hw/remote/proxy-memory-listener.c

   1 /*
   2  * Copyright © 2018, 2021 Oracle and/or its affiliates.
   3  *
   4  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   5  * See the COPYING file in the top-level directory.
   6  *
   7  */
   8
   9 #include "qemu/osdep.h"
  10
  11 #include "qemu/int128.h"
  12 #include "qemu/range.h"
  13 #include "exec/memory.h"
  14 #include "exec/cpu-common.h"
  15 #include "exec/ram_addr.h"
  16 #include "qapi/error.h"
  17 #include "qemu/error-report.h"
  18 #include "hw/remote/mpqemu-link.h"
  19 #include "hw/remote/proxy-memory-listener.h"
  20
  21 /*
  22  * TODO: get_fd_from_hostaddr(), proxy_mrs_can_merge() and
  23  * proxy_memory_listener_commit() defined below perform tasks similar to the
  24  * functions defined in vhost-user.c. These functions are good candidates
  25  * for refactoring.
  26  *
  27  */
  28
  29 static void proxy_memory_listener_reset(MemoryListener *listener)
  30 {
  31     ProxyMemoryListener *proxy_listener = container_of(listener,
  32                                                        ProxyMemoryListener,
  33                                                        listener);
  34     int mrs;
  35
  36     for (mrs = 0; mrs < proxy_listener->n_mr_sections; mrs++) {
  37         memory_region_unref(proxy_listener->mr_sections[mrs].mr);
  38     }
  39
  40     g_free(proxy_listener->mr_sections);
  41     proxy_listener->mr_sections = NULL;
  42     proxy_listener->n_mr_sections = 0;
  43 }
  44
  45 static int get_fd_from_hostaddr(uint64_t host, ram_addr_t *offset)
  46 {
  47     MemoryRegion *mr;
  48     ram_addr_t off;
  49
  50     /**
  51      * Assumes that the host address is a valid address as it's
  52      * coming from the MemoryListener system. In the case host
  53      * address is not valid, the following call would return
  54      * the default subregion of "system_memory" region, and
  55      * not NULL. So it's not possible to check for NULL here.
  56      */
  57     mr = memory_region_from_host((void *)(uintptr_t)host, &off);
  58
  59     if (offset) {
  60         *offset = off;
  61     }
  62
  63     return memory_region_get_fd(mr);
  64 }
  65
  66 static bool proxy_mrs_can_merge(uint64_t host, uint64_t prev_host, size_t size)
  67 {
  68     if (((prev_host + size) != host)) {
  69         return false;
  70     }
  71
  72     if (get_fd_from_hostaddr(host, NULL) !=
  73             get_fd_from_hostaddr(prev_host, NULL)) {
  74         return false;
  75     }
  76
  77     return true;
  78 }
  79
  80 static bool try_merge(ProxyMemoryListener *proxy_listener,
  81                       MemoryRegionSection *section)
  82 {
  83     uint64_t mrs_size, mrs_gpa, mrs_page;
  84     MemoryRegionSection *prev_sec;
  85     bool merged = false;
  86     uintptr_t mrs_host;
  87     RAMBlock *mrs_rb;
  88
  89     if (!proxy_listener->n_mr_sections) {
  90         return false;
  91     }
  92
  93     mrs_rb = section->mr->ram_block;
  94     mrs_page = (uint64_t)qemu_ram_pagesize(mrs_rb);
  95     mrs_size = int128_get64(section->size);
  96     mrs_gpa = section->offset_within_address_space;
  97     mrs_host = (uintptr_t)memory_region_get_ram_ptr(section->mr) +
  98                section->offset_within_region;
  99
 100     if (get_fd_from_hostaddr(mrs_host, NULL) < 0) {
 101         return true;
 102     }
 103
 104     mrs_host = mrs_host & ~(mrs_page - 1);
 105     mrs_gpa = mrs_gpa & ~(mrs_page - 1);
 106     mrs_size = ROUND_UP(mrs_size, mrs_page);
 107
 108     prev_sec = proxy_listener->mr_sections +
 109                (proxy_listener->n_mr_sections - 1);
 110     uint64_t prev_gpa_start = prev_sec->offset_within_address_space;
 111     uint64_t prev_size = int128_get64(prev_sec->size);
 112     uint64_t prev_gpa_end   = range_get_last(prev_gpa_start, prev_size);
 113     uint64_t prev_host_start =
 114         (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr) +
 115         prev_sec->offset_within_region;
 116     uint64_t prev_host_end = range_get_last(prev_host_start, prev_size);
 117
 118     if (mrs_gpa <= (prev_gpa_end + 1)) {
 119         g_assert(mrs_gpa > prev_gpa_start);
 120
 121         if ((section->mr == prev_sec->mr) &&
 122             proxy_mrs_can_merge(mrs_host, prev_host_start,
 123                                 (mrs_gpa - prev_gpa_start))) {
