Add ref/unref calls at the following places: - places where memory regions are stashed by a listener and used outside the BQL (including in Xen or KVM). - memory_region_find callsites - creation of aliases and containers (only the aliased/contained region gets a reference to avoid loops) - around calls to del_subregion/add_subregion, where the region could disappear after the first call Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
184 lines
5.6 KiB
C
184 lines
5.6 KiB
C
/*
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* Thread-safe guest to host memory mapping
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*
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* Copyright 2012 Red Hat, Inc. and/or its affiliates
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*
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* Authors:
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* Stefan Hajnoczi <stefanha@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*
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*/
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#include "exec/address-spaces.h"
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#include "hw/virtio/dataplane/hostmem.h"
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static int hostmem_lookup_cmp(const void *phys_, const void *region_)
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{
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hwaddr phys = *(const hwaddr *)phys_;
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const HostMemRegion *region = region_;
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if (phys < region->guest_addr) {
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return -1;
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} else if (phys >= region->guest_addr + region->size) {
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return 1;
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} else {
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return 0;
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}
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}
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/**
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* Map guest physical address to host pointer
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*/
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void *hostmem_lookup(HostMem *hostmem, hwaddr phys, hwaddr len, bool is_write)
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{
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HostMemRegion *region;
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void *host_addr = NULL;
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hwaddr offset_within_region;
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qemu_mutex_lock(&hostmem->current_regions_lock);
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region = bsearch(&phys, hostmem->current_regions,
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hostmem->num_current_regions,
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sizeof(hostmem->current_regions[0]),
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hostmem_lookup_cmp);
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if (!region) {
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goto out;
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}
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if (is_write && region->readonly) {
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goto out;
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}
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offset_within_region = phys - region->guest_addr;
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if (len <= region->size - offset_within_region) {
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host_addr = region->host_addr + offset_within_region;
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}
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out:
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qemu_mutex_unlock(&hostmem->current_regions_lock);
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return host_addr;
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}
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/**
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* Install new regions list
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*/
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static void hostmem_listener_commit(MemoryListener *listener)
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{
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HostMem *hostmem = container_of(listener, HostMem, listener);
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int i;
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qemu_mutex_lock(&hostmem->current_regions_lock);
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for (i = 0; i < hostmem->num_current_regions; i++) {
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memory_region_unref(hostmem->current_regions[i].mr);
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}
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g_free(hostmem->current_regions);
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hostmem->current_regions = hostmem->new_regions;
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hostmem->num_current_regions = hostmem->num_new_regions;
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qemu_mutex_unlock(&hostmem->current_regions_lock);
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/* Reset new regions list */
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hostmem->new_regions = NULL;
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hostmem->num_new_regions = 0;
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}
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/**
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* Add a MemoryRegionSection to the new regions list
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*/
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static void hostmem_append_new_region(HostMem *hostmem,
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MemoryRegionSection *section)
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{
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void *ram_ptr = memory_region_get_ram_ptr(section->mr);
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size_t num = hostmem->num_new_regions;
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size_t new_size = (num + 1) * sizeof(hostmem->new_regions[0]);
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hostmem->new_regions = g_realloc(hostmem->new_regions, new_size);
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hostmem->new_regions[num] = (HostMemRegion){
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.host_addr = ram_ptr + section->offset_within_region,
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.guest_addr = section->offset_within_address_space,
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.size = int128_get64(section->size),
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.readonly = section->readonly,
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.mr = section->mr,
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};
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hostmem->num_new_regions++;
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memory_region_ref(section->mr);
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}
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static void hostmem_listener_append_region(MemoryListener *listener,
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MemoryRegionSection *section)
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{
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HostMem *hostmem = container_of(listener, HostMem, listener);
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/* Ignore non-RAM regions, we may not be able to map them */
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if (!memory_region_is_ram(section->mr)) {
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return;
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}
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/* Ignore regions with dirty logging, we cannot mark them dirty */
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if (memory_region_is_logging(section->mr)) {
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return;
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}
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hostmem_append_new_region(hostmem, section);
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}
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/* We don't implement most MemoryListener callbacks, use these nop stubs */
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static void hostmem_listener_dummy(MemoryListener *listener)
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{
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}
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static void hostmem_listener_section_dummy(MemoryListener *listener,
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MemoryRegionSection *section)
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{
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}
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static void hostmem_listener_eventfd_dummy(MemoryListener *listener,
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MemoryRegionSection *section,
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bool match_data, uint64_t data,
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EventNotifier *e)
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{
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}
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static void hostmem_listener_coalesced_mmio_dummy(MemoryListener *listener,
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MemoryRegionSection *section,
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hwaddr addr, hwaddr len)
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{
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}
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void hostmem_init(HostMem *hostmem)
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{
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memset(hostmem, 0, sizeof(*hostmem));
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qemu_mutex_init(&hostmem->current_regions_lock);
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hostmem->listener = (MemoryListener){
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.begin = hostmem_listener_dummy,
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.commit = hostmem_listener_commit,
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.region_add = hostmem_listener_append_region,
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.region_del = hostmem_listener_section_dummy,
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.region_nop = hostmem_listener_append_region,
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.log_start = hostmem_listener_section_dummy,
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.log_stop = hostmem_listener_section_dummy,
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.log_sync = hostmem_listener_section_dummy,
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.log_global_start = hostmem_listener_dummy,
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.log_global_stop = hostmem_listener_dummy,
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.eventfd_add = hostmem_listener_eventfd_dummy,
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.eventfd_del = hostmem_listener_eventfd_dummy,
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.coalesced_mmio_add = hostmem_listener_coalesced_mmio_dummy,
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.coalesced_mmio_del = hostmem_listener_coalesced_mmio_dummy,
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.priority = 10,
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};
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memory_listener_register(&hostmem->listener, &address_space_memory);
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if (hostmem->num_new_regions > 0) {
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hostmem_listener_commit(&hostmem->listener);
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}
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}
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void hostmem_finalize(HostMem *hostmem)
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{
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memory_listener_unregister(&hostmem->listener);
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g_free(hostmem->new_regions);
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g_free(hostmem->current_regions);
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qemu_mutex_destroy(&hostmem->current_regions_lock);
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}
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