While the machine is paused, in guest_phys_blocks_append() we register a one-shot MemoryListener, solely for the initial collection of the valid guest-physical memory ranges that happens at client registration time.
For each range that is reported to guest_phys_blocks_set_memory(), we attempt to merge the range with adjacent (preceding, subsequent, or both) ranges. We use two hash tables for this purpose, both indexing the same ranges, just by different keys (guest-phys-start vs. guest-phys-end). Ranges can only be joined if they are contiguous in both guest-physical address space, and contiguous in host virtual address space. The "maximal" ranges that remain in the end constitute the guest-physical memory map that the dump will be based on. Related RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=981582 Signed-off-by: Laszlo Ersek <ler...@redhat.com> --- include/sysemu/memory_mapping.h | 1 + dump.c | 2 +- memory_mapping.c | 135 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 137 insertions(+), 1 deletions(-) diff --git a/include/sysemu/memory_mapping.h b/include/sysemu/memory_mapping.h index 53c2cd5..6723dc5 100644 --- a/include/sysemu/memory_mapping.h +++ b/include/sysemu/memory_mapping.h @@ -66,6 +66,7 @@ void memory_mapping_list_init(MemoryMappingList *list); void guest_phys_blocks_free(GuestPhysBlockList *list); void guest_phys_blocks_init(GuestPhysBlockList *list); +void guest_phys_blocks_append(GuestPhysBlockList *list); void qemu_get_guest_memory_mapping(MemoryMappingList *list, Error **errp); diff --git a/dump.c b/dump.c index 716fb1d..3fa33fc 100644 --- a/dump.c +++ b/dump.c @@ -746,7 +746,7 @@ static int dump_init(DumpState *s, int fd, bool paging, bool has_filter, s->length = length; guest_phys_blocks_init(&s->guest_phys_blocks); - /* FILL LIST */ + guest_phys_blocks_append(&s->guest_phys_blocks); s->start = get_start_block(s); if (s->start == -1) { diff --git a/memory_mapping.c b/memory_mapping.c index c70505b..efaabf8 100644 --- a/memory_mapping.c +++ b/memory_mapping.c @@ -11,9 +11,13 @@ * */ +#include <glib.h> + #include "cpu.h" #include "exec/cpu-all.h" #include "sysemu/memory_mapping.h" +#include "exec/memory.h" +#include "exec/address-spaces.h" static void memory_mapping_list_add_mapping_sorted(MemoryMappingList *list, MemoryMapping *mapping) @@ -182,6 +186,137 @@ void guest_phys_blocks_init(GuestPhysBlockList *list) QTAILQ_INIT(&list->head); } +typedef struct GuestPhysListener { + GHashTable *by_target_start; + GHashTable *by_target_end; + MemoryListener listener; +} GuestPhysListener; + +static void guest_phys_blocks_region_add(MemoryListener *listener, + MemoryRegionSection *section) +{ + GuestPhysListener *g; + uint64_t section_size; + hwaddr target_start, target_end; + uint8_t *host_addr; + GuestPhysBlock *predecessor, *successor, *block; + bool found; + + /* we only care about RAM */ + if (!memory_region_is_ram(section->mr)) { + return; + } + + g = container_of(listener, GuestPhysListener, listener); + section_size = int128_get64(section->size); + target_start = section->offset_within_address_space; + target_end = target_start + section_size; + host_addr = memory_region_get_ram_ptr(section->mr) + + section->offset_within_region; + + /* find continuity in guest physical address space */ + predecessor = g_hash_table_lookup(g->by_target_end, &target_start); + successor = g_hash_table_lookup(g->by_target_start, &target_end); + + /* we require continuity in host memory too */ + if (predecessor != NULL) { + hwaddr predecessor_size = predecessor->target_end - + predecessor->target_start; + if (predecessor->host_addr + predecessor_size != host_addr) { + predecessor = NULL; + } + } + if (successor != NULL + && host_addr + section_size != successor->host_addr) { + successor = NULL; + } + + if (predecessor == NULL) { + if (successor == NULL) { + /* Isolated mapping, allocate it and add it to both tables. */ + block = g_malloc0(sizeof *block); + + block->target_end = target_end; + g_hash_table_insert(g->by_target_end, &block->target_end, block); + } else { + /* Mapping has successor only. Merge current into successor by + * modifying successor's start. Successor's end doesn't change. + */ + block = successor; + found = g_hash_table_steal(g->by_target_start, + &block->target_start); + g_assert(found); + } + block->target_start = target_start; + block->host_addr = host_addr; + g_hash_table_insert(g->by_target_start, &block->target_start, block); + return; + } + + if (successor != NULL) { + /* Mapping has both predecessor and successor. Delete the successor + * and expand the predecessor to cover all three. + */ + target_end = successor->target_end; + + found = g_hash_table_steal(g->by_target_end, &successor->target_end); + g_assert(found); + found = g_hash_table_steal(g->by_target_start, + &successor->target_start); + g_assert(found); + + g_free(successor); + } + /* otherwise, mapping has predecessor only */ + + /* Expand predecessor until @target_end. Predecessor's start doesn't + * change. + */ + block = predecessor; + found = g_hash_table_steal(g->by_target_end, &block->target_end); + g_assert(found); + + block->target_end = target_end; + g_hash_table_insert(g->by_target_end, &block->target_end, block); +} + +static void guest_phys_block_link(gpointer key, gpointer value, + gpointer user_data) +{ + GuestPhysBlock *block = value; + GuestPhysBlockList *list = user_data; + + QTAILQ_INSERT_TAIL(&list->head, block, next); + ++list->num; +} + +void guest_phys_blocks_append(GuestPhysBlockList *list) +{ + GHashFunc hash_func; + GEqualFunc equal_func; + GuestPhysListener g = { 0 }; + + if (sizeof(hwaddr) == sizeof(uint64_t)) { + hash_func = &g_int64_hash; + equal_func = &g_int64_equal; + } else { + hash_func = &g_int_hash; + equal_func = &g_int_equal; + } + + g.by_target_start = g_hash_table_new(hash_func, equal_func); + g.by_target_end = g_hash_table_new(hash_func, equal_func); + + g.listener.region_add = &guest_phys_blocks_region_add; + memory_listener_register(&g.listener, &address_space_memory); + memory_listener_unregister(&g.listener); + + g_hash_table_foreach(g.by_target_start, &guest_phys_block_link, list); + + g_hash_table_destroy(g.by_target_end); + g_hash_table_destroy(g.by_target_start); +} + static CPUState *find_paging_enabled_cpu(CPUState *start_cpu) { CPUState *cpu; -- 1.7.1