xref: /qemu/hw/ppc/spapr_ovec.c (revision 6402cbbb) 
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 "qemu/bitmap.h"
17 #include "exec/address-spaces.h"
18 #include "qemu/error-report.h"
19 #include "trace.h"
20 #include <libfdt.h>
21 
22 #define OV_MAXBYTES 256 /* not including length byte */
23 #define OV_MAXBITS (OV_MAXBYTES * BITS_PER_BYTE)
24 
25 /* we *could* work with bitmaps directly, but handling the bitmap privately
26  * allows us to more safely make assumptions about the bitmap size and
27  * simplify the calling code somewhat
28  */
29 struct sPAPROptionVector {
30     unsigned long *bitmap;
31     int32_t bitmap_size; /* only used for migration */
32 };
33 
34 const VMStateDescription vmstate_spapr_ovec = {
35     .name = "spapr_option_vector",
36     .version_id = 1,
37     .minimum_version_id = 1,
38     .fields = (VMStateField[]) {
39         VMSTATE_BITMAP(bitmap, sPAPROptionVector, 1, bitmap_size),
40         VMSTATE_END_OF_LIST()
41     }
42 };
43 
44 sPAPROptionVector *spapr_ovec_new(void)
45 {
46     sPAPROptionVector *ov;
47 
48     ov = g_new0(sPAPROptionVector, 1);
49     ov->bitmap = bitmap_new(OV_MAXBITS);
50     ov->bitmap_size = OV_MAXBITS;
51 
52     return ov;
53 }
54 
55 sPAPROptionVector *spapr_ovec_clone(sPAPROptionVector *ov_orig)
56 {
57     sPAPROptionVector *ov;
58 
59     g_assert(ov_orig);
60 
61     ov = spapr_ovec_new();
62     bitmap_copy(ov->bitmap, ov_orig->bitmap, OV_MAXBITS);
63 
64     return ov;
65 }
66 
67 void spapr_ovec_intersect(sPAPROptionVector *ov,
68                           sPAPROptionVector *ov1,
69                           sPAPROptionVector *ov2)
70 {
71     g_assert(ov);
72     g_assert(ov1);
73     g_assert(ov2);
74 
75     bitmap_and(ov->bitmap, ov1->bitmap, ov2->bitmap, OV_MAXBITS);
76 }
77 
78 /* returns true if options bits were removed, false otherwise */
79 bool spapr_ovec_diff(sPAPROptionVector *ov,
80                      sPAPROptionVector *ov_old,
81                      sPAPROptionVector *ov_new)
82 {
83     unsigned long *change_mask = bitmap_new(OV_MAXBITS);
84     unsigned long *removed_bits = bitmap_new(OV_MAXBITS);
85     bool bits_were_removed = false;
86 
87     g_assert(ov);
88     g_assert(ov_old);
89     g_assert(ov_new);
90 
91     bitmap_xor(change_mask, ov_old->bitmap, ov_new->bitmap, OV_MAXBITS);
92     bitmap_and(ov->bitmap, ov_new->bitmap, change_mask, OV_MAXBITS);
93     bitmap_and(removed_bits, ov_old->bitmap, change_mask, OV_MAXBITS);
94 
95     if (!bitmap_empty(removed_bits, OV_MAXBITS)) {
96         bits_were_removed = true;
97     }
98 
99     g_free(change_mask);
100     g_free(removed_bits);
101 
102     return bits_were_removed;
103 }
104 
105 void spapr_ovec_cleanup(sPAPROptionVector *ov)
106 {
107     if (ov) {
108         g_free(ov->bitmap);
109         g_free(ov);
110     }
111 }
112 
113 void spapr_ovec_set(sPAPROptionVector *ov, long bitnr)
114 {
115     g_assert(ov);
116     g_assert_cmpint(bitnr, <, OV_MAXBITS);
117 
118     set_bit(bitnr, ov->bitmap);
119 }
120 
121 void spapr_ovec_clear(sPAPROptionVector *ov, long bitnr)
122 {
123     g_assert(ov);
124     g_assert_cmpint(bitnr, <, OV_MAXBITS);
125 
126     clear_bit(bitnr, ov->bitmap);
127 }
128 
129 bool spapr_ovec_test(sPAPROptionVector *ov, long bitnr)
130 {
131     g_assert(ov);
132     g_assert_cmpint(bitnr, <, OV_MAXBITS);
133 
134     return test_bit(bitnr, ov->bitmap) ? true : false;
135 }
136 
137 static void guest_byte_to_bitmap(uint8_t entry, unsigned long *bitmap,
