Dor Laor
2007-Dec-21 07:17 UTC
[kvm-devel] [Virtio-for-kvm] [PATCH 1/13] [Mostly resend] virtio additions
From 5d85cee1fb14608b79b5b6103d8be2d90bb76ca4 Mon Sep 17 00:00:00 2001
From: Anthony Liguori <aliguori@us.ibm.com>
Date: Mon, 12 Nov 2007 21:30:26 -0600
Subject: [PATCH] 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>
---
Documentation/lguest/lguest.c | 176
+++++++++++++++++++++++----------------
drivers/block/virtio_blk.c | 35 +++-----
drivers/char/virtio_console.c | 4 +-
drivers/lguest/lguest_device.c | 134 +++++++++++++++++-------------
drivers/net/virtio_net.c | 25 +++---
drivers/virtio/virtio.c | 45 ----------
include/linux/lguest_launcher.h | 9 ++-
include/linux/virtio_blk.h | 22 +++--
include/linux/virtio_config.h | 98 ++++++++++------------
include/linux/virtio_net.h | 11 ++-
net/9p/trans_virtio.c | 4 +-
11 files changed, 282 insertions(+), 281 deletions(-)
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index 9b0e322..029cc7c 100644
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -34,6 +34,8 @@
#include <zlib.h>
#include <assert.h>
#include <sched.h>
+#include <limits.h>
+#include <stddef.h>
#include "linux/lguest_launcher.h"
#include "linux/virtio_config.h"
#include "linux/virtio_net.h"
@@ -96,13 +98,11 @@ struct device_list
/* The descriptor page for the devices. */
u8 *descpage;
- /* The tail of the last descriptor. */
- unsigned int desc_used;
-
/* A single linked list of devices. */
struct device *dev;
- /* ... And an end pointer so we can easily append new devices */
- struct device **lastdev;
+ /* And a pointer to the last device for easy append and also for
+ * configuration appending. */
+ struct device *lastdev;
};
/* The list of Guest devices, based on command line arguments. */
@@ -185,7 +185,7 @@ static void *_convert(struct iovec *iov, size_t
size, size_t align,
#define cpu_to_le64(v64) (v64)
#define le16_to_cpu(v16) (v16)
#define le32_to_cpu(v32) (v32)
-#define le64_to_cpu(v32) (v64)
+#define le64_to_cpu(v64) (v64)
/*L:100 The Launcher code itself takes us out into userspace, that
scary place
* where pointers run wild and free! Unfortunately, like most userspace
@@ -980,54 +980,44 @@ static void handle_input(int fd)
*
* All devices need a descriptor so the Guest knows it exists, and a
"struct
* device" so the Launcher can keep track of it. We have common helper
- * routines to allocate them.
- *
- * This routine allocates a new "struct lguest_device_desc" from
descriptor
- * table just above the Guest's normal memory. It returns a pointer to
that
- * descriptor. */
-static struct lguest_device_desc *new_dev_desc(u16 type)
-{
- struct lguest_device_desc *d;
+ * routines to allocate and manage them. */
- /* We only have one page for all the descriptors. */
- if (devices.desc_used + sizeof(*d) > getpagesize())
- errx(1, "Too many devices");
-
- /* We don't need to set config_len or status: page is 0 already. */
- d = (void *)devices.descpage + devices.desc_used;
- d->type = type;
- devices.desc_used += sizeof(*d);
-
- return d;
+/* The layout of the device page is a "struct lguest_device_desc"
followed by a
+ * number of virtqueue descriptors, then two sets of feature bits, then an
+ * array of configuration bytes. This routine returns the configuration
+ * pointer. */
+static u8 *device_config(const struct device *dev)
+{
+ return (void *)(dev->desc + 1)
+ + dev->desc->num_vq * sizeof(struct lguest_vqconfig)
+ + dev->desc->feature_len * 2;
}
-/* Each device descriptor is followed by some configuration information.
- * Each configuration field looks like: u8 type, u8 len, [... len
bytes...].
