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 #include "qemu-common.h"
  11
  12 #include "qemu/compiler.h"
  13 #include "qemu/int128.h"
  14 #include "qemu/range.h"
  15 #include "exec/memory.h"
  16 #include "exec/cpu-common.h"
  17 #include "exec/ram_addr.h"
  18 #include "qapi/error.h"
  19 #include "qemu/error-report.h"
  20 #include "hw/remote/mpqemu-link.h"
  21 #include "hw/remote/proxy-memory-listener.h"
  22
  23 /*
  24  * TODO: get_fd_from_hostaddr(), proxy_mrs_can_merge() and
  25  * proxy_memory_listener_commit() defined below perform tasks similar to the
  26  * functions defined in vhost-user.c. These functions are good candidates
  27  * for refactoring.
  28  *
  29  */
  30
  31 static void proxy_memory_listener_reset(MemoryListener *listener)
  32 {
  33     ProxyMemoryListener *proxy_listener = container_of(listener,
  34                                                        ProxyMemoryListener,
  35                                                        listener);
  36     int mrs;
  37
  38     for (mrs = 0; mrs < proxy_listener->n_mr_sections; mrs++) {
  39         memory_region_unref(proxy_listener->mr_sections[mrs].mr);
  40     }
  41
  42     g_free(proxy_listener->mr_sections);
  43     proxy_listener->mr_sections = NULL;
  44     proxy_listener->n_mr_sections = 0;
  45 }
  46
  47 static int get_fd_from_hostaddr(uint64_t host, ram_addr_t *offset)
  48 {
  49     MemoryRegion *mr;
  50     ram_addr_t off;
  51
  52     /**
  53      * Assumes that the host address is a valid address as it's
  54      * coming from the MemoryListener system. In the case host
  55      * address is not valid, the following call would return
  56      * the default subregion of "system_memory" region, and
  57      * not NULL. So it's not possible to check for NULL here.
  58      */
  59     mr = memory_region_from_host((void *)(uintptr_t)host, &off);
  60
  61     if (offset) {
  62         *offset = off;
  63     }
  64
  65     return memory_region_get_fd(mr);
  66 }
  67
  68 static bool proxy_mrs_can_merge(uint64_t host, uint64_t prev_host, size_t size)
  69 {
  70     if (((prev_host + size) != host)) {
  71         return false;
  72     }
  73
  74     if (get_fd_from_hostaddr(host, NULL) !=
  75             get_fd_from_hostaddr(prev_host, NULL)) {
  76         return false;
  77     }
  78
  79     return true;
  80 }
  81
  82 static bool try_merge(ProxyMemoryListener *proxy_listener,
  83                       MemoryRegionSection *section)
  84 {
  85     uint64_t mrs_size, mrs_gpa, mrs_page;
  86     MemoryRegionSection *prev_sec;
  87     bool merged = false;
  88     uintptr_t mrs_host;
  89     RAMBlock *mrs_rb;
  90
  91     if (!proxy_listener->n_mr_sections) {
  92         return false;
  93     }
  94
  95     mrs_rb = section->mr->ram_block;
  96     mrs_page = (uint64_t)qemu_ram_pagesize(mrs_rb);
  97     mrs_size = int128_get64(section->size);
  98     mrs_gpa = section->offset_within_address_space;
  99     mrs_host = (uintptr_t)memory_region_get_ram_ptr(section->mr) +
 100                section->offset_within_region;
 101
 102     if (get_fd_from_hostaddr(mrs_host, NULL) < 0) {
 103         return true;
 104     }
 105
 106     mrs_host = mrs_host & ~(mrs_page - 1);
 107     mrs_gpa = mrs_gpa & ~(mrs_page - 1);
 108     mrs_size = ROUND_UP(mrs_size, mrs_page);
 109
 110     prev_sec = proxy_listener->mr_sections +
 111                (proxy_listener->n_mr_sections - 1);
 112     uint64_t prev_gpa_start = prev_sec->offset_within_address_space;
 113     uint64_t prev_size = int128_get64(prev_sec->size);
 114     uint64_t prev_gpa_end   = range_get_last(prev_gpa_start, prev_size);
 115     uint64_t prev_host_start =
 116         (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr) +
 117         prev_sec->offset_within_region;
 118     uint64_t prev_host_end = range_get_last(prev_host_start, prev_size);
 119
 120     if (mrs_gpa <= (prev_gpa_end + 1)) {
 121         g_assert(mrs_gpa > prev_gpa_start);
 122
 123         if ((section->mr == prev_sec->mr) &&
 124             proxy_mrs_can_merge(mrs_host, prev_host_start,
 125                                 (mrs_gpa - prev_gpa_start))) {
 126             uint64_t max_end = MAX(prev_host_end, mrs_host + mrs_size);