138                                  long bitmap_offset)
139 {
140     int i;
141 
142     for (i = 0; i < BITS_PER_BYTE; i++) {
143         if (entry & (1 << (BITS_PER_BYTE - 1 - i))) {
144             bitmap_set(bitmap, bitmap_offset + i, 1);
145         }
146     }
147 }
148 
149 static uint8_t guest_byte_from_bitmap(unsigned long *bitmap, long bitmap_offset)
150 {
151     uint8_t entry = 0;
152     int i;
153 
154     for (i = 0; i < BITS_PER_BYTE; i++) {
155         if (test_bit(bitmap_offset + i, bitmap)) {
156             entry |= (1 << (BITS_PER_BYTE - 1 - i));
157         }
158     }
159 
160     return entry;
161 }
162 
163 static target_ulong vector_addr(target_ulong table_addr, int vector)
164 {
165     uint16_t vector_count, vector_len;
166     int i;
167 
168     vector_count = ldub_phys(&address_space_memory, table_addr) + 1;
169     if (vector > vector_count) {
170         return 0;
171     }
172     table_addr++; /* skip nr option vectors */
173 
174     for (i = 0; i < vector - 1; i++) {
175         vector_len = ldub_phys(&address_space_memory, table_addr) + 1;
176         table_addr += vector_len + 1; /* bit-vector + length byte */
177     }
178     return table_addr;
179 }
180 
181 sPAPROptionVector *spapr_ovec_parse_vector(target_ulong table_addr, int vector)
182 {
183     sPAPROptionVector *ov;
184     target_ulong addr;
185     uint16_t vector_len;
186     int i;
187 
188     g_assert(table_addr);
189     g_assert_cmpint(vector, >=, 1); /* vector numbering starts at 1 */
190 
191     addr = vector_addr(table_addr, vector);
192     if (!addr) {
193         /* specified vector isn't present */
194         return NULL;
195     }
196 
197     vector_len = ldub_phys(&address_space_memory, addr++) + 1;
198     g_assert_cmpint(vector_len, <=, OV_MAXBYTES);
199     ov = spapr_ovec_new();
200 
201     for (i = 0; i < vector_len; i++) {
202         uint8_t entry = ldub_phys(&address_space_memory, addr + i);
203         if (entry) {
204             trace_spapr_ovec_parse_vector(vector, i + 1, vector_len, entry);
205             guest_byte_to_bitmap(entry, ov->bitmap, i * BITS_PER_BYTE);
206         }
207     }
208 
209     return ov;
210 }
211 
212 int spapr_ovec_populate_dt(void *fdt, int fdt_offset,
213                            sPAPROptionVector *ov, const char *name)
214 {
215     uint8_t vec[OV_MAXBYTES + 1];
216     uint16_t vec_len;
217     unsigned long lastbit;
218     int i;
219 
220     g_assert(ov);
221 
222     lastbit = find_last_bit(ov->bitmap, OV_MAXBITS);
223     /* if no bits are set, include at least 1 byte of the vector so we can
224      * still encoded this in the device tree while abiding by the same
225      * encoding/sizing expected in ibm,client-architecture-support
226      */
227     vec_len = (lastbit == OV_MAXBITS) ? 1 : lastbit / BITS_PER_BYTE + 1;
228     g_assert_cmpint(vec_len, <=, OV_MAXBYTES);
229     /* guest expects vector len encoded as vec_len - 1, since the length byte
230      * is assumed and not included, and the first byte of the vector
231      * is assumed as well
232      */
233     vec[0] = vec_len - 1;
234 
235     for (i = 1; i < vec_len + 1; i++) {
236         vec[i] = guest_byte_from_bitmap(ov->bitmap, (i - 1) * BITS_PER_BYTE);
237         if (vec[i]) {
238             trace_spapr_ovec_populate_dt(i, vec_len, vec[i]);
239         }
240     }
241 
242     return fdt_setprop(fdt, fdt_offset, name, vec, vec_len + 1);
243 }
244