summaryrefslogtreecommitdiff
path: root/target/i386/hax-mem.c
blob: 6bb5a249175cc9835625cdd4273cb86300a56d1d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
/*
 * HAX memory mapping operations
 *
 * Copyright (c) 2015-16 Intel Corporation
 * Copyright 2016 Google, Inc.
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 */

#include "qemu/osdep.h"
#include "cpu.h"
#include "exec/address-spaces.h"
#include "qemu/error-report.h"

#include "target/i386/hax-i386.h"
#include "qemu/queue.h"

#define DEBUG_HAX_MEM 0

#define DPRINTF(fmt, ...) \
    do { \
        if (DEBUG_HAX_MEM) { \
            fprintf(stdout, fmt, ## __VA_ARGS__); \
        } \
    } while (0)

/**
 * HAXMapping: describes a pending guest physical memory mapping
 *
 * @start_pa: a guest physical address marking the start of the region; must be
 *            page-aligned
 * @size: a guest physical address marking the end of the region; must be
 *          page-aligned
 * @host_va: the host virtual address of the start of the mapping
 * @flags: mapping parameters e.g. HAX_RAM_INFO_ROM or HAX_RAM_INFO_INVALID
 * @entry: additional fields for linking #HAXMapping instances together
 */
typedef struct HAXMapping {
    uint64_t start_pa;
    uint32_t size;
    uint64_t host_va;
    int flags;
    QTAILQ_ENTRY(HAXMapping) entry;
} HAXMapping;

/*
 * A doubly-linked list (actually a tail queue) of the pending page mappings
 * for the ongoing memory transaction.
 *
 * It is used to optimize the number of page mapping updates done through the
 * kernel module. For example, it's effective when a driver is digging an MMIO
 * hole inside an existing memory mapping. It will get a deletion of the whole
 * region, then the addition of the 2 remaining RAM areas around the hole and
 * finally the memory transaction commit. During the commit, it will effectively
 * send to the kernel only the removal of the pages from the MMIO hole after
 * having computed locally the result of the deletion and additions.
 */
static QTAILQ_HEAD(, HAXMapping) mappings =
    QTAILQ_HEAD_INITIALIZER(mappings);

/**
 * hax_mapping_dump_list: dumps @mappings to stdout (for debugging)
 */
static void hax_mapping_dump_list(void)
{
    HAXMapping *entry;

    DPRINTF("%s updates:\n", __func__);
    QTAILQ_FOREACH(entry, &mappings, entry) {
        DPRINTF("\t%c 0x%016" PRIx64 "->0x%016" PRIx64 " VA 0x%016" PRIx64
                "%s\n", entry->flags & HAX_RAM_INFO_INVALID ? '-' : '+',
                entry->start_pa, entry->start_pa + entry->size, entry->host_va,
                entry->flags & HAX_RAM_INFO_ROM ? " ROM" : "");
    }
}

static void hax_insert_mapping_before(HAXMapping *next, uint64_t start_pa,
                                      uint32_t size, uint64_t host_va,
                                      uint8_t flags)
{
    HAXMapping *entry;

    entry = g_malloc0(sizeof(*entry));
    entry->start_pa = start_pa;
    entry->size = size;
    entry->host_va = host_va;
    entry->flags = flags;
    if (!next) {
        QTAILQ_INSERT_TAIL(&mappings, entry, entry);
    } else {
        QTAILQ_INSERT_BEFORE(next, entry, entry);
    }
}

static bool hax_mapping_is_opposite(HAXMapping *entry, uint64_t host_va,
                                    uint8_t flags)
{
    /* removed then added without change for the read-only flag */
    bool nop_flags = (entry->flags ^ flags) == HAX_RAM_INFO_INVALID;

    return (entry->host_va == host_va) && nop_flags;
}

static void hax_update_mapping(uint64_t start_pa, uint32_t size,
                               uint64_t host_va, uint8_t flags)
{
    uint64_t end_pa = start_pa + size;
    HAXMapping *entry, *next;

    QTAILQ_FOREACH_SAFE(entry, &mappings, entry, next) {
        uint32_t chunk_sz;
        if (start_pa >= entry->start_pa + entry->size) {
            continue;
        }
        if (start_pa < entry->start_pa) {
            chunk_sz = end_pa <= entry->start_pa ? size
                                                 : entry->start_pa - start_pa;
            hax_insert_mapping_before(entry, start_pa, chunk_sz,
                                      host_va, flags);
            start_pa += chunk_sz;
            host_va += chunk_sz;
            size -= chunk_sz;
        } else if (start_pa > entry->start_pa) {
            /* split the existing chunk at start_pa */
            chunk_sz = start_pa - entry->start_pa;
            hax_insert_mapping_before(entry, entry->start_pa, chunk_sz,
                                      entry->host_va, entry->flags);
            entry->start_pa += chunk_sz;
            entry->host_va += chunk_sz;
            entry->size -= chunk_sz;
        }
        /* now start_pa == entry->start_pa */
        chunk_sz = MIN(size, entry->size);
        if (chunk_sz) {
            bool nop = hax_mapping_is_opposite(entry, host_va, flags);
            bool partial = chunk_sz < entry->size;
            if (partial) {
                /* remove the beginning of the existing chunk */
                entry->start_pa += chunk_sz;
                entry->host_va += chunk_sz;
                entry->size -= chunk_sz;
                if (!nop) {
                    hax_insert_mapping_before(entry, start_pa, chunk_sz,
                                              host_va, flags);
                }
            } else { /* affects the full mapping entry */
                if (nop) { /* no change to this mapping, remove it */
                    QTAILQ_REMOVE(&mappings, entry, entry);
                    g_free(entry);
                } else { /* update mapping properties */
                    entry->host_va = host_va;
                    entry->flags = flags;
                }
            }
            start_pa += chunk_sz;
            host_va += chunk_sz;
            size -= chunk_sz;
        }
        if (!size) { /* we are done */
            break;
        }
    }
    if (size) { /* add the leftover */
        hax_insert_mapping_before(NULL, start_pa, size, host_va, flags);
    }
}

static void hax_process_section(MemoryRegionSection *section, uint8_t flags)
{
    MemoryRegion *mr = section->mr;
    hwaddr start_pa = section->offset_within_address_space;
    ram_addr_t size = int128_get64(section->size);
    unsigned int delta;
    uint64_t host_va;
    uint32_t max_mapping_size;

