xref: /qemu/hw/ppc/spapr_ovec.c (revision e5b6353c) 
1 /*
2  * QEMU SPAPR Architecture Option Vector Helper Functions
3  *
4  * Copyright IBM Corp. 2016
5  *
6  * Authors:
7  *  Bharata B Rao     <bharata@linux.vnet.ibm.com>
8  *  Michael Roth      <mdroth@linux.vnet.ibm.com>
9  *
10  * This work is licensed under the terms of the GNU GPL, version 2 or later.
11  * See the COPYING file in the top-level directory.
12  */
13 
14 #include "qemu/osdep.h"
15 #include "hw/ppc/spapr_ovec.h"
16 #include "migration/vmstate.h"
17 #include "qemu/bitmap.h"
18 #include "exec/address-spaces.h"
19 #include "qemu/error-report.h"
20 #include "trace.h"
21 #include <libfdt.h>
22 
23 #define OV_MAXBYTES 256 /* not including length byte */
24 #define OV_MAXBITS (OV_MAXBYTES * BITS_PER_BYTE)
25 
26 /* we *could* work with bitmaps directly, but handling the bitmap privately
27  * allows us to more safely make assumptions about the bitmap size and
28  * simplify the calling code somewhat
29  */
30 struct SpaprOptionVector {
31     unsigned long *bitmap;
32     int32_t bitmap_size; /* only used for migration */
33 };
34 
35 const VMStateDescription vmstate_spapr_ovec = {
36     .name = "spapr_option_vector",
37     .version_id = 1,
38     .minimum_version_id = 1,
39     .fields = (VMStateField[]) {
40         VMSTATE_BITMAP(bitmap, SpaprOptionVector, 1, bitmap_size),
41         VMSTATE_END_OF_LIST()
42     }
43 };
44 
45 SpaprOptionVector *spapr_ovec_new(void)
46 {
47     SpaprOptionVector *ov;
48 
49     ov = g_new0(SpaprOptionVector, 1);
50     ov->bitmap = bitmap_new(OV_MAXBITS);
51     ov->bitmap_size = OV_MAXBITS;
52 
53     return ov;
54 }
55 
56 SpaprOptionVector *spapr_ovec_clone(SpaprOptionVector *ov_orig)
57 {
58     SpaprOptionVector *ov;
59 
60     g_assert(ov_orig);
61 
62     ov = spapr_ovec_new();
63     bitmap_copy(ov->bitmap, ov_orig->bitmap, OV_MAXBITS);
64 
65     return ov;
66 }
67 
68 void spapr_ovec_intersect(SpaprOptionVector *ov,
69                           SpaprOptionVector *ov1,
70                           SpaprOptionVector *ov2)
71 {
72     g_assert(ov);
73     g_assert(ov1);
74     g_assert(ov2);
75 
76     bitmap_and(ov->bitmap, ov1->bitmap, ov2->bitmap, OV_MAXBITS);
77 }
78 
79 /* returns true if options bits were removed, false otherwise */
80 bool spapr_ovec_diff(SpaprOptionVector *ov,
81                      SpaprOptionVector *ov_old,
82                      SpaprOptionVector *ov_new)
83 {
84     unsigned long *change_mask = bitmap_new(OV_MAXBITS);
85     unsigned long *removed_bits = bitmap_new(OV_MAXBITS);
86     bool bits_were_removed = false;
87 
88     g_assert(ov);
89     g_assert(ov_old);
90     g_assert(ov_new);
91 
92     bitmap_xor(change_mask, ov_old->bitmap, ov_new->bitmap, OV_MAXBITS);
93     bitmap_and(ov->bitmap, ov_new->bitmap, change_mask, OV_MAXBITS);
94     bitmap_and(removed_bits, ov_old->bitmap, change_mask, OV_MAXBITS);
95 
96     if (!bitmap_empty(removed_bits, OV_MAXBITS)) {
97         bits_were_removed = true;
98     }
99 
100     g_free(change_mask);
101     g_free(removed_bits);
102 
103     return bits_were_removed;
104 }
105 
106 void spapr_ovec_cleanup(SpaprOptionVector *ov)
107 {
108     if (ov) {
109         g_free(ov->bitmap);
110         g_free(ov);
111     }
112 }
113 
114 void spapr_ovec_set(SpaprOptionVector *ov, long bitnr)
115 {
116     g_assert(ov);
117     g_assert(bitnr < OV_MAXBITS);
118 
119     set_bit(bitnr, ov->bitmap);
120 }
121 
122 void spapr_ovec_clear(SpaprOptionVector *ov, long bitnr)
123 {
124     g_assert(ov);
125     g_assert(bitnr < OV_MAXBITS);
126 
127     clear_bit(bitnr, ov->bitmap);
128 }
129 
130 bool spapr_ovec_test(SpaprOptionVector *ov, long bitnr)
