summaryrefslogtreecommitdiffstats
path: root/Documentation/lguest/lguest.c
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/lguest/lguest.c')
-rw-r--r--Documentation/lguest/lguest.c74
1 files changed, 51 insertions, 23 deletions
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index 4c1fc65a8b3..82fafe0429f 100644
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -131,6 +131,9 @@ struct device
/* Any queues attached to this device */
struct virtqueue *vq;
+ /* Handle status being finalized (ie. feature bits stable). */
+ void (*ready)(struct device *me);
+
/* Device-specific data. */
void *priv;
};
@@ -154,6 +157,9 @@ struct virtqueue
/* The routine to call when the Guest pings us. */
void (*handle_output)(int fd, struct virtqueue *me);
+
+ /* Outstanding buffers */
+ unsigned int inflight;
};
/* Remember the arguments to the program so we can "reboot" */
@@ -699,6 +705,7 @@ static unsigned get_vq_desc(struct virtqueue *vq,
errx(1, "Looped descriptor");
} while ((i = next_desc(vq, i)) != vq->vring.num);
+ vq->inflight++;
return head;
}
@@ -716,6 +723,7 @@ static void add_used(struct virtqueue *vq, unsigned int head, int len)
/* Make sure buffer is written before we update index. */
wmb();
vq->vring.used->idx++;
+ vq->inflight--;
}
/* This actually sends the interrupt for this virtqueue */
@@ -723,8 +731,9 @@ static void trigger_irq(int fd, struct virtqueue *vq)
{
unsigned long buf[] = { LHREQ_IRQ, vq->config.irq };
- /* If they don't want an interrupt, don't send one. */
- if (vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
+ /* If they don't want an interrupt, don't send one, unless empty. */
+ if ((vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
+ && vq->inflight)
return;
/* Send the Guest an interrupt tell them we used something up. */
@@ -925,24 +934,40 @@ static void enable_fd(int fd, struct virtqueue *vq)
write(waker_fd, &vq->dev->fd, sizeof(vq->dev->fd));
}
-/* When the Guest asks us to reset a device, it's is fairly easy. */
-static void reset_device(struct device *dev)
+/* When the Guest tells us they updated the status field, we handle it. */
+static void update_device_status(struct device *dev)
{
struct virtqueue *vq;
- verbose("Resetting device %s\n", dev->name);
- /* Clear the status. */
- dev->desc->status = 0;
+ /* This is a reset. */
+ if (dev->desc->status == 0) {
+ verbose("Resetting device %s\n", dev->name);
- /* Clear any features they've acked. */
- memset(get_feature_bits(dev) + dev->desc->feature_len, 0,
- dev->desc->feature_len);
+ /* Clear any features they've acked. */
+ memset(get_feature_bits(dev) + dev->desc->feature_len, 0,
+ dev->desc->feature_len);
- /* Zero out the virtqueues. */
- for (vq = dev->vq; vq; vq = vq->next) {
- memset(vq->vring.desc, 0,
- vring_size(vq->config.num, getpagesize()));
- vq->last_avail_idx = 0;
+ /* Zero out the virtqueues. */
+ for (vq = dev->vq; vq; vq = vq->next) {
+ memset(vq->vring.desc, 0,
+ vring_size(vq->config.num, getpagesize()));
+ vq->last_avail_idx = 0;
+ }
+ } else if (dev->desc->status & VIRTIO_CONFIG_S_FAILED) {
+ warnx("Device %s configuration FAILED", dev->name);
+ } else if (dev->desc->status & VIRTIO_CONFIG_S_DRIVER_OK) {
+ unsigned int i;
+
+ verbose("Device %s OK: offered", dev->name);
+ for (i = 0; i < dev->desc->feature_len; i++)
+ verbose(" %08x", get_feature_bits(dev)[i]);
+ verbose(", accepted");
+ for (i = 0; i < dev->desc->feature_len; i++)
+ verbose(" %08x", get_feature_bits(dev)
+ [dev->desc->feature_len+i]);
+
+ if (dev->ready)
+ dev->ready(dev);
}
}
@@ -954,9 +979,9 @@ static void handle_output(int fd, unsigned long addr)
/* Check each device and virtqueue. */
for (i = devices.dev; i; i = i->next) {
- /* Notifications to device descriptors reset the device. */
+ /* Notifications to device descriptors update device status. */
if (from_guest_phys(addr) == i->desc) {
- reset_device(i);
+ update_device_status(i);
return;
}
@@ -1088,6 +1113,7 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
vq->next = NULL;
vq->last_avail_idx = 0;
vq->dev = dev;
+ vq->inflight = 0;
/* Initialize the configuration. */
vq->config.num = num_descs;
@@ -1170,6 +1196,7 @@ static struct device *new_device(const char *name, u16 type, int fd,
dev->handle_input = handle_input;
dev->name = name;
dev->vq = NULL;
+ dev->ready = 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
@@ -1348,6 +1375,7 @@ static void setup_tun_net(const char *arg)
/* Tell Guest what MAC address to use. */
add_feature(dev, VIRTIO_NET_F_MAC);
+ add_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY);
set_config(dev, sizeof(conf), &conf);
/* We don't need the socket any more; setup is done. */
@@ -1398,7 +1426,7 @@ static bool service_io(struct device *dev)
struct vblk_info *vblk = dev->priv;
unsigned int head, out_num, in_num, wlen;
int ret;
- struct virtio_blk_inhdr *in;
+ u8 *in;
struct virtio_blk_outhdr *out;
struct iovec iov[dev->vq->vring.num];
off64_t off;
@@ -1416,7 +1444,7 @@ static bool service_io(struct device *dev)
head, out_num, in_num);
out = convert(&iov[0], struct virtio_blk_outhdr);
- in = convert(&iov[out_num+in_num-1], struct virtio_blk_inhdr);
+ in = convert(&iov[out_num+in_num-1], u8);
off = out->sector * 512;
/* The block device implements "barriers", where the Guest indicates
@@ -1430,7 +1458,7 @@ static bool service_io(struct device *dev)
* It'd be nice if we supported eject, for example, but we don't. */
if (out->type & VIRTIO_BLK_T_SCSI_CMD) {
fprintf(stderr, "Scsi commands unsupported\n");
- in->status = VIRTIO_BLK_S_UNSUPP;
+ *in = VIRTIO_BLK_S_UNSUPP;
wlen = sizeof(*in);
} else if (out->type & VIRTIO_BLK_T_OUT) {
/* Write */
@@ -1453,7 +1481,7 @@ static bool service_io(struct device *dev)
errx(1, "Write past end %llu+%u", off, ret);
}
wlen = sizeof(*in);
- in->status = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);
+ *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);
} else {
/* Read */
@@ -1466,10 +1494,10 @@ static bool service_io(struct device *dev)
verbose("READ from sector %llu: %i\n", out->sector, ret);
if (ret >= 0) {
wlen = sizeof(*in) + ret;
- in->status = VIRTIO_BLK_S_OK;
+ *in = VIRTIO_BLK_S_OK;
} else {
wlen = sizeof(*in);
- in->status = VIRTIO_BLK_S_IOERR;
+ *in = VIRTIO_BLK_S_IOERR;
}
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-27 08:15:24 +0000