1 /*
2 * DMA helper functions
3 *
4 * Copyright (c) 2009 Red Hat
5 *
6 * This work is licensed under the terms of the GNU General Public License
7 * (GNU GPL), version 2 or later.
8 */
9
10 #include "dma.h"
11 #include "block_int.h"
12
qemu_sglist_init(QEMUSGList * qsg,int alloc_hint)13 void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint)
14 {
15 qsg->sg = qemu_malloc(alloc_hint * sizeof(ScatterGatherEntry));
16 qsg->nsg = 0;
17 qsg->nalloc = alloc_hint;
18 qsg->size = 0;
19 }
20
qemu_sglist_add(QEMUSGList * qsg,target_phys_addr_t base,target_phys_addr_t len)21 void qemu_sglist_add(QEMUSGList *qsg, target_phys_addr_t base,
22 target_phys_addr_t len)
23 {
24 if (qsg->nsg == qsg->nalloc) {
25 qsg->nalloc = 2 * qsg->nalloc + 1;
26 qsg->sg = qemu_realloc(qsg->sg, qsg->nalloc * sizeof(ScatterGatherEntry));
27 }
28 qsg->sg[qsg->nsg].base = base;
29 qsg->sg[qsg->nsg].len = len;
30 qsg->size += len;
31 ++qsg->nsg;
32 }
33
qemu_sglist_destroy(QEMUSGList * qsg)34 void qemu_sglist_destroy(QEMUSGList *qsg)
35 {
36 qemu_free(qsg->sg);
37 }
38
39 typedef struct {
40 BlockDriverAIOCB common;
41 BlockDriverState *bs;
42 BlockDriverAIOCB *acb;
43 QEMUSGList *sg;
44 uint64_t sector_num;
45 int is_write;
46 int sg_cur_index;
47 target_phys_addr_t sg_cur_byte;
48 QEMUIOVector iov;
49 QEMUBH *bh;
50 } DMAAIOCB;
51
52 static void dma_bdrv_cb(void *opaque, int ret);
53
reschedule_dma(void * opaque)54 static void reschedule_dma(void *opaque)
55 {
56 DMAAIOCB *dbs = (DMAAIOCB *)opaque;
57
58 qemu_bh_delete(dbs->bh);
59 dbs->bh = NULL;
60 dma_bdrv_cb(opaque, 0);
61 }
62
continue_after_map_failure(void * opaque)63 static void continue_after_map_failure(void *opaque)
64 {
65 DMAAIOCB *dbs = (DMAAIOCB *)opaque;
66
67 dbs->bh = qemu_bh_new(reschedule_dma, dbs);
68 qemu_bh_schedule(dbs->bh);
69 }
70
dma_bdrv_unmap(DMAAIOCB * dbs)71 static void dma_bdrv_unmap(DMAAIOCB *dbs)
72 {
73 int i;
74
75 for (i = 0; i < dbs->iov.niov; ++i) {
76 cpu_physical_memory_unmap(dbs->iov.iov[i].iov_base,
77 dbs->iov.iov[i].iov_len, !dbs->is_write,
78 dbs->iov.iov[i].iov_len);
79 }
80 }
81
dma_bdrv_cb(void * opaque,int ret)82 static void dma_bdrv_cb(void *opaque, int ret)
83 {
84 DMAAIOCB *dbs = (DMAAIOCB *)opaque;
85 target_phys_addr_t cur_addr, cur_len;
86 void *mem;
87
88 dbs->acb = NULL;
89 dbs->sector_num += dbs->iov.size / 512;
90 dma_bdrv_unmap(dbs);
91 qemu_iovec_reset(&dbs->iov);
92
93 if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
94 dbs->common.cb(dbs->common.opaque, ret);
95 qemu_iovec_destroy(&dbs->iov);
96 qemu_aio_release(dbs);
97 return;
98 }
99
100 while (dbs->sg_cur_index < dbs->sg->nsg) {
101 cur_addr = dbs->sg->sg[dbs->sg_cur_index].base + dbs->sg_cur_byte;
