diff options
Diffstat (limited to 'drivers/lguest/lguest_device.c')
-rw-r--r-- | drivers/lguest/lguest_device.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c index 71c64837b437..8904f72f97c6 100644 --- a/drivers/lguest/lguest_device.c +++ b/drivers/lguest/lguest_device.c | |||
@@ -53,7 +53,8 @@ struct lguest_device { | |||
53 | * Device configurations | 53 | * Device configurations |
54 | * | 54 | * |
55 | * The configuration information for a device consists of a series of fields. | 55 | * The configuration information for a device consists of a series of fields. |
56 | * The device will look for these fields during setup. | 56 | * We don't really care what they are: the Launcher set them up, and the driver |
57 | * will look at them during setup. | ||
57 | * | 58 | * |
58 | * For us these fields come immediately after that device's descriptor in the | 59 | * For us these fields come immediately after that device's descriptor in the |
59 | * lguest_devices page. | 60 | * lguest_devices page. |
@@ -122,8 +123,8 @@ static void lg_set_status(struct virtio_device *vdev, u8 status) | |||
122 | * The other piece of infrastructure virtio needs is a "virtqueue": a way of | 123 | * The other piece of infrastructure virtio needs is a "virtqueue": a way of |
123 | * the Guest device registering buffers for the other side to read from or | 124 | * the Guest device registering buffers for the other side to read from or |
124 | * write into (ie. send and receive buffers). Each device can have multiple | 125 | * write into (ie. send and receive buffers). Each device can have multiple |
125 | * virtqueues: for example the console has one queue for sending and one for | 126 | * virtqueues: for example the console driver uses one queue for sending and |
126 | * receiving. | 127 | * another for receiving. |
127 | * | 128 | * |
128 | * Fortunately for us, a very fast shared-memory-plus-descriptors virtqueue | 129 | * Fortunately for us, a very fast shared-memory-plus-descriptors virtqueue |
129 | * already exists in virtio_ring.c. We just need to connect it up. | 130 | * already exists in virtio_ring.c. We just need to connect it up. |
@@ -158,7 +159,7 @@ static void lg_notify(struct virtqueue *vq) | |||
158 | * | 159 | * |
159 | * This is kind of an ugly duckling. It'd be nicer to have a standard | 160 | * This is kind of an ugly duckling. It'd be nicer to have a standard |
160 | * representation of a virtqueue in the configuration space, but it seems that | 161 | * representation of a virtqueue in the configuration space, but it seems that |
161 | * everyone wants to do it differently. The KVM guys want the Guest to | 162 | * everyone wants to do it differently. The KVM coders want the Guest to |
162 | * allocate its own pages and tell the Host where they are, but for lguest it's | 163 | * allocate its own pages and tell the Host where they are, but for lguest it's |
163 | * simpler for the Host to simply tell us where the pages are. | 164 | * simpler for the Host to simply tell us where the pages are. |
164 | * | 165 | * |
@@ -284,6 +285,8 @@ static void add_lguest_device(struct lguest_device_desc *d) | |||
284 | { | 285 | { |
285 | struct lguest_device *ldev; | 286 | struct lguest_device *ldev; |
286 | 287 | ||
288 | /* Start with zeroed memory; Linux's device layer seems to count on | ||
289 | * it. */ | ||
287 | ldev = kzalloc(sizeof(*ldev), GFP_KERNEL); | 290 | ldev = kzalloc(sizeof(*ldev), GFP_KERNEL); |
288 | if (!ldev) { | 291 | if (!ldev) { |
289 | printk(KERN_EMERG "Cannot allocate lguest dev %u\n", | 292 | printk(KERN_EMERG "Cannot allocate lguest dev %u\n", |