-/* They can register up to 32 arrays of lguest_dma. */
-#define LGUEST_MAX_DMA 32
-/* At most we can dma 16 lguest_dma in one op. */
-#define LGUEST_MAX_DMA_SECTIONS 16
-
-/* How many devices? Assume each one wants up to two dma arrays per device. */
-#define LGUEST_MAX_DEVICES (LGUEST_MAX_DMA/2)
-
-struct lguest_dma
-{
- /* 0 if free to be used, filled by hypervisor. */
- u32 used_len;
- unsigned long addr[LGUEST_MAX_DMA_SECTIONS];
- u16 len[LGUEST_MAX_DMA_SECTIONS];
-};
-
-struct lguest_block_page
-{
- /* 0 is a read, 1 is a write. */
- int type;
- u32 sector; /* Offset in device = sector * 512. */
- u32 bytes; /* Length expected to be read/written in bytes */
- /* 0 = pending, 1 = done, 2 = done, error */
- int result;
- u32 num_sectors; /* Disk length = num_sectors * 512 */
-};
-
-/* There is a shared page of these. */
-struct lguest_net
-{
- /* Simply the mac address (with multicast bit meaning promisc). */
- unsigned char mac[6];
-};
-
-/* Where the Host expects the Guest to SEND_DMA console output to. */
-#define LGUEST_CONSOLE_DMA_KEY 0
-
-/* We have a page of these descriptors in the lguest_device page. */
+#include <linux/types.h>
+
+/*D:010
+ * Drivers
+ *
+ * The Guest needs devices to do anything useful. Since we don't let it touch
+ * real devices (think of the damage it could do!) we provide virtual devices.
+ * We could emulate a PCI bus with various devices on it, but that is a fairly
+ * complex burden for the Host and suboptimal for the Guest, so we have our own
+ * simple lguest bus and we use "virtio" drivers. These drivers need a set of
+ * routines from us which will actually do the virtual I/O, but they handle all
+ * the net/block/console stuff themselves. This means that if we want to add
+ * a new device, we simply need to write a new virtio driver and create support
+ * for it in the Launcher: this code won't need to change.
+ *
+ * Devices are described by a simplified ID, a status byte, and some "config"
+ * bytes which describe this device's configuration. This is placed by the
+ * Launcher just above the top of physical memory:
+ */