xref: /openbmc/qemu/block/qed-table.c (revision 64a917d5)
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 "block/block-io.h"
17  #include "trace.h"
18  #include "qemu/sockets.h" /* for EINPROGRESS on Windows */
19  #include "qed.h"
20  #include "qemu/bswap.h"
21  #include "qemu/memalign.h"
22  
23  /* Called with table_lock held.  */
24  static int coroutine_fn GRAPH_RDLOCK
25  qed_read_table(BDRVQEDState *s, uint64_t offset, QEDTable *table)
26  {
27      unsigned int bytes = s->header.cluster_size * s->header.table_size;
28  
29      int noffsets;
30      int i, ret;
31  
32      trace_qed_read_table(s, offset, table);
33  
34      qemu_co_mutex_unlock(&s->table_lock);
35      ret = bdrv_co_pread(s->bs->file, offset, bytes, table->offsets, 0);
36      qemu_co_mutex_lock(&s->table_lock);
37      if (ret < 0) {
38          goto out;
39      }
40  
41      /* Byteswap offsets */
42      noffsets = bytes / sizeof(uint64_t);
43      for (i = 0; i < noffsets; i++) {
44          table->offsets[i] = le64_to_cpu(table->offsets[i]);
45      }
46  
47      ret = 0;
48  out:
49      /* Completion */
50      trace_qed_read_table_cb(s, table, ret);
51      return ret;
52  }
53  
54  /**
55   * Write out an updated part or all of a table
56   *
57   * @s:          QED state
58   * @offset:     Offset of table in image file, in bytes
59   * @table:      Table
60   * @index:      Index of first element
61   * @n:          Number of elements
62   * @flush:      Whether or not to sync to disk
63   *
64   * Called with table_lock held.
65   */
66  static int coroutine_fn GRAPH_RDLOCK
67  qed_write_table(BDRVQEDState *s, uint64_t offset, QEDTable *table,
68                  unsigned int index, unsigned int n, bool flush)
69  {
70      unsigned int sector_mask = BDRV_SECTOR_SIZE / sizeof(uint64_t) - 1;
71      unsigned int start, end, i;
72      QEDTable *new_table;
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  
86      /* Byteswap table */
87      for (i = start; i < end; i++) {
88          uint64_t le_offset = cpu_to_le64(table->offsets[i]);
89          new_table->offsets[i - start] = le_offset;
90      }
91  
92      /* Adjust for offset into table */
93      offset += start * sizeof(uint64_t);
94  
95      qemu_co_mutex_unlock(&s->table_lock);
96      ret = bdrv_co_pwrite(s->bs->file, offset, len_bytes, new_table->offsets, 0);
97      qemu_co_mutex_lock(&s->table_lock);
98      trace_qed_write_table_cb(s, table, flush, ret);
99      if (ret < 0) {
100          goto out;
101      }
102  
103      if (flush) {
104          ret = bdrv_co_flush(s->bs);
105          if (ret < 0) {
106              goto out;
107          }
108      }
109  
110      ret = 0;
111  out:
112      qemu_vfree(new_table);
113      return ret;
114  }
115  
116  int coroutine_fn qed_read_l1_table_sync(BDRVQEDState *s)
117  {
118      return qed_read_table(s, s->header.l1_table_offset, s->l1_table);
119  }
120  
121  /* Called with table_lock held.  */
122  int coroutine_fn qed_write_l1_table(BDRVQEDState *s, unsigned int index,
123                                      unsigned int n)
124  {
125      BLKDBG_CO_EVENT(s->bs->file, BLKDBG_L1_UPDATE);
126      return qed_write_table(s, s->header.l1_table_offset,
127                             s->l1_table, index, n, false);
128  }
129  
130  int coroutine_fn qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index,
131                                           unsigned int n)
132  {
133      return qed_write_l1_table(s, index, n);
134  }
135  
136  /* Called with table_lock held.  */
137  int coroutine_fn qed_read_l2_table(BDRVQEDState *s, QEDRequest *request,
138                                     uint64_t offset)
139  {
140      int ret;
141  
142      qed_unref_l2_cache_entry(request->l2_table);
143  
144      /* Check for cached L2 entry */
145      request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);
146      if (request->l2_table) {
147          return 0;
148      }
149  
150      request->l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);
151      request->l2_table->table = qed_alloc_table(s);
152  
153      BLKDBG_CO_EVENT(s->bs->file, BLKDBG_L2_LOAD);
154      ret = qed_read_table(s, offset, request->l2_table->table);
155  
156      if (ret) {
157          /* can't trust loaded L2 table anymore */
158          qed_unref_l2_cache_entry(request->l2_table);
159          request->l2_table = NULL;
160      } else {
161          request->l2_table->offset = offset;
162  
163          qed_commit_l2_cache_entry(&s->l2_cache, request->l2_table);
164  
165          /* This is guaranteed to succeed because we just committed the entry
166           * to the cache.
167           */
168          request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, offset);
169          assert(request->l2_table != NULL);
170      }
171  
172      return ret;
173  }
174  
175  int coroutine_fn qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request,
176                                          uint64_t offset)
177  {
178      return qed_read_l2_table(s, request, offset);
179  }
180  
181  /* Called with table_lock held.  */
182  int coroutine_fn qed_write_l2_table(BDRVQEDState *s, QEDRequest *request,
183                                      unsigned int index, unsigned int n,
184                                      bool flush)
185  {
186      BLKDBG_CO_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 coroutine_fn qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request,
192                                           unsigned int index, unsigned int n,
193                                           bool flush)
194  {
195      return qed_write_l2_table(s, request, index, n, flush);
196  }
197