- *
- * This routine adds a new field to an existing device's descriptor.
It only
- * works for the last device, but that's OK because that's how we use
it. */
-static void add_desc_field(struct device *dev, u8 type, u8 len, const
void *c)
+/* This routine allocates a new "struct lguest_device_desc" from
descriptor
+ * table page just above the Guest's normal memory. It returns a
pointer to
+ * that descriptor. */
+static struct lguest_device_desc *new_dev_desc(u16 type)
{
- /* This is the last descriptor, right? */
- assert(devices.descpage + devices.desc_used
- == (u8 *)(dev->desc + 1) + dev->desc->config_len);
+ struct lguest_device_desc d = { .type = type };
+ void *p;
- /* We only have one page of device descriptions. */
- if (devices.desc_used + 2 + len > getpagesize())
- errx(1, "Too many devices");
+ /* Figure out where the next device config is, based on the last
one. */
+ if (devices.lastdev)
+ p = device_config(devices.lastdev)
+ + devices.lastdev->desc->config_len;
+ else
+ p = devices.descpage;
- /* Copy in the new config header: type then length. */
- devices.descpage[devices.desc_used++] = type;
- devices.descpage[devices.desc_used++] = len;
- memcpy(devices.descpage + devices.desc_used, c, len);
- devices.desc_used += len;
+ /* We only have one page for all the descriptors. */
+ if (p + sizeof(d) > (void *)devices.descpage + getpagesize())
+ errx(1, "Too many devices");
- /* Update the device descriptor length: two byte head then data. */
- dev->desc->config_len += 2 + len;
+ /* p might not be aligned, so we memcpy in. */
+ return memcpy(p, &d, sizeof(d));
}
-/* This routine adds a virtqueue to a device. We specify how many
descriptors
- * the virtqueue is to have. */
+/* Each device descriptor is followed by the description of its
virtqueues. We
+ * specify how many descriptors the virtqueue is to have. */
static void add_virtqueue(struct device *dev, unsigned int num_descs,
void (*handle_output)(int fd, struct virtqueue *me))
{
@@ -1053,9 +1043,15 @@ static void add_virtqueue(struct device *dev,
unsigned int num_descs,
/* Initialize the vring. */
vring_init(&vq->vring, num_descs, p, getpagesize());
- /* Add the configuration information to this device's descriptor. */
- add_desc_field(dev, VIRTIO_CONFIG_F_VIRTQUEUE,
- sizeof(vq->config), &vq->config);
+ /* Append virtqueue to this device's descriptor. We use
+ * device_config() to get the end of the device's current virtqueues;
+ * we check that we haven't added any config or feature information
+ * yet, otherwise we'd be overwriting them. */
+ assert(dev->desc->config_len == 0 &&
dev->desc->feature_len == 0);
+ memcpy(device_config(dev), &vq->config, sizeof(vq->config));
+ dev->desc->num_vq++;
+
+ verbose("Virtqueue page %#lx\n", to_guest_phys(p));
/* Add to tail of list, so dev->vq is first vq, dev->vq->next is
* second. */
@@ -1071,6 +1067,37 @@ static void add_virtqueue(struct device *dev,
unsigned int num_descs,
vq->vring.used->flags = VRING_USED_F_NO_NOTIFY;
}
+/* The virtqueue descriptors are followed by feature bytes. */
+static void add_feature(struct device *dev, unsigned bit)
+{
+ u8 *features;
+
+ /* We can't extend the feature bits once we've added config bytes
*/
+ if (dev->desc->feature_len <= bit / CHAR_BIT) {
+ assert(dev->desc->config_len == 0);
+ dev->desc->feature_len = (bit / CHAR_BIT) + 1;
+ }
+
+ features = (u8 *)(dev->desc + 1)
+ + dev->desc->num_vq * sizeof(struct lguest_vqconfig);
+
+ features[bit / CHAR_BIT] |= (1 << (bit % CHAR_BIT));
+}
+
+/* This routine sets the configuration fields for an existing device's
+ * descriptor. It only works for the last device, but that's OK
because that's
+ * how we use it. */
+static void set_config(struct device *dev, unsigned len, const void *conf)
+{
+ /* Check we haven't overflowed our single page. */
