Commit a007a751 authored by Rusty Russell's avatar Rusty Russell
Browse files

lguest: make Launcher see device status updates 



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: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 9f3f7467

Documentation/lguest/lguest.c

+35 −15
Original line number Diff line number Diff line
@@ -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;

};
@@ -925,14 +928,14 @@ 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;



	/* This is a reset. */

	if (dev->desc->status == 0) {

		verbose("Resetting device %s\n", dev->name);

	/* Clear the status. */

	dev->desc->status = 0;



		/* Clear any features they've acked. */

		memset(get_feature_bits(dev) + dev->desc->feature_len, 0,
@@ -944,6 +947,22 @@ static void reset_device(struct device *dev) 
			       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);

	}

}



/* This is the generic routine we call when the Guest uses LHCALL_NOTIFY. */
@@ -954,9 +973,9 @@ 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;

		}
@@ -1170,6 +1189,7 @@ 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

drivers/lguest/lguest_device.c

+13 −7
Original line number Diff line number Diff line
@@ -144,20 +144,26 @@ static u8 lg_get_status(struct virtio_device *vdev) 
	return to_lgdev(vdev)->desc->status;

}



/* To notify on status updates, we (ab)use the NOTIFY hypercall, with the

 * descriptor address of the device.  A zero status means "reset". */

static void set_status(struct virtio_device *vdev, u8 status)

{

	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);

}



static void lg_set_status(struct virtio_device *vdev, u8 status)

{

	BUG_ON(!status);

	to_lgdev(vdev)->desc->status = status;

	set_status(vdev, 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;



	hcall(LHCALL_NOTIFY, (max_pfn<<PAGE_SHIFT) + offset, 0, 0);

	set_status(vdev, 0);

}



/*