xref: /openbmc/qemu/block/qed-table.c (revision 9f2130f58d5dd4e1fcb435cca08bf77e7c32e6c6)
1 /*
2  * QEMU Enhanced Disk Format Table I/O
3  *
4  * Copyright IBM, Corp. 2010
5  *
6  * Authors:
7  *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>
8  *  Anthony Liguori   <aliguori@us.ibm.com>
9  *
10  * This work is licensed under the terms of the GNU LGPL, version 2 or later.
11  * See the COPYING.LIB file in the top-level directory.
12  *
13  */
14 
15 #include "qemu/osdep.h"
16 #include "trace.h"
17 #include "qemu/sockets.h" /* for EINPROGRESS on Windows */
18 #include "qed.h"
19 #include "qemu/bswap.h"
20 
21 static int qed_read_table(BDRVQEDState *s, uint64_t offset, QEDTable *table)
22 {
23     QEMUIOVector qiov;
24     int noffsets;
25     int i, ret;
26 
27     struct iovec iov = {
28         .iov_base = table->offsets,
29         .iov_len = s->header.cluster_size * s->header.table_size,
30     };
31     qemu_iovec_init_external(&qiov, &iov, 1);
32 
33     trace_qed_read_table(s, offset, table);
34 
35     ret = bdrv_preadv(s->bs->file, offset, &qiov);
36     if (ret < 0) {
37         goto out;
38     }
39 
40     /* Byteswap offsets */
41     qed_acquire(s);
42     noffsets = qiov.size / sizeof(uint64_t);
43     for (i = 0; i < noffsets; i++) {
44         table->offsets[i] = le64_to_cpu(table->offsets[i]);
45     }
46     qed_release(s);
47 
48     ret = 0;
49 out:
50     /* Completion */
51     trace_qed_read_table_cb(s, table, ret);
52     return ret;
53 }
54 
55 /**
56  * Write out an updated part or all of a table
57  *
58  * @s:          QED state
59  * @offset:     Offset of table in image file, in bytes
60  * @table:      Table
61  * @index:      Index of first element
62  * @n:          Number of elements
63  * @flush:      Whether or not to sync to disk
64  */
65 static int qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
66                            unsigned int index, unsigned int n, bool flush)
67 {
68     unsigned int sector_mask = BDRV_SECTOR_SIZE / sizeof(uint64_t) - 1;
69     unsigned int start, end, i;
70     QEDTable *new_table;
71     struct iovec iov;
72     QEMUIOVector qiov;
73     size_t len_bytes;
74     int ret;
75 
76     trace_qed_write_table(s, offset, table, index, n);
77 
78     /* Calculate indices of the first and one after last elements */
79     start = index & ~sector_mask;
80     end = (index + n + sector_mask) & ~sector_mask;
81 
82     len_bytes = (end - start) * sizeof(uint64_t);
83 
84     new_table = qemu_blockalign(s->bs, len_bytes);
85     iov = (struct iovec) {
86         .iov_base = new_table->offsets,
87         .iov_len = len_bytes,
88     };
89     qemu_iovec_init_external(&qiov, &iov, 1);
90 
91     /* Byteswap table */
92     for (i = start; i < end; i++) {
93         uint64_t le_offset = cpu_to_le64(table->offsets[i]);
94         new_table->offsets[i - start] = le_offset;
95     }
96 
97     /* Adjust for offset into table */
98     offset += start * sizeof(uint64_t);
99 
100     ret = bdrv_pwritev(s->bs->file, offset, &qiov);
101     trace_qed_write_table_cb(s, table, flush, ret);
102     if (ret < 0) {
103         goto out;
104     }
105 
106     if (flush) {
107         qed_acquire(s);
108         ret = bdrv_flush(s->bs);
109         qed_release(s);
110         if (ret < 0) {
111             goto out;
112         }
113     }
114 
115     ret = 0;
116 out:
117     qemu_vfree(new_table);
118     return ret;
119 }
120 
121 int qed_read_l1_table_sync(BDRVQEDState *s)
122 {
123     return qed_read_table(s, s->header.l1_table_offset, s->l1_table);
124 }
125 
126 int qed_write_l1_table(BDRVQEDState *s, unsigned int index, unsigned int n)
127 {
128     BLKDBG_EVENT(s->bs->file, BLKDBG_L1_UPDATE);
129     return qed_write_table(s, s->header.l1_table_offset,
130                            s->l1_table, index, n, false);
131 }
132 
133 int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index,
134                             unsigned int n)
135 {
136     return qed_write_l1_table(s, index, n);
137 }
138 
139 int qed_read_l2_table(BDRVQEDState *s, QEDRequest *request, uint64_t offset)
140 {
141     int ret;
142 
143     qed_unref_l2_cache_entry(request->l2_table);
144 
145     /* Check for cached L2 entry */
146     request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);
147     if (request->l2_table) {
148         return 0;
149     }
150 
151     request->l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);
152     request->l2_table->table = qed_alloc_table(s);
153 
154     BLKDBG_EVENT(s->bs->file, BLKDBG_L2_LOAD);
155     ret = qed_read_table(s, offset, request->l2_table->table);
156 
157     qed_acquire(s);
158     if (ret) {
159         /* can't trust loaded L2 table anymore */
160         qed_unref_l2_cache_entry(request->l2_table);
161         request->l2_table = NULL;
162     } else {
163         request->l2_table->offset = offset;
164 
165         qed_commit_l2_cache_entry(&s->l2_cache, request->l2_table);
166 
167         /* This is guaranteed to succeed because we just committed the entry
168          * to the cache.
169          */
170         request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);
171         assert(request->l2_table != NULL);
172     }
173     qed_release(s);
174 
175     return ret;
176 }
177 
178 int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request, uint64_t offset)
179 {
180     return qed_read_l2_table(s, request, offset);
181 }
182 
183 int qed_write_l2_table(BDRVQEDState *s, QEDRequest *request,
184                        unsigned int index, unsigned int n, bool flush)
185 {
186     BLKDBG_EVENT(s->bs->file, BLKDBG_L2_UPDATE);
187     return qed_write_table(s, request->l2_table->offset,
188                            request->l2_table->table, index, n, flush);
189 }
190 
191 int qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request,
192                             unsigned int index, unsigned int n, bool flush)
193 {
194     return qed_write_l2_table(s, request, index, n, flush);
195 }
196