+ if (device_config(dev) + len > devices.descpage + getpagesize())
+ errx(1, "Too many devices");
+
+ /* Copy in the config information, and store the length. */
+ memcpy(device_config(dev), conf, len);
+ dev->desc->config_len = len;
+}
+
/* This routine does all the creation and setup of a new device, including
* calling new_dev_desc() to allocate the descriptor and device memory. */
static struct device *new_device(const char *name, u16 type, int fd,
@@ -1078,14 +1105,6 @@ static struct device *new_device(const char
*name, u16 type, int fd,
{
struct device *dev = malloc(sizeof(*dev));
- /* Append to device list. Prepending to a single-linked list is
- * easier, but the user expects the devices to be arranged on the bus
- * in command-line order. The first network device on the command line
- * is eth0, the first block device /dev/vda, etc. */
- *devices.lastdev = dev;
- dev->next = NULL;
- devices.lastdev = &dev->next;
-
/* Now we populate the fields one at a time. */
dev->fd = fd;
/* If we have an input handler for this file descriptor, then we add it
@@ -1096,6 +1115,17 @@ static struct device *new_device(const char
*name, u16 type, int fd,
dev->handle_input = handle_input;
dev->name = name;
dev->vq = NULL;
+
+ /* Append to device list. Prepending to a single-linked list is
+ * easier, but the user expects the devices to be arranged on the bus
+ * in command-line order. The first network device on the command line
+ * is eth0, the first block device /dev/vda, etc. */
+ if (devices.lastdev)
+ devices.lastdev->next = dev;
+ else
+ devices.dev = dev;
+ devices.lastdev = dev;
+
return dev;
}
@@ -1220,7 +1250,7 @@ static void setup_tun_net(const char *arg)
int netfd, ipfd;
u32 ip;
const char *br_name = NULL;
- u8 hwaddr[6];
+ struct virtio_net_config conf;
/* We open the /dev/net/tun device and tell it we want a tap device. A
* tap device is like a tun device, only somehow different. To tell
@@ -1259,12 +1289,13 @@ static void setup_tun_net(const char *arg)
ip = str2ip(arg);
/* Set up the tun device, and get the mac address for the interface. */
- configure_device(ipfd, ifr.ifr_name, ip, hwaddr);
+ configure_device(ipfd, ifr.ifr_name, ip, conf.mac);
/* Tell Guest what MAC address to use. */
- add_desc_field(dev, VIRTIO_CONFIG_NET_MAC_F, sizeof(hwaddr), hwaddr);
+ add_feature(dev, VIRTIO_NET_F_MAC);
+ set_config(dev, sizeof(conf), &conf);
- /* We don't seed the socket any more; setup is done. */
+ /* We don't need the socket any more; setup is done. */
close(ipfd);
verbose("device %u: tun net %u.%u.%u.%u\n",
@@ -1452,8 +1483,7 @@ static void setup_block_file(const char *filename)
struct device *dev;
struct vblk_info *vblk;
void *stack;
- u64 cap;
- unsigned int val;
+ struct virtio_blk_config conf;
/* This is the pipe the I/O thread will use to tell us I/O is done. */
pipe(p);
@@ -1471,14 +1501,18 @@ static void setup_block_file(const char *filename)
vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE);
vblk->len = lseek64(vblk->fd, 0, SEEK_END);
+ /* We support barriers. */
+ add_feature(dev, VIRTIO_BLK_F_BARRIER);
+
/* Tell Guest how many sectors this device has. */
- cap = cpu_to_le64(vblk->len / 512);
- add_desc_field(dev, VIRTIO_CONFIG_BLK_F_CAPACITY, sizeof(cap), &cap);
+ conf.capacity = cpu_to_le64(vblk->len / 512);
/* Tell Guest not to put in too many descriptors at once: two are used
* for the in and out elements. */
- val = cpu_to_le32(VIRTQUEUE_NUM - 2);
- add_desc_field(dev, VIRTIO_CONFIG_BLK_F_SEG_MAX, sizeof(val), &val);
+ add_feature(dev, VIRTIO_BLK_F_SEG_MAX);
+ conf.seg_max = cpu_to_le32(VIRTQUEUE_NUM - 2);
+
+ set_config(dev, sizeof(conf), &conf);
/* The I/O thread writes to this end of the pipe when done. */
vblk->done_fd = p[1];
@@ -1497,7 +1531,7 @@ static void setup_block_file(const char *filename)
