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authorRusty Russell <rusty@rustcorp.com.au>2008-02-04 23:49:56 -0500
committerRusty Russell <rusty@rustcorp.com.au>2008-02-04 23:49:57 +1100
commita586d4f6016f7139d8c26df0e6927131168d3b5b (patch)
tree1c47e1a6b6b8fb18baa42f32980f29c4ae9cbbdc /drivers
parentf35d9d8aae08940b7fdd1bb8110619da2ece6b28 (diff)
downloadop-kernel-dev-a586d4f6016f7139d8c26df0e6927131168d3b5b.zip
op-kernel-dev-a586d4f6016f7139d8c26df0e6927131168d3b5b.tar.gz
virtio: simplify config mechanism.
Previously we used a type/len pair within the config space, but this seems overkill. We now simply define a structure which represents the layout in the config space: the config space can now only be extended at the end. The main driver-visible changes: 1) We indicate what fields are present with an explicit feature bit. 2) Virtqueues are explicitly numbered, and not in the config space. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/block/virtio_blk.c35
-rw-r--r--drivers/char/virtio_console.c4
-rw-r--r--drivers/lguest/lguest_device.c132
-rw-r--r--drivers/net/virtio_net.c25
-rw-r--r--drivers/virtio/virtio.c45
5 files changed, 100 insertions, 141 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 924ddd8..1c63d5b 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -162,8 +162,6 @@ static int virtblk_probe(struct virtio_device *vdev)
{
struct virtio_blk *vblk;
int err, major;
- void *token;
- unsigned int len;
u64 cap;
u32 v;
@@ -178,7 +176,7 @@ static int virtblk_probe(struct virtio_device *vdev)
vblk->vdev = vdev;
/* We expect one virtqueue, for output. */
- vblk->vq = vdev->config->find_vq(vdev, blk_done);
+ vblk->vq = vdev->config->find_vq(vdev, 0, blk_done);
if (IS_ERR(vblk->vq)) {
err = PTR_ERR(vblk->vq);
goto out_free_vblk;
@@ -216,15 +214,12 @@ static int virtblk_probe(struct virtio_device *vdev)
vblk->disk->fops = &virtblk_fops;
/* If barriers are supported, tell block layer that queue is ordered */
- token = vdev->config->find(vdev, VIRTIO_CONFIG_BLK_F, &len);
- if (virtio_use_bit(vdev, token, len, VIRTIO_BLK_F_BARRIER))
+ if (vdev->config->feature(vdev, VIRTIO_BLK_F_BARRIER))
blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL);
- err = virtio_config_val(vdev, VIRTIO_CONFIG_BLK_F_CAPACITY, &cap);
- if (err) {
- dev_err(&vdev->dev, "Bad/missing capacity in config\n");
- goto out_cleanup_queue;
- }
+ /* Host must always specify the capacity. */
+ __virtio_config_val(vdev, offsetof(struct virtio_blk_config, capacity),
+ &cap);
/* If capacity is too big, truncate with warning. */
if ((sector_t)cap != cap) {
@@ -234,27 +229,23 @@ static int virtblk_probe(struct virtio_device *vdev)
}
set_capacity(vblk->disk, cap);
- err = virtio_config_val(vdev, VIRTIO_CONFIG_BLK_F_SIZE_MAX, &v);
+ /* Host can optionally specify maximum segment size and number of
+ * segments. */
+ err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX,
+ offsetof(struct virtio_blk_config, size_max),
+ &v);
if (!err)
blk_queue_max_segment_size(vblk->disk->queue, v);
- else if (err != -ENOENT) {
- dev_err(&vdev->dev, "Bad SIZE_MAX in config\n");
- goto out_cleanup_queue;
- }
- err = virtio_config_val(vdev, VIRTIO_CONFIG_BLK_F_SEG_MAX, &v);
+ err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX,
+ offsetof(struct virtio_blk_config, seg_max),
+ &v);
if (!err)
blk_queue_max_hw_segments(vblk->disk->queue, v);
- else if (err != -ENOENT) {
- dev_err(&vdev->dev, "Bad SEG_MAX in config\n");
- goto out_cleanup_queue;
- }
add_disk(vblk->disk);
return 0;
-out_cleanup_queue:
- blk_cleanup_queue(vblk->disk->queue);
out_put_disk:
put_disk(vblk->disk);
out_unregister_blkdev:
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index e34da5c..dc17fe3 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -158,13 +158,13 @@ static int __devinit virtcons_probe(struct virtio_device *dev)
/* Find the input queue. */
/* FIXME: This is why we want to wean off hvc: we do nothing
* when input comes in. */
- in_vq = vdev->config->find_vq(vdev, NULL);
+ in_vq = vdev->config->find_vq(vdev, 0, NULL);
if (IS_ERR(in_vq)) {
err = PTR_ERR(in_vq);
goto free;
}
- out_vq = vdev->config->find_vq(vdev, NULL);
+ out_vq = vdev->config->find_vq(vdev, 1, NULL);
if (IS_ERR(out_vq)) {
err = PTR_ERR(out_vq);
goto free_in_vq;
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index e2eec38..07f57a5 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -52,57 +52,82 @@ struct lguest_device {
/*D:130
* Device configurations
*
- * The configuration information for a device consists of a series of fields.
