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lguest: make Launcher see device status updates

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This brings us closer to Real Life, where we'd examine the device
features once it's set the DRIVER_OK status bit.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2008-05-02 21:50:53 -05:00
parent 9f3f746741
commit a007a751d9
2 changed files with 51 additions and 25 deletions
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50
Documentation/lguest/lguest.c
View file

@ -131,6 +131,9 @@ struct device
/* Any queues attached to this device */ /* Any queues attached to this device */
struct virtqueue *vq; struct virtqueue *vq;
/* Handle status being finalized (ie. feature bits stable). */
void (*ready)(struct device *me);
/* Device-specific data. */ /* Device-specific data. */
void *priv; void *priv;
}; };
@ -925,24 +928,40 @@ static void enable_fd(int fd, struct virtqueue *vq)
write(waker_fd, &vq->dev->fd, sizeof(vq->dev->fd)); write(waker_fd, &vq->dev->fd, sizeof(vq->dev->fd));
} }
/* When the Guest asks us to reset a device, it's is fairly easy. */ /* When the Guest tells us they updated the status field, we handle it. */
static void reset_device(struct device *dev) static void update_device_status(struct device *dev)
{ {
struct virtqueue *vq; struct virtqueue *vq;
verbose("Resetting device %s\n", dev->name); /* This is a reset. */
/* Clear the status. */ if (dev->desc->status == 0) {
dev->desc->status = 0; verbose("Resetting device %s\n", dev->name);
/* Clear any features they've acked. */ /* Clear any features they've acked. */
memset(get_feature_bits(dev) + dev->desc->feature_len, 0, memset(get_feature_bits(dev) + dev->desc->feature_len, 0,
dev->desc->feature_len); dev->desc->feature_len);
/* Zero out the virtqueues. */ /* Zero out the virtqueues. */
for (vq = dev->vq; vq; vq = vq->next) { for (vq = dev->vq; vq; vq = vq->next) {
memset(vq->vring.desc, 0, memset(vq->vring.desc, 0,
vring_size(vq->config.num, getpagesize())); vring_size(vq->config.num, getpagesize()));
vq->last_avail_idx = 0; 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 +973,9 @@ static void handle_output(int fd, unsigned long addr)
/* Check each device and virtqueue. */ /* Check each device and virtqueue. */
for (i = devices.dev; i; i = i->next) { 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) { if (from_guest_phys(addr) == i->desc) {
reset_device(i); update_device_status(i);
return; return;
} }
@ -1170,6 +1189,7 @@ static struct device *new_device(const char *name, u16 type, int fd,
dev->handle_input = handle_input; dev->handle_input = handle_input;
dev->name = name; dev->name = name;
dev->vq = NULL; dev->vq = NULL;
dev->ready = NULL;
/* Append to device list. Prepending to a single-linked list is /* Append to device list. Prepending to a single-linked list is
* easier, but the user expects the devices to be arranged on the bus * easier, but the user expects the devices to be arranged on the bus

26
drivers/lguest/lguest_device.c
View file

@ -144,22 +144,28 @@ static u8 lg_get_status(struct virtio_device *vdev)
return to_lgdev(vdev)->desc->status; return to_lgdev(vdev)->desc->status;
} }
static void lg_set_status(struct virtio_device *vdev, u8 status) /* To notify on status updates, we (ab)use the NOTIFY hypercall, with the
{ * descriptor address of the device. A zero status means "reset". */
BUG_ON(!status); static void set_status(struct virtio_device *vdev, u8 status)
to_lgdev(vdev)->desc->status = status;
}
/* To reset the device, we (ab)use the NOTIFY hypercall, with the descriptor
* address of the device. The Host will zero the status and all the
* features. */
static void lg_reset(struct virtio_device *vdev)
{ {
unsigned long offset = (void *)to_lgdev(vdev)->desc - lguest_devices; unsigned long offset = (void *)to_lgdev(vdev)->desc - lguest_devices;
/* We set the status. */
to_lgdev(vdev)->desc->status = status;
hcall(LHCALL_NOTIFY, (max_pfn<<PAGE_SHIFT) + offset, 0, 0); hcall(LHCALL_NOTIFY, (max_pfn<<PAGE_SHIFT) + offset, 0, 0);
} }
static void lg_set_status(struct virtio_device *vdev, u8 status)
{
BUG_ON(!status);
set_status(vdev, status);
}
static void lg_reset(struct virtio_device *vdev)
{
set_status(vdev, 0);
}
/* /*
* Virtqueues * Virtqueues
* *