close(vblk->workpipe[0]);
verbose("device %u: virtblock %llu sectors\n",
- devices.device_num, cap);
+ devices.device_num, le64_to_cpu(conf.capacity));
}
/* That's the end of device setup. */
@@ -1574,12 +1608,12 @@ int main(int argc, char *argv[])
/* First we initialize the device list. Since console and network
* device receive input from a file descriptor, we keep an fdset
* (infds) and the maximum fd number (max_infd) with the head of the
- * list. We also keep a pointer to the last device, for easy appending
- * to the list. Finally, we keep the next interrupt number to hand out
- * (1: remember that 0 is used by the timer). */
+ * list. We also keep a pointer to the last device. Finally, we keep
+ * the next interrupt number to hand out (1: remember that 0 is used by
+ * the timer). */
FD_ZERO(&devices.infds);
devices.max_infd = -1;
- devices.lastdev = &devices.dev;
+ devices.lastdev = NULL;
devices.next_irq = 1;
/* We need to know how much memory so we can set up the device
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..ecf73ef 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -52,57 +52,84 @@ 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);
+ printk("Getting config len %u from page offset %u\n",
+ len, lg_config(desc) + offset - (u8 *)lguest_devices);
+ 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 +192,29 @@ 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 +276,7 @@ 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 +346,14 @@ 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 5413dbf..aff25b0 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -320,10 +320,8 @@ 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));
@@ -339,25 +337,24 @@ 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);
@@ -368,13 +365,13 @@ 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)
diff --git a/include/linux/lguest_launcher.h
b/include/linux/lguest_launcher.h
index 697104d..589be3e 100644
--- a/include/linux/lguest_launcher.h
+++ b/include/linux/lguest_launcher.h
@@ -23,7 +23,12 @@
struct lguest_device_desc {
/* The device type: console, network, disk etc. Type 0 terminates. */
__u8 type;
- /* The number of bytes of the config array. */
+ /* The number of virtqueues (first in config array) */
+ __u8 num_vq;
+ /* The number of bytes of feature bits. Multiply by 2: one for host
+ * features and one for guest acknowledgements. */
+ __u8 feature_len;
+ /* The number of bytes of the config array after virtqueues. */
__u8 config_len;
/* A status byte, written by the Guest. */
__u8 status;
@@ -31,7 +36,7 @@ struct lguest_device_desc {
};
/*D:135 This is how we expect the device configuration field for a
virtqueue
- * (type VIRTIO_CONFIG_F_VIRTQUEUE) to be laid out: */
+ * to be laid out in config space. */
struct lguest_vqconfig {
/* The number of entries in the virtio_ring */
__u16 num;
diff --git a/include/linux/virtio_blk.h b/include/linux/virtio_blk.h
index 7bd2bce..e546356 100644
--- a/include/linux/virtio_blk.h
+++ b/include/linux/virtio_blk.h
@@ -6,15 +6,19 @@
#define VIRTIO_ID_BLOCK 2
/* Feature bits */
-#define VIRTIO_CONFIG_BLK_F 0x40
-#define VIRTIO_BLK_F_BARRIER 1 /* Does host support barriers? */
-
-/* The capacity (in 512-byte sectors). */
-#define VIRTIO_CONFIG_BLK_F_CAPACITY 0x41
-/* The maximum segment size. */
-#define VIRTIO_CONFIG_BLK_F_SIZE_MAX 0x42
-/* The maximum number of segments. */
-#define VIRTIO_CONFIG_BLK_F_SEG_MAX 0x43
+#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
+#define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */
+#define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */
+
+struct virtio_blk_config
+{
+ /* The capacity (in 512-byte sectors). */
+ __le64 capacity;
+ /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
+ __le32 size_max;
