aboutsummaryrefslogtreecommitdiff
path: root/hw/dataplane/hostmem.c
blob: 37292ffd00ec83b24640a3a7c17536370844b5f2 (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
/*
 * Thread-safe guest to host memory mapping
 *
 * Copyright 2012 Red Hat, Inc. and/or its affiliates
 *
 * Authors:
 *   Stefan Hajnoczi <stefanha@redhat.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 *
 */

#include "exec/address-spaces.h"
#include "hw/virtio/dataplane/hostmem.h"

static int hostmem_lookup_cmp(const void *phys_, const void *region_)
{
    hwaddr phys = *(const hwaddr *)phys_;
    const HostMemRegion *region = region_;

    if (phys < region->guest_addr) {
        return -1;
    } else if (phys >= region->guest_addr + region->size) {
        return 1;
    } else {
        return 0;
    }
}

/**
 * Map guest physical address to host pointer
 */
void *hostmem_lookup(HostMem *hostmem, hwaddr phys, hwaddr len, bool is_write)
{
    HostMemRegion *region;
    void *host_addr = NULL;
    hwaddr offset_within_region;

    qemu_mutex_lock(&hostmem->current_regions_lock);
    region = bsearch(&phys, hostmem->current_regions,
                     hostmem->num_current_regions,
                     sizeof(hostmem->current_regions[0]),
                     hostmem_lookup_cmp);
    if (!region) {
        goto out;
    }
    if (is_write && region->readonly) {
        goto out;
    }
    offset_within_region = phys - region->guest_addr;
    if (len <= region->size - offset_within_region) {
        host_addr = region->host_addr + offset_within_region;
    }
out:
    qemu_mutex_unlock(&hostmem->current_regions_lock);

    return host_addr;
}

/**
 * Install new regions list
 */
static void hostmem_listener_commit(MemoryListener *listener)
{
    HostMem *hostmem = container_of(listener, HostMem, listener);

    qemu_mutex_lock(&hostmem->current_regions_lock);
    g_free(hostmem->current_regions);
    hostmem->current_regions = hostmem->new_regions;
    hostmem->num_current_regions = hostmem->num_new_regions;
    qemu_mutex_unlock(&hostmem->current_regions_lock);

    /* Reset new regions list */
    hostmem->new_regions = NULL;
    hostmem->num_new_regions = 0;
}

/**
 * Add a MemoryRegionSection to the new regions list
 */
static void hostmem_append_new_region(HostMem *hostmem,
                                      MemoryRegionSection *section)
{
    void *ram_ptr = memory_region_get_ram_ptr(section->mr);
    size_t num = hostmem->num_new_regions;
    size_t new_size = (num + 1) * sizeof(hostmem->new_regions[0]);

    hostmem->new_regions = g_realloc(hostmem->new_regions, new_size);
    hostmem->new_regions[num] = (HostMemRegion){
        .host_addr = ram_ptr + section->offset_within_region,
        .guest_addr = section->offset_within_address_space,
        .size = section->size,
        .readonly = section->readonly,
    };
    hostmem->num_new_regions++;
}

static void hostmem_listener_append_region(MemoryListener *listener,
                                           MemoryRegionSection *section)
{
    HostMem *hostmem = container_of(listener, HostMem, listener);

    /* Ignore non-RAM regions, we may not be able to map them */
    if (!memory_region_is_ram(section->mr)) {
        return;
    }

    /* Ignore regions with dirty logging, we cannot mark them dirty */
    if (memory_region_is_logging(section->mr)) {
        return;
    }

    hostmem_append_new_region(hostmem, section);
}

/* We don't implement most MemoryListener callbacks, use these nop stubs */
static void hostmem_listener_dummy(MemoryListener *listener)
{
}

static void hostmem_listener_section_dummy(MemoryListener *listener,
                                           MemoryRegionSection *section)
{
}

static void hostmem_listener_eventfd_dummy(MemoryListener *listener,
                                           MemoryRegionSection *section,
                                           bool match_data, uint64_t data,
                                           EventNotifier *e)
{
}

static void hostmem_listener_coalesced_mmio_dummy(MemoryListener *listener,
                                                  MemoryRegionSection *section,
                                                  hwaddr addr, hwaddr len)
{
}

void hostmem_init(HostMem *hostmem)
{
    memset(hostmem, 0, sizeof(*hostmem));

    qemu_mutex_init(&hostmem->current_regions_lock);

    hostmem->listener = (MemoryListener){
        .begin = hostmem_listener_dummy,
        .commit = hostmem_listener_commit,
        .region_add = hostmem_listener_append_region,
        .region_del = hostmem_listener_section_dummy,
        .region_nop = hostmem_listener_append_region,
        .log_start = hostmem_listener_section_dummy,
        .log_stop = hostmem_listener_section_dummy,
        .log_sync = hostmem_listener_section_dummy,
        .log_global_start = hostmem_listener_dummy,
        .log_global_stop = hostmem_listener_dummy,
        .eventfd_add = hostmem_listener_eventfd_dummy,
        .eventfd_del = hostmem_listener_eventfd_dummy,
        .coalesced_mmio_add = hostmem_listener_coalesced_mmio_dummy,
        .coalesced_mmio_del = hostmem_listener_coalesced_mmio_dummy,
        .priority = 10,
    };

    memory_listener_register(&hostmem->listener, &address_space_memory);
    if (hostmem->num_new_regions > 0) {
        hostmem_listener_commit(&hostmem->listener);
    }
}

void hostmem_finalize(HostMem *hostmem)
{
    memory_listener_unregister(&hostmem->listener);
    g_free(hostmem->new_regions);
    g_free(hostmem->current_regions);
    qemu_mutex_destroy(&hostmem->current_regions_lock);
}