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077874e01f
qemu/include/exec/ram_addr.h
Peter Xu 077874e01f memory: Introduce memory listener hook log_clear() 
Introduce a new memory region listener hook log_clear() to allow the
listeners to hook onto the points where the dirty bitmap is cleared by
the bitmap users.

Previously log_sync() contains two operations:

  - dirty bitmap collection, and,
  - dirty bitmap clear on remote site.

Let's take KVM as example - log_sync() for KVM will first copy the
kernel dirty bitmap to userspace, and at the same time we'll clear the
dirty bitmap there along with re-protecting all the guest pages again.

We add this new log_clear() interface only to split the old log_sync()
into two separated procedures:

  - use log_sync() to collect the collection only, and,
  - use log_clear() to clear the remote dirty bitmap.

With the new interface, the memory listener users will still be able
to decide how to implement the log synchronization procedure, e.g.,
they can still only provide log_sync() method only and put all the two
procedures within log_sync() (that's how the old KVM works before
KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is introduced).  However with this
new interface the memory listener users will start to have a chance to
postpone the log clear operation explicitly if the module supports.
That can really benefit users like KVM at least for host kernels that
support KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2.

There are three places that can clear dirty bits in any one of the
dirty bitmap in the ram_list.dirty_memory[3] array:

        cpu_physical_memory_snapshot_and_clear_dirty
        cpu_physical_memory_test_and_clear_dirty
        cpu_physical_memory_sync_dirty_bitmap

Currently we hook directly into each of the functions to notify about
the log_clear().

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20190603065056.25211-7-peterx@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2019-07-15 15:39:02 +02:00