 124             uint64_t max_end = MAX(prev_host_end, mrs_host + mrs_size);
 125             merged = true;
 126             prev_sec->offset_within_address_space =
 127                 MIN(prev_gpa_start, mrs_gpa);
 128             prev_sec->offset_within_region =
 129                 MIN(prev_host_start, mrs_host) -
 130                 (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr);
 131             prev_sec->size = int128_make64(max_end - MIN(prev_host_start,
 132                                                          mrs_host));
 133         }
 134     }
 135
 136     return merged;
 137 }
 138
 139 static void proxy_memory_listener_region_addnop(MemoryListener *listener,
 140                                                 MemoryRegionSection *section)
 141 {
 142     ProxyMemoryListener *proxy_listener = container_of(listener,
 143                                                        ProxyMemoryListener,
 144                                                        listener);
 145
 146     if (!memory_region_is_ram(section->mr) ||
 147             memory_region_is_rom(section->mr)) {
 148         return;
 149     }
 150
 151     if (try_merge(proxy_listener, section)) {
 152         return;
 153     }
 154
 155     ++proxy_listener->n_mr_sections;
 156     proxy_listener->mr_sections = g_renew(MemoryRegionSection,
 157                                           proxy_listener->mr_sections,
 158                                           proxy_listener->n_mr_sections);
 159     proxy_listener->mr_sections[proxy_listener->n_mr_sections - 1] = *section;
 160     proxy_listener->mr_sections[proxy_listener->n_mr_sections - 1].fv = NULL;
 161     memory_region_ref(section->mr);
 162 }
 163
 164 static void proxy_memory_listener_commit(MemoryListener *listener)
 165 {
 166     ProxyMemoryListener *proxy_listener = container_of(listener,
 167                                                        ProxyMemoryListener,
 168                                                        listener);
 169     MPQemuMsg msg;
 170     MemoryRegionSection *section;
 171     ram_addr_t offset;
 172     uintptr_t host_addr;
 173     int region;
 174     Error *local_err = NULL;
 175
 176     memset(&msg, 0, sizeof(MPQemuMsg));
 177
 178     msg.cmd = MPQEMU_CMD_SYNC_SYSMEM;
 179     msg.num_fds = proxy_listener->n_mr_sections;
 180     msg.size = sizeof(SyncSysmemMsg);
 181     if (msg.num_fds > REMOTE_MAX_FDS) {
 182         error_report("Number of fds is more than %d", REMOTE_MAX_FDS);
 183         return;
 184     }
 185
 186     for (region = 0; region < proxy_listener->n_mr_sections; region++) {
 187         section = &proxy_listener->mr_sections[region];
 188         msg.data.sync_sysmem.gpas[region] =
 189             section->offset_within_address_space;
 190         msg.data.sync_sysmem.sizes[region] = int128_get64(section->size);
 191         host_addr = (uintptr_t)memory_region_get_ram_ptr(section->mr) +
 192                     section->offset_within_region;
 193         msg.fds[region] = get_fd_from_hostaddr(host_addr, &offset);
 194         msg.data.sync_sysmem.offsets[region] = offset;
 195     }
 196     if (!mpqemu_msg_send(&msg, proxy_listener->ioc, &local_err)) {
 197         error_report_err(local_err);
 198     }
 199 }
 200
 201 void proxy_memory_listener_deconfigure(ProxyMemoryListener *proxy_listener)
 202 {
 203     memory_listener_unregister(&proxy_listener->listener);
 204
 205     proxy_memory_listener_reset(&proxy_listener->listener);
 206 }
 207
 208 void proxy_memory_listener_configure(ProxyMemoryListener *proxy_listener,
 209                                      QIOChannel *ioc)
 210 {
 211     proxy_listener->n_mr_sections = 0;
 212     proxy_listener->mr_sections = NULL;
 213
 214     proxy_listener->ioc = ioc;
 215
 216     proxy_listener->listener.begin = proxy_memory_listener_reset;
 217     proxy_listener->listener.commit = proxy_memory_listener_commit;
 218     proxy_listener->listener.region_add = proxy_memory_listener_region_addnop;
 219     proxy_listener->listener.region_nop = proxy_memory_listener_region_addnop;
 220     proxy_listener->listener.priority = MEMORY_LISTENER_PRIORITY_DEV_BACKEND;
 221     proxy_listener->listener.name = "proxy";
 222
 223     memory_listener_register(&proxy_listener->listener,
 224                              &address_space_memory);
 225 }