- * We don't really care what they are: the Launcher set them up, and the driver
- * will look at them during setup.
+ * The configuration information for a device consists of one or more
+ * virtqueues, a feature bitmaks, and some configuration bytes. The
+ * configuration bytes don't really matter to us: the Launcher set them up, and
+ * the driver will look at them during setup.
*
- * For us these fields come immediately after that device's descriptor in the
- * lguest_devices page.
- *
- * Each field starts with a "type" byte, a "length" byte, then that number of
- * bytes of configuration information. The device descriptor tells us the
- * total configuration length so we know when we've reached the last field. */
+ * A convenient routine to return the device's virtqueue config array:
+ * immediately after the descriptor. */
+static struct lguest_vqconfig *lg_vq(const struct lguest_device_desc *desc)
+{
+ return (void *)(desc + 1);
+}
-/* type + length bytes */
-#define FHDR_LEN 2
+/* The features come immediately after the virtqueues. */
+static u8 *lg_features(const struct lguest_device_desc *desc)
+{
+ return (void *)(lg_vq(desc) + desc->num_vq);
+}
-/* This finds the first field of a given type for a device's configuration. */
-static void *lg_find(struct virtio_device *vdev, u8 type, unsigned int *len)
+/* The config space comes after the two feature bitmasks. */
+static u8 *lg_config(const struct lguest_device_desc *desc)
{
- struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
- int i;
-
- for (i = 0; i < desc->config_len; i += FHDR_LEN + desc->config[i+1]) {
- if (desc->config[i] == type) {
- /* Mark it used, so Host can know we looked at it, and
- * also so we won't find the same one twice. */
- desc->config[i] |= 0x80;
- /* Remember, the second byte is the length. */
- *len = desc->config[i+1];
- /* We return a pointer to the field header. */
- return desc->config + i;
- }
- }
+ return lg_features(desc) + desc->feature_len * 2;
+}
- /* Not found: return NULL for failure. */
- return NULL;
+/* The total size of the config page used by this device (incl. desc) */
+static unsigned desc_size(const struct lguest_device_desc *desc)
+{
+ return sizeof(*desc)
+ + desc->num_vq * sizeof(struct lguest_vqconfig)
+ + desc->feature_len * 2
+ + desc->config_len;
+}
+
+/* This tests (and acknowleges) a feature bit. */
+static bool lg_feature(struct virtio_device *vdev, unsigned fbit)
+{
+ struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
+ u8 *features;
+
+ /* Obviously if they ask for a feature off the end of our feature
+ * bitmap, it's not set. */
+ if (fbit / 8 > desc->feature_len)
+ return false;
+
+ /* The feature bitmap comes after the virtqueues. */
+ features = lg_features(desc);
+ if (!(features[fbit / 8] & (1 << (fbit % 8))))
+ return false;
+
+ /* We set the matching bit in the other half of the bitmap to tell the
+ * Host we want to use this feature. We don't use this yet, but we
+ * could in future. */
+ features[desc->feature_len + fbit / 8] |= (1 << (fbit % 8));
+ return true;
}
/* Once they've found a field, getting a copy of it is easy. */
-static void lg_get(struct virtio_device *vdev, void *token,
+static void lg_get(struct virtio_device *vdev, unsigned int offset,
void *buf, unsigned len)
{
- /* Check they didn't ask for more than the length of the field! */
- BUG_ON(len > ((u8 *)token)[1]);
- memcpy(buf, token + FHDR_LEN, len);
+ struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
+
+ /* Check they didn't ask for more than the length of the config! */
+ BUG_ON(offset + len > desc->config_len);