 127             merged = true;
 128             prev_sec->offset_within_address_space =
 129                 MIN(prev_gpa_start, mrs_gpa);
 130             prev_sec->offset_within_region =
 131                 MIN(prev_host_start, mrs_host) -
 132                 (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr);
 133             prev_sec->size = int128_make64(max_end - MIN(prev_host_start,
 134                                                          mrs_host));
 135         }
 136     }
 137
 138     return merged;
 139 }
 140
 141 static void proxy_memory_listener_region_addnop(MemoryListener *listener,
 142                                                 MemoryRegionSection *section)
 143 {
 144     ProxyMemoryListener *proxy_listener = container_of(listener,
 145                                                        ProxyMemoryListener,
 146                                                        listener);
 147
 148     if (!memory_region_is_ram(section->mr) ||
 149             memory_region_is_rom(section->mr)) {
 150         return;
 151     }
 152
 153     if (try_merge(proxy_listener, section)) {
 154         return;
 155     }
 156
 157     ++proxy_listener->n_mr_sections;
 158     proxy_listener->mr_sections = g_renew(MemoryRegionSection,
 159                                           proxy_listener->mr_sections,
 160                                           proxy_listener->n_mr_sections);
 161     proxy_listener->mr_sections[proxy_listener->n_mr_sections - 1] = *section;
 162     proxy_listener->mr_sections[proxy_listener->n_mr_sections - 1].fv = NULL;
 163     memory_region_ref(section->mr);
 164 }
 165
 166 static void proxy_memory_listener_commit(MemoryListener *listener)
 167 {
 168     ProxyMemoryListener *proxy_listener = container_of(listener,
 169                                                        ProxyMemoryListener,
 170                                                        listener);
 171     MPQemuMsg msg;
 172     MemoryRegionSection *section;
 173     ram_addr_t offset;
 174     uintptr_t host_addr;
 175     int region;
 176     Error *local_err = NULL;
 177
 178     memset(&msg, 0, sizeof(MPQemuMsg));
 179
 180     msg.cmd = MPQEMU_CMD_SYNC_SYSMEM;
 181     msg.num_fds = proxy_listener->n_mr_sections;
 182     msg.size = sizeof(SyncSysmemMsg);
 183     if (msg.num_fds > REMOTE_MAX_FDS) {
 184         error_report("Number of fds is more than %d", REMOTE_MAX_FDS);
 185         return;
 186     }
 187
 188     for (region = 0; region < proxy_listener->n_mr_sections; region++) {
 189         section = &proxy_listener->mr_sections[region];
 190         msg.data.sync_sysmem.gpas[region] =
 191             section->offset_within_address_space;
 192         msg.data.sync_sysmem.sizes[region] = int128_get64(section->size);
 193         host_addr = (uintptr_t)memory_region_get_ram_ptr(section->mr) +
 194                     section->offset_within_region;
 195         msg.fds[region] = get_fd_from_hostaddr(host_addr, &offset);
 196         msg.data.sync_sysmem.offsets[region] = offset;
 197     }
 198     if (!mpqemu_msg_send(&msg, proxy_listener->ioc, &local_err)) {
 199         error_report_err(local_err);
 200     }
 201 }
 202
 203 void proxy_memory_listener_deconfigure(ProxyMemoryListener *proxy_listener)
 204 {
 205     memory_listener_unregister(&proxy_listener->listener);
 206
 207     proxy_memory_listener_reset(&proxy_listener->listener);
 208 }
 209
 210 void proxy_memory_listener_configure(ProxyMemoryListener *proxy_listener,
 211                                      QIOChannel *ioc)
 212 {
 213     proxy_listener->n_mr_sections = 0;
 214     proxy_listener->mr_sections = NULL;
 215
 216     proxy_listener->ioc = ioc;
 217
 218     proxy_listener->listener.begin = proxy_memory_listener_reset;
 219     proxy_listener->listener.commit = proxy_memory_listener_commit;
 220     proxy_listener->listener.region_add = proxy_memory_listener_region_addnop;
 221     proxy_listener->listener.region_nop = proxy_memory_listener_region_addnop;
 222     proxy_listener->listener.priority = 10;
 223     proxy_listener->listener.name = "proxy";
 224
 225     memory_listener_register(&proxy_listener->listener,
 226                              &address_space_memory);
 227 }