @@ static void virtballoon_changed(struct virtio_device *vdev)
static inline s64 towards_target(struct virtio_balloon *vb)
{
u32 v;
- __virtio_config_val(vb->vdev,
- offsetof(struct virtio_balloon_config, num_pages),
- &v);
+ vb->vdev->config->get(vb->vdev,
+ offsetof(struct virtio_balloon_config, num_pages),
+ &v, sizeof(v));
return v - vb->num_pages;
}
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index d581b29..475572e 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -16,7 +16,7 @@
#define VIRTIO_CONFIG_S_FAILED 0x80
#ifdef __KERNEL__
-struct virtio_device;
+#include <linux/virtio.h>
/**
* virtio_config_ops - operations for configuring a virtio device
@@ -30,13 +30,11 @@ struct virtio_device;
* offset: the offset of the configuration field
* buf: the buffer to write the field value into.
* len: the length of the buffer
- * Note that contents are conventionally little-endian.
* @set: write the value of a configuration field
* vdev: the virtio_device
* offset: the offset of the configuration field
* buf: the buffer to read the field value from.
* len: the length of the buffer
- * Note that contents are conventionally little-endian.
* @get_status: read the status byte
* vdev: the virtio_device
* Returns the status byte
@@ -70,40 +68,27 @@ struct virtio_config_ops
};
/**
- * virtio_config_val - look for a feature and get a single virtio config.
+ * virtio_config_val - look for a feature and get a virtio config entry.
* @vdev: the virtio device
* @fbit: the feature bit
* @offset: the type to search for.
* @val: a pointer to the value to fill in.
*
* The return value is -ENOENT if the feature doesn't exist. Otherwise
- * the value is endian-corrected and returned in v. */
-#define virtio_config_val(vdev, fbit, offset, v) ({ \
- int _err; \
- if ((vdev)->config->feature((vdev), (fbit))) { \
- __virtio_config_val((vdev), (offset), (v)); \
- _err = 0; \
- } else \
- _err = -ENOENT; \
- _err; \
-})
+ * the config value is copied into whatever is pointed to by v. */
+#define virtio_config_val(vdev, fbit, offset, v) \
+ virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(v))
-/**
- * __virtio_config_val - get a single virtio config without feature check.
- * @vdev: the virtio device
- * @offset: the type to search for.
- * @val: a pointer to the value to fill in.
- *
- * The value is endian-corrected and returned in v. */
-#define __virtio_config_val(vdev, offset, v) do { \
- BUILD_BUG_ON(sizeof(*(v)) != 1 && sizeof(*(v)) != 2 \
- && sizeof(*(v)) != 4 && sizeof(*(v)) != 8); \
- (vdev)->config->get((vdev), (offset), (v), sizeof(*(v))); \
- switch (sizeof(*(v))) { \
- case 2: le16_to_cpus((__u16 *) v); break; \
- case 4: le32_to_cpus((__u32 *) v); break; \
- case 8: le64_to_cpus((__u64 *) v); break; \
- } \
-} while(0)
+static inline int virtio_config_buf(struct virtio_device *vdev,
+ unsigned int fbit,
+ unsigned int offset,
+ void *buf, unsigned len)
+{
+ if (!vdev->config->feature(vdev, fbit))
+ return -ENOENT;
+
+ vdev->config->get(vdev, offset, buf, len);
+ return 0;
+}
#endif /* __KERNEL__ */
#endif /* _LINUX_VIRTIO_CONFIG_H */