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/*
* Declarations for cpu physical memory functions
*
* Copyright 2011 Red Hat, Inc. and/or its affiliates
*
* Authors:
* Avi Kivity <avi@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*
*/
/*
* This header is for use by exec.c and memory.c ONLY. Do not include it.
* The functions declared here will be removed soon.
*/
#ifndef RAM_ADDR_H
#define RAM_ADDR_H
#ifndef CONFIG_USER_ONLY
#include "hw/xen/xen.h"
#include "sysemu/tcg.h"
#include "exec/ramlist.h"
struct RAMBlock {
struct rcu_head rcu;
struct MemoryRegion *mr;
uint8_t *host;
uint8_t *colo_cache; /* For colo, VM's ram cache */
ram_addr_t offset;
ram_addr_t used_length;
ram_addr_t max_length;
void (*resized)(const char*, uint64_t length, void *host);
uint32_t flags;
/* Protected by iothread lock. */
char idstr[256];
/* RCU-enabled, writes protected by the ramlist lock */
QLIST_ENTRY(RAMBlock) next;
QLIST_HEAD(, RAMBlockNotifier) ramblock_notifiers;
int fd;
size_t page_size;
/* dirty bitmap used during migration */
unsigned long *bmap;
/* bitmap of pages that haven't been sent even once
* only maintained and used in postcopy at the moment
* where it's used to send the dirtymap at the start
* of the postcopy phase
*/
unsigned long *unsentmap;
/* bitmap of already received pages in postcopy */
unsigned long *receivedmap;
};
static inline bool offset_in_ramblock(RAMBlock *b, ram_addr_t offset)
{
return (b && b->host && offset < b->used_length) ? true : false;
}
static inline void *ramblock_ptr(RAMBlock *block, ram_addr_t offset)
{
assert(offset_in_ramblock(block, offset));
return (char *)block->host + offset;
}
static inline unsigned long int ramblock_recv_bitmap_offset(void *host_addr,
RAMBlock *rb)
{
uint64_t host_addr_offset =
(uint64_t)(uintptr_t)(host_addr - (void *)rb->host);
return host_addr_offset >> TARGET_PAGE_BITS;
}
bool ramblock_is_pmem(RAMBlock *rb);
long qemu_minrampagesize(void);
long qemu_maxrampagesize(void);
/**
* qemu_ram_alloc_from_file,
* qemu_ram_alloc_from_fd: Allocate a ram block from the specified backing
* file or device
*
* Parameters:
* @size: the size in bytes of the ram block
* @mr: the memory region where the ram block is
* @ram_flags: specify the properties of the ram block, which can be one
* or bit-or of following values
* - RAM_SHARED: mmap the backing file or device with MAP_SHARED
* - RAM_PMEM: the backend @mem_path or @fd is persistent memory
* Other bits are ignored.
* @mem_path or @fd: specify the backing file or device
* @errp: pointer to Error*, to store an error if it happens
*
* Return:
* On success, return a pointer to the ram block.
* On failure, return NULL.
*/
RAMBlock *qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
uint32_t ram_flags, const char *mem_path,
Error **errp);
RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
uint32_t ram_flags, int fd,
Error **errp);
RAMBlock *qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
MemoryRegion *mr, Error **errp);
RAMBlock *qemu_ram_alloc(ram_addr_t size, bool share, MemoryRegion *mr,
Error **errp);
RAMBlock *qemu_ram_alloc_resizeable(ram_addr_t size, ram_addr_t max_size,
void (*resized)(const char*,
uint64_t length,
void *host),
MemoryRegion *mr, Error **errp);
void qemu_ram_free(RAMBlock *block);
int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp);
#define DIRTY_CLIENTS_ALL ((1 << DIRTY_MEMORY_NUM) - 1)
#define DIRTY_CLIENTS_NOCODE (DIRTY_CLIENTS_ALL & ~(1 << DIRTY_MEMORY_CODE))
void tb_invalidate_phys_range(ram_addr_t start, ram_addr_t end);
static inline bool cpu_physical_memory_get_dirty(ram_addr_t start,
ram_addr_t length,
unsigned client)
{
DirtyMemoryBlocks *blocks;
unsigned long end, page;
unsigned long idx, offset, base;
bool dirty = false;
assert(client < DIRTY_MEMORY_NUM);
end = TARGET_PAGE_ALIGN(start + length) >> TARGET_PAGE_BITS;
page = start >> TARGET_PAGE_BITS;
rcu_read_lock();
blocks = atomic_rcu_read(&ram_list.dirty_memory[client]);