+ memcpy(buf, lg_config(desc) + offset, len);
}
/* Setting the contents is also trivial. */
-static void lg_set(struct virtio_device *vdev, void *token,
+static void lg_set(struct virtio_device *vdev, unsigned int offset,
const void *buf, unsigned len)
{
- BUG_ON(len > ((u8 *)token)[1]);
- memcpy(token + FHDR_LEN, buf, len);
+ struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
+
+ /* Check they didn't ask for more than the length of the config! */
+ BUG_ON(offset + len > desc->config_len);
+ memcpy(lg_config(desc) + offset, buf, len);
}
/* The operations to get and set the status word just access the status field
@@ -165,39 +190,29 @@ static void lg_notify(struct virtqueue *vq)
*
* So we provide devices with a "find virtqueue and set it up" function. */
static struct virtqueue *lg_find_vq(struct virtio_device *vdev,
+ unsigned index,
bool (*callback)(struct virtqueue *vq))
{
+ struct lguest_device *ldev = to_lgdev(vdev);
struct lguest_vq_info *lvq;
struct virtqueue *vq;
- unsigned int len;
- void *token;
int err;
- /* Look for a field of the correct type to mark a virtqueue. Note that
- * if this succeeds, then the type will be changed so it won't be found
- * again, and future lg_find_vq() calls will find the next
- * virtqueue (if any). */
- token = vdev->config->find(vdev, VIRTIO_CONFIG_F_VIRTQUEUE, &len);
- if (!token)
+ /* We must have this many virtqueues. */
+ if (index >= ldev->desc->num_vq)
return ERR_PTR(-ENOENT);
lvq = kmalloc(sizeof(*lvq), GFP_KERNEL);
if (!lvq)
return ERR_PTR(-ENOMEM);
- /* Note: we could use a configuration space inside here, just like we
- * do for the device. This would allow expansion in future, because
- * our configuration system is designed to be expansible. But this is
- * way easier. */
- if (len != sizeof(lvq->config)) {
- dev_err(&vdev->dev, "Unexpected virtio config len %u\n", len);
- err = -EIO;
- goto free_lvq;
- }
- /* Make a copy of the "struct lguest_vqconfig" field. We need a copy
- * because the config space might not be aligned correctly. */
- vdev->config->get(vdev, token, &lvq->config, sizeof(lvq->config));
+ /* Make a copy of the "struct lguest_vqconfig" entry, which sits after
+ * the descriptor. We need a copy because the config space might not
+ * be aligned correctly. */
+ memcpy(&lvq->config, lg_vq(ldev->desc)+index, sizeof(lvq->config));
+ printk("Mapping virtqueue %i addr %lx\n", index,
+ (unsigned long)lvq->config.pfn << PAGE_SHIFT);
/* Figure out how many pages the ring will take, and map that memory */
lvq->pages = lguest_map((unsigned long)lvq->config.pfn << PAGE_SHIFT,
DIV_ROUND_UP(vring_size(lvq->config.num,
@@ -259,7 +274,7 @@ static void lg_del_vq(struct virtqueue *vq)
/* The ops structure which hooks everything together. */
static struct virtio_config_ops lguest_config_ops = {
- .find = lg_find,
+ .feature = lg_feature,
.get = lg_get,
.set = lg_set,
.get_status = lg_get_status,
@@ -329,13 +344,14 @@ static void scan_devices(void)
struct lguest_device_desc *d;
/* We start at the page beginning, and skip over each entry. */
- for (i = 0; i < PAGE_SIZE; i += sizeof(*d) + d->config_len) {
+ for (i = 0; i < PAGE_SIZE; i += desc_size(d)) {
d = lguest_devices + i;
/* Once we hit a zero, stop. */
if (d->type == 0)
break;
+ printk("Device at %i has size %u\n", i, desc_size(d));
add_lguest_device(d);
}
}
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index a60505c..4b81383 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -311,10 +311,8 @@ static int virtnet_close(struct net_device *dev)
static int virtnet_probe(struct virtio_device *vdev)