    /* We only care about RAM and ROM regions */
    if (!memory_region_is_ram(mr)) {
        if (memory_region_is_romd(mr)) {
            /* HAXM kernel module does not support ROMD yet  */
            warn_report("Ignoring ROMD region 0x%016" PRIx64 "->0x%016" PRIx64,
                        start_pa, start_pa + size);
        }
        return;
    }

    /* Adjust start_pa and size so that they are page-aligned. (Cf
     * kvm_set_phys_mem() in kvm-all.c).
     */
    delta = qemu_real_host_page_size - (start_pa & ~qemu_real_host_page_mask);
    delta &= ~qemu_real_host_page_mask;
    if (delta > size) {
        return;
    }
    start_pa += delta;
    size -= delta;
    size &= qemu_real_host_page_mask;
    if (!size || (start_pa & ~qemu_real_host_page_mask)) {
        return;
    }

    host_va = (uintptr_t)memory_region_get_ram_ptr(mr)
            + section->offset_within_region + delta;
    if (memory_region_is_rom(section->mr)) {
        flags |= HAX_RAM_INFO_ROM;
    }

    /*
     * The kernel module interface uses 32-bit sizes:
     * https://github.com/intel/haxm/blob/master/API.md#hax_vm_ioctl_set_ram
     *
     * If the mapping size is longer than 32 bits, we can't process it in one
     * call into the kernel. Instead, we split the mapping into smaller ones,
     * and call hax_update_mapping() on each.
     */
    max_mapping_size = UINT32_MAX & qemu_real_host_page_mask;
    while (size > max_mapping_size) {
        hax_update_mapping(start_pa, max_mapping_size, host_va, flags);
        start_pa += max_mapping_size;
        size -= max_mapping_size;
        host_va += max_mapping_size;
    }
    /* Now size <= max_mapping_size */
    hax_update_mapping(start_pa, (uint32_t)size, host_va, flags);
}

static void hax_region_add(MemoryListener *listener,
                           MemoryRegionSection *section)
{
    memory_region_ref(section->mr);
    hax_process_section(section, 0);
}

static void hax_region_del(MemoryListener *listener,
                           MemoryRegionSection *section)
{
    hax_process_section(section, HAX_RAM_INFO_INVALID);
    memory_region_unref(section->mr);
}

static void hax_transaction_begin(MemoryListener *listener)
{
    g_assert(QTAILQ_EMPTY(&mappings));
}

static void hax_transaction_commit(MemoryListener *listener)
{
    if (!QTAILQ_EMPTY(&mappings)) {
        HAXMapping *entry, *next;

        if (DEBUG_HAX_MEM) {
            hax_mapping_dump_list();
        }
        QTAILQ_FOREACH_SAFE(entry, &mappings, entry, next) {
            if (entry->flags & HAX_RAM_INFO_INVALID) {
                /* for unmapping, put the values expected by the kernel */
                entry->flags = HAX_RAM_INFO_INVALID;
                entry->host_va = 0;
            }
            if (hax_set_ram(entry->start_pa, entry->size,
                            entry->host_va, entry->flags)) {
                fprintf(stderr, "%s: Failed mapping @0x%016" PRIx64 "+0x%"
                        PRIx32 " flags %02x\n", __func__, entry->start_pa,
                        entry->size, entry->flags);
            }
            QTAILQ_REMOVE(&mappings, entry, entry);
            g_free(entry);
        }
    }
}

/* currently we fake the dirty bitmap sync, always dirty */
static void hax_log_sync(MemoryListener *listener,
                         MemoryRegionSection *section)
{
    MemoryRegion *mr = section->mr;

    if (!memory_region_is_ram(mr)) {
        /* Skip MMIO regions */
        return;
    }

    memory_region_set_dirty(mr, 0, int128_get64(section->size));
}

static MemoryListener hax_memory_listener = {
    .begin = hax_transaction_begin,
    .commit = hax_transaction_commit,
    .region_add = hax_region_add,
    .region_del = hax_region_del,
    .log_sync = hax_log_sync,
    .priority = 10,
};

static void hax_ram_block_added(RAMBlockNotifier *n, void *host, size_t size)
{
    /*
     * We must register each RAM block with the HAXM kernel module, or
     * hax_set_ram() will fail for any mapping into the RAM block:
     * https://github.com/intel/haxm/blob/master/API.md#hax_vm_ioctl_alloc_ram
     *
     * Old versions of the HAXM kernel module (< 6.2.0) used to preallocate all
     * host physical pages for the RAM block as part of this registration
     * process, hence the name hax_populate_ram().
     */
    if (hax_populate_ram((uint64_t)(uintptr_t)host, size) < 0) {
        fprintf(stderr, "HAX failed to populate RAM\n");
        abort();
    }
}

static struct RAMBlockNotifier hax_ram_notifier = {
    .ram_block_added = hax_ram_block_added,
};

void hax_memory_init(void)
{
    ram_block_notifier_add(&hax_ram_notifier);
    memory_listener_register(&hax_memory_listener, &address_space_memory);
}