* 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.
*
+ * Virtio devices are also used by kvm, so we can simply reuse their optimized
+ * device drivers. And one day when everyone uses virtio, my plan will be
+ * complete. Bwahahahah!
+ *
* 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:
struct lguest_device_desc {
/* The device type: console, network, disk etc. Type 0 terminates. */
__u8 type;
- /* The number of bytes of the config array. */
+ /* The number of virtqueues (first in config array) */
+ __u8 num_vq;
+ /* The number of bytes of feature bits. Multiply by 2: one for host
+ * features and one for Guest acknowledgements. */
+ __u8 feature_len;
+ /* The number of bytes of the config array after virtqueues. */
__u8 config_len;
/* A status byte, written by the Guest. */
__u8 status;
};
/*D:135 This is how we expect the device configuration field for a virtqueue
- * (type VIRTIO_CONFIG_F_VIRTQUEUE) to be laid out: */
+ * to be laid out in config space. */
struct lguest_vqconfig {
/* The number of entries in the virtio_ring */
__u16 num;
/* Write command first word is a request. */
enum lguest_req
{
- LHREQ_INITIALIZE, /* + base, pfnlimit, pgdir, start */
+ LHREQ_INITIALIZE, /* + base, pfnlimit, start */
LHREQ_GETDMA, /* No longer used */
LHREQ_IRQ, /* + irq */
LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */
};
+
+/* The alignment to use between consumer and producer parts of vring.
+ * x86 pagesize for historical reasons. */
+#define LGUEST_VRING_ALIGN 4096
#endif /* _LINUX_LGUEST_LAUNCHER */