diff options
Diffstat (limited to 'include/linux/lguest_launcher.h')
-rw-r--r-- | include/linux/lguest_launcher.h | 36 |
1 files changed, 1 insertions, 35 deletions
diff --git a/include/linux/lguest_launcher.h b/include/linux/lguest_launcher.h index b6603f3fbff8..5ec04a225e4f 100644 --- a/include/linux/lguest_launcher.h +++ b/include/linux/lguest_launcher.h | |||
@@ -10,40 +10,6 @@ | |||
10 | /* How many devices? Assume each one wants up to two dma arrays per device. */ | 10 | /* How many devices? Assume each one wants up to two dma arrays per device. */ |
11 | #define LGUEST_MAX_DEVICES (LGUEST_MAX_DMA/2) | 11 | #define LGUEST_MAX_DEVICES (LGUEST_MAX_DMA/2) |
12 | 12 | ||
13 | /*D:200 | ||
14 | * Lguest I/O | ||
15 | * | ||
16 | * The lguest I/O mechanism is the only way Guests can talk to devices. There | ||
17 | * are two hypercalls involved: SEND_DMA for output and BIND_DMA for input. In | ||
18 | * each case, "struct lguest_dma" describes the buffer: this contains 16 | ||
19 | * addr/len pairs, and if there are fewer buffer elements the len array is | ||
20 | * terminated with a 0. | ||
21 | * | ||
22 | * I/O is organized by keys: BIND_DMA attaches buffers to a particular key, and | ||
23 | * SEND_DMA transfers to buffers bound to particular key. By convention, keys | ||
24 | * correspond to a physical address within the device's page. This means that | ||
25 | * devices will never accidentally end up with the same keys, and allows the | ||
26 | * Host use The Futex Trick (as we'll see later in our journey). | ||
27 | * | ||
28 | * SEND_DMA simply indicates a key to send to, and the physical address of the | ||
29 | * "struct lguest_dma" to send. The Host will write the number of bytes | ||
30 | * transferred into the "struct lguest_dma"'s used_len member. | ||
31 | * | ||
32 | * BIND_DMA indicates a key to bind to, a pointer to an array of "struct | ||
33 | * lguest_dma"s ready for receiving, the size of that array, and an interrupt | ||
34 | * to trigger when data is received. The Host will only allow transfers into | ||
35 | * buffers with a used_len of zero: it then sets used_len to the number of | ||
36 | * bytes transferred and triggers the interrupt for the Guest to process the | ||
37 | * new input. */ | ||
38 | struct lguest_dma | ||
39 | { | ||
40 | /* 0 if free to be used, filled by the Host. */ | ||
41 | __u32 used_len; | ||
42 | __u16 len[LGUEST_MAX_DMA_SECTIONS]; | ||
43 | unsigned long addr[LGUEST_MAX_DMA_SECTIONS]; | ||
44 | }; | ||
45 | /*:*/ | ||
46 | |||
47 | /* Where the Host expects the Guest to SEND_DMA console output to. */ | 13 | /* Where the Host expects the Guest to SEND_DMA console output to. */ |
48 | #define LGUEST_CONSOLE_DMA_KEY 0 | 14 | #define LGUEST_CONSOLE_DMA_KEY 0 |
49 | 15 | ||
@@ -95,7 +61,7 @@ struct lguest_device_desc { | |||
95 | enum lguest_req | 61 | enum lguest_req |
96 | { | 62 | { |
97 | LHREQ_INITIALIZE, /* + pfnlimit, pgdir, start, pageoffset */ | 63 | LHREQ_INITIALIZE, /* + pfnlimit, pgdir, start, pageoffset */ |
98 | LHREQ_GETDMA, /* + addr (returns &lguest_dma, irq in ->used_len) */ | 64 | LHREQ_GETDMA, /* No longer used */ |
99 | LHREQ_IRQ, /* + irq */ | 65 | LHREQ_IRQ, /* + irq */ |
100 | LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */ | 66 | LHREQ_BREAK, /* + on/off flag (on blocks until someone does off) */ |
101 | }; | 67 | }; |