{
int err;
- unsigned int len;
struct net_device *dev;
struct virtnet_info *vi;
- void *token;
/* Allocate ourselves a network device with room for our info */
dev = alloc_etherdev(sizeof(struct virtnet_info));
@@ -330,25 +328,24 @@ static int virtnet_probe(struct virtio_device *vdev)
SET_NETDEV_DEV(dev, &vdev->dev);
/* Do we support "hardware" checksums? */
- token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_F, &len);
- if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_NO_CSUM)) {
+ if (vdev->config->feature(vdev, VIRTIO_NET_F_NO_CSUM)) {
/* This opens up the world of extra features. */
dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
- if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4))
+ if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO4))
dev->features |= NETIF_F_TSO;
- if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_UFO))
+ if (vdev->config->feature(vdev, VIRTIO_NET_F_UFO))
dev->features |= NETIF_F_UFO;
- if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4_ECN))
+ if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO4_ECN))
dev->features |= NETIF_F_TSO_ECN;
- if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO6))
+ if (vdev->config->feature(vdev, VIRTIO_NET_F_TSO6))
dev->features |= NETIF_F_TSO6;
}
/* Configuration may specify what MAC to use. Otherwise random. */
- token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_MAC_F, &len);
- if (token) {
- dev->addr_len = len;
- vdev->config->get(vdev, token, dev->dev_addr, len);
+ if (vdev->config->feature(vdev, VIRTIO_NET_F_MAC)) {
+ vdev->config->get(vdev,
+ offsetof(struct virtio_net_config, mac),
+ dev->dev_addr, dev->addr_len);
} else
random_ether_addr(dev->dev_addr);
@@ -359,13 +356,13 @@ static int virtnet_probe(struct virtio_device *vdev)
vi->vdev = vdev;
/* We expect two virtqueues, receive then send. */
- vi->rvq = vdev->config->find_vq(vdev, skb_recv_done);
+ vi->rvq = vdev->config->find_vq(vdev, 0, skb_recv_done);
if (IS_ERR(vi->rvq)) {
err = PTR_ERR(vi->rvq);
goto free;
}
- vi->svq = vdev->config->find_vq(vdev, skb_xmit_done);
+ vi->svq = vdev->config->find_vq(vdev, 1, skb_xmit_done);
if (IS_ERR(vi->svq)) {
err = PTR_ERR(vi->svq);
goto free_recv;
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 69d7ea0..303cb6f 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -148,51 +148,6 @@ void unregister_virtio_device(struct virtio_device *dev)
}
EXPORT_SYMBOL_GPL(unregister_virtio_device);
-int __virtio_config_val(struct virtio_device *vdev,
- u8 type, void *val, size_t size)
-{
- void *token;
- unsigned int len;
-
- token = vdev->config->find(vdev, type, &len);
- if (!token)
- return -ENOENT;
-
- if (len != size)
- return -EIO;
-
- vdev->config->get(vdev, token, val, size);
- return 0;
-}
-EXPORT_SYMBOL_GPL(__virtio_config_val);
-
-int virtio_use_bit(struct virtio_device *vdev,
- void *token, unsigned int len, unsigned int bitnum)
-{
- unsigned long bits[16];
-
- /* This makes it convenient to pass-through find() results. */
- if (!token)
- return 0;
-
- /* bit not in range of this bitfield? */
- if (bitnum * 8 >= len / 2)
- return 0;
-
- /* Giant feature bitfields are silly. */
- BUG_ON(len > sizeof(bits));
- vdev->config->get(vdev, token, bits, len);
-
- if (!test_bit(bitnum, bits))
- return 0;
-
- /* Set acknowledge bit, and write it back. */
- set_bit(bitnum + len * 8 / 2, bits);
- vdev->config->set(vdev, token, bits, len);
- return 1;
-}
-EXPORT_SYMBOL_GPL(virtio_use_bit);
-
static int virtio_init(void)
{
if (bus_register(&virtio_bus) != 0)
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