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 <address@hidden>
---
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;