Commit b2e0a138 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin

migration: stable ram block ordering

This makes ram block ordering under migration stable, ordered by offset.
This is especially useful for migration to exec, for debugging.
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Tested-by: default avatarJason Wang <jasowang@redhat.com>
parent c924f36a
......@@ -23,6 +23,7 @@
*/
#include <stdint.h>
#include <stdarg.h>
#include <stdlib.h>
#ifndef _WIN32
#include <sys/types.h>
#include <sys/mman.h>
......@@ -212,6 +213,39 @@ uint64_t ram_bytes_total(void)
return total;
}
static int block_compar(const void *a, const void *b)
{
RAMBlock * const *ablock = a;
RAMBlock * const *bblock = b;
if ((*ablock)->offset < (*bblock)->offset) {
return -1;
} else if ((*ablock)->offset > (*bblock)->offset) {
return 1;
}
return 0;
}
static void sort_ram_list(void)
{
RAMBlock *block, *nblock, **blocks;
int n;
n = 0;
QLIST_FOREACH(block, &ram_list.blocks, next) {
++n;
}
blocks = qemu_malloc(n * sizeof *blocks);
n = 0;
QLIST_FOREACH_SAFE(block, &ram_list.blocks, next, nblock) {
blocks[n++] = block;
QLIST_REMOVE(block, next);
}
qsort(blocks, n, sizeof *blocks, block_compar);
while (--n >= 0) {
QLIST_INSERT_HEAD(&ram_list.blocks, blocks[n], next);
}
qemu_free(blocks);
}
int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
{
ram_addr_t addr;
......@@ -234,6 +268,7 @@ int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
bytes_transferred = 0;
last_block = NULL;
last_offset = 0;
sort_ram_list();
/* Make sure all dirty bits are set */
QLIST_FOREACH(block, &ram_list.blocks, next) {
......
......@@ -46,6 +46,9 @@ ram_addr_t qemu_ram_alloc(DeviceState *dev, const char *name, ram_addr_t size);
void qemu_ram_free(ram_addr_t addr);
/* This should only be used for ram local to a device. */
void *qemu_get_ram_ptr(ram_addr_t addr);
/* Same but slower, to use for migration, where the order of
* RAMBlocks must not change. */
void *qemu_safe_ram_ptr(ram_addr_t addr);
/* This should not be used by devices. */
int qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr);
ram_addr_t qemu_ram_addr_from_host_nofail(void *ptr);
......
......@@ -2030,10 +2030,10 @@ void cpu_physical_memory_reset_dirty(ram_addr_t start, ram_addr_t end,
/* we modify the TLB cache so that the dirty bit will be set again
when accessing the range */
start1 = (unsigned long)qemu_get_ram_ptr(start);
start1 = (unsigned long)qemu_safe_ram_ptr(start);
/* Chek that we don't span multiple blocks - this breaks the
address comparisons below. */
if ((unsigned long)qemu_get_ram_ptr(end - 1) - start1
if ((unsigned long)qemu_safe_ram_ptr(end - 1) - start1
!= (end - 1) - start) {
abort();
}
......@@ -2858,6 +2858,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(DeviceState *dev, const char *name,
new_block->length = size;
QLIST_INSERT_HEAD(&ram_list.blocks, new_block, next);
fprintf(stderr, "alloc ram %s len 0x%x\n", new_block->idstr, (int)new_block->length);
ram_list.phys_dirty = qemu_realloc(ram_list.phys_dirty,
last_ram_offset() >> TARGET_PAGE_BITS);
......@@ -2931,6 +2932,25 @@ void *qemu_get_ram_ptr(ram_addr_t addr)
return NULL;
}
/* Return a host pointer to ram allocated with qemu_ram_alloc.
* Same as qemu_get_ram_ptr but avoid reordering ramblocks.
*/
void *qemu_safe_ram_ptr(ram_addr_t addr)
{
RAMBlock *block;
QLIST_FOREACH(block, &ram_list.blocks, next) {
if (addr - block->offset < block->length) {
return block->host + (addr - block->offset);
}
}
fprintf(stderr, "Bad ram offset %" PRIx64 "\n", (uint64_t)addr);
abort();
return NULL;
}
int qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr)
{
RAMBlock *block;
......
......@@ -162,7 +162,7 @@ static int kvm_set_user_memory_region(KVMState *s, KVMSlot *slot)
mem.slot = slot->slot;
mem.guest_phys_addr = slot->start_addr;
mem.memory_size = slot->memory_size;
mem.userspace_addr = (unsigned long)qemu_get_ram_ptr(slot->phys_offset);
mem.userspace_addr = (unsigned long)qemu_safe_ram_ptr(slot->phys_offset);
mem.flags = slot->flags;
if (s->migration_log) {
mem.flags |= KVM_MEM_LOG_DIRTY_PAGES;
......
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