+ /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
+ __le32 seg_max;
+} __attribute__((packed));
/* These two define direction. */
#define VIRTIO_BLK_T_IN 0
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index bcc0188..70bb260 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -5,7 +5,7 @@
* store and access that space differently. */
#include <linux/types.h>
-/* Status byte for guest to report progress, and synchronize config. */
+/* Status byte for guest to report progress, and synchronize features. */
/* We have seen device and processed generic fields
(VIRTIO_CONFIG_F_VIRTIO) */
#define VIRTIO_CONFIG_S_ACKNOWLEDGE 1
/* We have found a driver for the device. */
@@ -15,34 +15,27 @@
/* We've given up on this device. */
#define VIRTIO_CONFIG_S_FAILED 0x80
-/* Feature byte (actually 7 bits availabe): */
-/* Requirements/features of the virtio implementation. */
-#define VIRTIO_CONFIG_F_VIRTIO 1
-/* Requirements/features of the virtqueue (may have more than one). */
-#define VIRTIO_CONFIG_F_VIRTQUEUE 2
-
#ifdef __KERNEL__
struct virtio_device;
/**
* virtio_config_ops - operations for configuring a virtio device
- * @find: search for the next configuration field of the given type.
+ * @feature: search for a feature in this config
* vdev: the virtio_device
- * type: the feature type
- * len: the (returned) length of the field if found.
- * Returns a token if found, or NULL. Never returnes the same field
twice
- * (ie. it's used up).
- * @get: read the value of a configuration field after find().
+ * bit: the feature bit
+ * Returns true if the feature is supported. Acknowledges the feature
+ * so the host can see it.
+ * @get: read the value of a configuration field
* vdev: the virtio_device
- * token: the token returned from find().
+ * offset: the offset of the configuration field
* buf: the buffer to write the field value into.
- * len: the length of the buffer (given by find()).
+ * len: the length of the buffer
* Note that contents are conventionally little-endian.
- * @set: write the value of a configuration field after find().
+ * @set: write the value of a configuration field
* vdev: the virtio_device
- * token: the token returned from find().
+ * offset: the offset of the configuration field
* buf: the buffer to read the field value from.
- * len: the length of the buffer (given by find()).
+ * len: the length of the buffer
* Note that contents are conventionally little-endian.
* @get_status: read the status byte
* vdev: the virtio_device
@@ -50,62 +43,63 @@ struct virtio_device;
* @set_status: write the status byte
* vdev: the virtio_device
* status: the new status byte
- * @find_vq: find the first VIRTIO_CONFIG_F_VIRTQUEUE and create a
virtqueue.
+ * @find_vq: find a virtqueue and instantiate it.
* vdev: the virtio_device
+ * index: the 0-based virtqueue number in case there's more than one.
* callback: the virqtueue callback
- * Returns the new virtqueue or ERR_PTR().
+ * Returns the new virtqueue or ERR_PTR() (eg. -ENOENT).
* @del_vq: free a virtqueue found by find_vq().
*/
struct virtio_config_ops
{
- void *(*find)(struct virtio_device *vdev, u8 type, unsigned *len);
- void (*get)(struct virtio_device *vdev, void *token,
+ bool (*feature)(struct virtio_device *vdev, unsigned bit);
+ void (*get)(struct virtio_device *vdev, unsigned offset,
void *buf, unsigned len);
- void (*set)(struct virtio_device *vdev, void *token,
+ void (*set)(struct virtio_device *vdev, unsigned offset,
const void *buf, unsigned len);
u8 (*get_status)(struct virtio_device *vdev);
void (*set_status)(struct virtio_device *vdev, u8 status);
struct virtqueue *(*find_vq)(struct virtio_device *vdev,
+ unsigned index,
bool (*callback)(struct virtqueue *));
void (*del_vq)(struct virtqueue *vq);
};
/**
- * virtio_config_val - get a single virtio config and mark it used.