102 cur_len = dbs->sg->sg[dbs->sg_cur_index].len - dbs->sg_cur_byte;
103 mem = cpu_physical_memory_map(cur_addr, &cur_len, !dbs->is_write);
104 if (!mem)
105 break;
106 qemu_iovec_add(&dbs->iov, mem, cur_len);
107 dbs->sg_cur_byte += cur_len;
108 if (dbs->sg_cur_byte == dbs->sg->sg[dbs->sg_cur_index].len) {
109 dbs->sg_cur_byte = 0;
110 ++dbs->sg_cur_index;
111 }
112 }
113
114 if (dbs->iov.size == 0) {
115 cpu_register_map_client(dbs, continue_after_map_failure);
116 return;
117 }
118
119 if (dbs->is_write) {
120 dbs->acb = bdrv_aio_writev(dbs->bs, dbs->sector_num, &dbs->iov,
121 dbs->iov.size / 512, dma_bdrv_cb, dbs);
122 } else {
123 dbs->acb = bdrv_aio_readv(dbs->bs, dbs->sector_num, &dbs->iov,
124 dbs->iov.size / 512, dma_bdrv_cb, dbs);
125 }
126 if (!dbs->acb) {
127 dma_bdrv_unmap(dbs);
128 qemu_iovec_destroy(&dbs->iov);
129 return;
130 }
131 }
132
dma_aio_cancel(BlockDriverAIOCB * acb)133 static void dma_aio_cancel(BlockDriverAIOCB *acb)
134 {
135 DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
136
137 if (dbs->acb) {
138 bdrv_aio_cancel(dbs->acb);
139 }
140 }
141
142 static AIOPool dma_aio_pool = {
143 .aiocb_size = sizeof(DMAAIOCB),
144 .cancel = dma_aio_cancel,
145 };
146
dma_bdrv_io(BlockDriverState * bs,QEMUSGList * sg,uint64_t sector_num,BlockDriverCompletionFunc * cb,void * opaque,int is_write)147 static BlockDriverAIOCB *dma_bdrv_io(
148 BlockDriverState *bs, QEMUSGList *sg, uint64_t sector_num,
149 BlockDriverCompletionFunc *cb, void *opaque,
150 int is_write)
151 {
152 DMAAIOCB *dbs = qemu_aio_get(&dma_aio_pool, bs, cb, opaque);
153
154 dbs->acb = NULL;
155 dbs->bs = bs;
156 dbs->sg = sg;
157 dbs->sector_num = sector_num;
158 dbs->sg_cur_index = 0;
159 dbs->sg_cur_byte = 0;
160 dbs->is_write = is_write;
161 dbs->bh = NULL;
162 qemu_iovec_init(&dbs->iov, sg->nsg);
163 dma_bdrv_cb(dbs, 0);
164 if (!dbs->acb) {
165 qemu_aio_release(dbs);
166 return NULL;
167 }
168 return &dbs->common;
169 }
170
171
dma_bdrv_read(BlockDriverState * bs,QEMUSGList * sg,uint64_t sector,void (* cb)(void * opaque,int ret),void * opaque)172 BlockDriverAIOCB *dma_bdrv_read(BlockDriverState *bs,
173 QEMUSGList *sg, uint64_t sector,
174 void (*cb)(void *opaque, int ret), void *opaque)
175 {
176 return dma_bdrv_io(bs, sg, sector, cb, opaque, 0);
177 }
178
dma_bdrv_write(BlockDriverState * bs,QEMUSGList * sg,uint64_t sector,void (* cb)(void * opaque,int ret),void * opaque)179 BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs,
180 QEMUSGList *sg, uint64_t sector,
181 void (*cb)(void *opaque, int ret), void *opaque)
182 {
183 return dma_bdrv_io(bs, sg, sector, cb, opaque, 1);
184 }
185