idx = page / DIRTY_MEMORY_BLOCK_SIZE;
offset = page % DIRTY_MEMORY_BLOCK_SIZE;
base = page - offset;
while (page < end) {
unsigned long next = MIN(end, base + DIRTY_MEMORY_BLOCK_SIZE);
unsigned long num = next - base;
unsigned long found = find_next_bit(blocks->blocks[idx], num, offset);
if (found < num) {
dirty = true;
break;
}
page = next;
idx++;
offset = 0;
base += DIRTY_MEMORY_BLOCK_SIZE;
}
rcu_read_unlock();
return dirty;
}
static inline bool cpu_physical_memory_all_dirty(ram_addr_t start,
ram_addr_t length,
unsigned client)
{
DirtyMemoryBlocks *blocks;
unsigned long end, page;
unsigned long idx, offset, base;
bool dirty = true;
assert(client < DIRTY_MEMORY_NUM);
end = TARGET_PAGE_ALIGN(start + length) >> TARGET_PAGE_BITS;
page = start >> TARGET_PAGE_BITS;
rcu_read_lock();
blocks = atomic_rcu_read(&ram_list.dirty_memory[client]);
idx = page / DIRTY_MEMORY_BLOCK_SIZE;
offset = page % DIRTY_MEMORY_BLOCK_SIZE;
base = page - offset;
while (page < end) {
unsigned long next = MIN(end, base + DIRTY_MEMORY_BLOCK_SIZE);
unsigned long num = next - base;
unsigned long found = find_next_zero_bit(blocks->blocks[idx], num, offset);
if (found < num) {
dirty = false;
break;
}
page = next;
idx++;
offset = 0;
base += DIRTY_MEMORY_BLOCK_SIZE;
}
rcu_read_unlock();
return dirty;
}
static inline bool cpu_physical_memory_get_dirty_flag(ram_addr_t addr,
unsigned client)
{
return cpu_physical_memory_get_dirty(addr, 1, client);
}
static inline bool cpu_physical_memory_is_clean(ram_addr_t addr)
{
bool vga = cpu_physical_memory_get_dirty_flag(addr, DIRTY_MEMORY_VGA);
bool code = cpu_physical_memory_get_dirty_flag(addr, DIRTY_MEMORY_CODE);
bool migration =
cpu_physical_memory_get_dirty_flag(addr, DIRTY_MEMORY_MIGRATION);
return !(vga && code && migration);
}
static inline uint8_t cpu_physical_memory_range_includes_clean(ram_addr_t start,
ram_addr_t length,
uint8_t mask)
{
uint8_t ret = 0;
if (mask & (1 << DIRTY_MEMORY_VGA) &&
!cpu_physical_memory_all_dirty(start, length, DIRTY_MEMORY_VGA)) {
ret |= (1 << DIRTY_MEMORY_VGA);
}
if (mask & (1 << DIRTY_MEMORY_CODE) &&
!cpu_physical_memory_all_dirty(start, length, DIRTY_MEMORY_CODE)) {
ret |= (1 << DIRTY_MEMORY_CODE);
}
if (mask & (1 << DIRTY_MEMORY_MIGRATION) &&
!cpu_physical_memory_all_dirty(start, length, DIRTY_MEMORY_MIGRATION)) {
ret |= (1 << DIRTY_MEMORY_MIGRATION);
}
return ret;
}
static inline void cpu_physical_memory_set_dirty_flag(ram_addr_t addr,
unsigned client)
{
unsigned long page, idx, offset;
DirtyMemoryBlocks *blocks;
assert(client < DIRTY_MEMORY_NUM);
page = addr >> TARGET_PAGE_BITS;
idx = page / DIRTY_MEMORY_BLOCK_SIZE;
offset = page % DIRTY_MEMORY_BLOCK_SIZE;
rcu_read_lock();
blocks = atomic_rcu_read(&ram_list.dirty_memory[client]);
set_bit_atomic(offset, blocks->blocks[idx]);
rcu_read_unlock();
}
static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start,
ram_addr_t length,
uint8_t mask)
{
DirtyMemoryBlocks *blocks[DIRTY_MEMORY_NUM];
unsigned long end, page;
unsigned long idx, offset, base;
int i;
if (!mask && !xen_enabled()) {
return;
}
end = TARGET_PAGE_ALIGN(start + length) >> TARGET_PAGE_BITS;
page = start >> TARGET_PAGE_BITS;
rcu_read_lock();
for (i = 0; i < DIRTY_MEMORY_NUM; i++) {
blocks[i] = atomic_rcu_read(&ram_list.dirty_memory[i]);
}
idx = page / DIRTY_MEMORY_BLOCK_SIZE;
offset = page % DIRTY_MEMORY_BLOCK_SIZE;
base = page - offset;
while (page < end) {
unsigned long next = MIN(end, base + DIRTY_MEMORY_BLOCK_SIZE);
if (likely(mask & (1 << DIRTY_MEMORY_MIGRATION))) {
bitmap_set_atomic(blocks[DIRTY_MEMORY_MIGRATION]->blocks[idx],
offset, next - page);
}
if (unlikely(mask & (1 << DIRTY_MEMORY_VGA))) {
bitmap_set_atomic(blocks[DIRTY_MEMORY_VGA]->blocks[idx],
offset, next - page);
}
if (unlikely(mask & (1 << DIRTY_MEMORY_CODE))) {
bitmap_set_atomic(blocks[DIRTY_MEMORY_CODE]->blocks[idx],
offset, next - page);
}
page = next;
idx++;
offset = 0;
base += DIRTY_MEMORY_BLOCK_SIZE;
}
rcu_read_unlock();
xen_hvm_modified_memory(start, length);
}
#if !defined(_WIN32)