131 {
132     g_assert(ov);
133     g_assert(bitnr < OV_MAXBITS);
134 
135     return test_bit(bitnr, ov->bitmap) ? true : false;
136 }
137 
138 static void guest_byte_to_bitmap(uint8_t entry, unsigned long *bitmap,
139                                  long bitmap_offset)
140 {
141     int i;
142 
143     for (i = 0; i < BITS_PER_BYTE; i++) {
144         if (entry & (1 << (BITS_PER_BYTE - 1 - i))) {
145             bitmap_set(bitmap, bitmap_offset + i, 1);
146         }
147     }
148 }
149 
150 static uint8_t guest_byte_from_bitmap(unsigned long *bitmap, long bitmap_offset)
151 {
152     uint8_t entry = 0;
153     int i;
154 
155     for (i = 0; i < BITS_PER_BYTE; i++) {
156         if (test_bit(bitmap_offset + i, bitmap)) {
157             entry |= (1 << (BITS_PER_BYTE - 1 - i));
158         }
159     }
160 
161     return entry;
162 }
163 
164 static target_ulong vector_addr(target_ulong table_addr, int vector)
165 {
166     uint16_t vector_count, vector_len;
167     int i;
168 
169     vector_count = ldub_phys(&address_space_memory, table_addr) + 1;
170     if (vector > vector_count) {
171         return 0;
172     }
173     table_addr++; /* skip nr option vectors */
174 
175     for (i = 0; i < vector - 1; i++) {
176         vector_len = ldub_phys(&address_space_memory, table_addr) + 1;
177         table_addr += vector_len + 1; /* bit-vector + length byte */
178     }
179     return table_addr;
180 }
181 
182 SpaprOptionVector *spapr_ovec_parse_vector(target_ulong table_addr, int vector)
183 {
184     SpaprOptionVector *ov;
185     target_ulong addr;
186     uint16_t vector_len;
187     int i;
188 
189     g_assert(table_addr);
190     g_assert(vector >= 1);      /* vector numbering starts at 1 */
191 
192     addr = vector_addr(table_addr, vector);
193     if (!addr) {
194         /* specified vector isn't present */
195         return NULL;
196     }
197 
198     vector_len = ldub_phys(&address_space_memory, addr++) + 1;
199     g_assert(vector_len <= OV_MAXBYTES);
200     ov = spapr_ovec_new();
201 
202     for (i = 0; i < vector_len; i++) {
203         uint8_t entry = ldub_phys(&address_space_memory, addr + i);
204         if (entry) {
205             trace_spapr_ovec_parse_vector(vector, i + 1, vector_len, entry);
206             guest_byte_to_bitmap(entry, ov->bitmap, i * BITS_PER_BYTE);
207         }
208     }
209 
210     return ov;
211 }
212 
213 int spapr_ovec_populate_dt(void *fdt, int fdt_offset,
214                            SpaprOptionVector *ov, const char *name)
215 {
216     uint8_t vec[OV_MAXBYTES + 1];
217     uint16_t vec_len;
218     unsigned long lastbit;
219     int i;
220 
221     g_assert(ov);
222 
223     lastbit = find_last_bit(ov->bitmap, OV_MAXBITS);
224     /* if no bits are set, include at least 1 byte of the vector so we can
225      * still encoded this in the device tree while abiding by the same
226      * encoding/sizing expected in ibm,client-architecture-support
227      */
228     vec_len = (lastbit == OV_MAXBITS) ? 1 : lastbit / BITS_PER_BYTE + 1;
229     g_assert(vec_len <= OV_MAXBYTES);
230     /* guest expects vector len encoded as vec_len - 1, since the length byte
231      * is assumed and not included, and the first byte of the vector
232      * is assumed as well
233      */
234     vec[0] = vec_len - 1;
235 
236     for (i = 1; i < vec_len + 1; i++) {
237         vec[i] = guest_byte_from_bitmap(ov->bitmap, (i - 1) * BITS_PER_BYTE);
238         if (vec[i]) {
239             trace_spapr_ovec_populate_dt(i, vec_len, vec[i]);
240         }
241     }
242 
243     return fdt_setprop(fdt, fdt_offset, name, vec, vec_len + 1);
244 }
245