- * @config: the virtio config space
- * @type: the type to search for.
+ * virtio_config_val - look for a feature and get a single virtio config.
+ * @vdev: the virtio device
+ * @fbit: the feature bit
+ * @offset: the type to search for.
* @val: a pointer to the value to fill in.
*
- * Once used, the config type is marked with VIRTIO_CONFIG_F_USED so it
can't
- * be found again. This version does endian conversion. */
-#define virtio_config_val(vdev, type, v) ({ \
- int _err = __virtio_config_val((vdev),(type),(v),sizeof(*(v))); \
- \
- BUILD_BUG_ON(sizeof(*(v)) != 1 && sizeof(*(v)) != 2 \
- && sizeof(*(v)) != 4 && sizeof(*(v)) != 8); \
- if (!_err) { \
- 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; \
- } \
- } \
+ * 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; \
})
-int __virtio_config_val(struct virtio_device *dev,
- u8 type, void *val, size_t size);
-
/**
- * virtio_use_bit - helper to use a feature bit in a bitfield value.
- * @dev: the virtio device
- * @token: the token as returned from vdev->config->find().
- * @len: the length of the field.
- * @bitnum: the bit to test.
+ * __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.
*
- * If handed a NULL token, it returns false, otherwise returns bit status.
- * If it's one, it sets the mirroring acknowledgement bit. */
-int virtio_use_bit(struct virtio_device *vdev,
- void *token, unsigned int len, unsigned int bitnum);
+ * 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)
#endif /* __KERNEL__ */
#endif /* _LINUX_VIRTIO_CONFIG_H */
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index ae469ae..6e8fdfe 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -5,16 +5,19 @@
/* The ID for virtio_net */
#define VIRTIO_ID_NET 1
-/* The bitmap of config for virtio net */
-#define VIRTIO_CONFIG_NET_F 0x40
+/* The feature bitmap for virtio net */
#define VIRTIO_NET_F_NO_CSUM 0
#define VIRTIO_NET_F_TSO4 1
#define VIRTIO_NET_F_UFO 2
#define VIRTIO_NET_F_TSO4_ECN 3
#define VIRTIO_NET_F_TSO6 4
+#define VIRTIO_NET_F_MAC 5
-/* The config defining mac address. */
-#define VIRTIO_CONFIG_NET_MAC_F 0x41
+struct virtio_net_config
+{
+ /* The config defining mac address (if VIRTIO_NET_F_MAC) */
+ __u8 mac[6];
+} __attribute__((packed));
/* This is the first element of the scatter-gather list. If you don't
* specify GSO or CSUM features, you can simply ignore the header. */
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 40b71a2..78d7946 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -236,13 +236,13 @@ static int p9_virtio_probe(struct virtio_device *dev)
/* Find the input queue. */
dev->priv = chan;
- chan->in_vq = dev->config->find_vq(dev, p9_virtio_intr);
+ chan->in_vq = dev->config->find_vq(dev, 0, p9_virtio_intr);
if (IS_ERR(chan->in_vq)) {
err = PTR_ERR(chan->in_vq);
goto free;
}
- chan->out_vq = dev->config->find_vq(dev, NULL);
+ chan->out_vq = dev->config->find_vq(dev, 1, NULL);
if (IS_ERR(chan->out_vq)) {
err = PTR_ERR(chan->out_vq);
goto free_in_vq;
--
1.5.3.3
Apparently Analagous Threads
- [kvm-devel] [Virtio-for-kvm] [PATCH 1/13] [Mostly resend] virtio additions
- [PULL] virtio and lguest tree
- [PULL] virtio and lguest tree
- [PATCHv6 1/4] virtio: add names to virtqueue struct, mapping from devices to queues.
- [PATCHv6 1/4] virtio: add names to virtqueue struct, mapping from devices to queues.
Wisdom of the Ancients