static inline void cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap,
ram_addr_t start,
ram_addr_t pages)
{
unsigned long i, j;
unsigned long page_number, c;
hwaddr addr;
ram_addr_t ram_addr;
unsigned long len = (pages + HOST_LONG_BITS - 1) / HOST_LONG_BITS;
unsigned long hpratio = getpagesize() / TARGET_PAGE_SIZE;
unsigned long page = BIT_WORD(start >> TARGET_PAGE_BITS);
/* start address is aligned at the start of a word? */
if ((((page * BITS_PER_LONG) << TARGET_PAGE_BITS) == start) &&
(hpratio == 1)) {
unsigned long **blocks[DIRTY_MEMORY_NUM];
unsigned long idx;
unsigned long offset;
long k;
long nr = BITS_TO_LONGS(pages);
idx = (start >> TARGET_PAGE_BITS) / DIRTY_MEMORY_BLOCK_SIZE;
offset = BIT_WORD((start >> TARGET_PAGE_BITS) %
DIRTY_MEMORY_BLOCK_SIZE);
rcu_read_lock();
for (i = 0; i < DIRTY_MEMORY_NUM; i++) {
blocks[i] = atomic_rcu_read(&ram_list.dirty_memory[i])->blocks;
}
for (k = 0; k < nr; k++) {
if (bitmap[k]) {
unsigned long temp = leul_to_cpu(bitmap[k]);
atomic_or(&blocks[DIRTY_MEMORY_VGA][idx][offset], temp);
if (global_dirty_log) {
atomic_or(&blocks[DIRTY_MEMORY_MIGRATION][idx][offset],
temp);
}
if (tcg_enabled()) {
atomic_or(&blocks[DIRTY_MEMORY_CODE][idx][offset], temp);
}
}
if (++offset >= BITS_TO_LONGS(DIRTY_MEMORY_BLOCK_SIZE)) {
offset = 0;
idx++;
}
}
rcu_read_unlock();
xen_hvm_modified_memory(start, pages << TARGET_PAGE_BITS);
} else {
uint8_t clients = tcg_enabled() ? DIRTY_CLIENTS_ALL : DIRTY_CLIENTS_NOCODE;
if (!global_dirty_log) {
clients &= ~(1 << DIRTY_MEMORY_MIGRATION);
}
/*
* bitmap-traveling is faster than memory-traveling (for addr...)
* especially when most of the memory is not dirty.
*/
for (i = 0; i < len; i++) {
if (bitmap[i] != 0) {
c = leul_to_cpu(bitmap[i]);
do {
j = ctzl(c);
c &= ~(1ul << j);
page_number = (i * HOST_LONG_BITS + j) * hpratio;
addr = page_number * TARGET_PAGE_SIZE;
ram_addr = start + addr;
cpu_physical_memory_set_dirty_range(ram_addr,
TARGET_PAGE_SIZE * hpratio, clients);
} while (c != 0);
}
}
}
}
#endif /* not _WIN32 */
bool cpu_physical_memory_test_and_clear_dirty(ram_addr_t start,
ram_addr_t length,
unsigned client);
DirtyBitmapSnapshot *cpu_physical_memory_snapshot_and_clear_dirty
(MemoryRegion *mr, hwaddr offset, hwaddr length, unsigned client);
bool cpu_physical_memory_snapshot_get_dirty(DirtyBitmapSnapshot *snap,
ram_addr_t start,
ram_addr_t length);
static inline void cpu_physical_memory_clear_dirty_range(ram_addr_t start,
ram_addr_t length)
{
cpu_physical_memory_test_and_clear_dirty(start, length, DIRTY_MEMORY_MIGRATION);
cpu_physical_memory_test_and_clear_dirty(start, length, DIRTY_MEMORY_VGA);
cpu_physical_memory_test_and_clear_dirty(start, length, DIRTY_MEMORY_CODE);
}
/* Called with RCU critical section */
static inline
uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb,
ram_addr_t start,
ram_addr_t length,
uint64_t *real_dirty_pages)
{
ram_addr_t addr;
unsigned long word = BIT_WORD((start + rb->offset) >> TARGET_PAGE_BITS);
uint64_t num_dirty = 0;
unsigned long *dest = rb->bmap;
/* start address and length is aligned at the start of a word? */
if (((word * BITS_PER_LONG) << TARGET_PAGE_BITS) ==
(start + rb->offset) &&
!(length & ((BITS_PER_LONG << TARGET_PAGE_BITS) - 1))) {
int k;
int nr = BITS_TO_LONGS(length >> TARGET_PAGE_BITS);
unsigned long * const *src;
unsigned long idx = (word * BITS_PER_LONG) / DIRTY_MEMORY_BLOCK_SIZE;
unsigned long offset = BIT_WORD((word * BITS_PER_LONG) %
DIRTY_MEMORY_BLOCK_SIZE);
unsigned long page = BIT_WORD(start >> TARGET_PAGE_BITS);
src = atomic_rcu_read(
&ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION])->blocks;
for (k = page; k < page + nr; k++) {
if (src[idx][offset]) {
unsigned long bits = atomic_xchg(&src[idx][offset], 0);
unsigned long new_dirty;
*real_dirty_pages += ctpopl(bits);
new_dirty = ~dest[k];
dest[k] |= bits;
new_dirty &= bits;
num_dirty += ctpopl(new_dirty);
}
if (++offset >= BITS_TO_LONGS(DIRTY_MEMORY_BLOCK_SIZE)) {
offset = 0;
idx++;
}
}
/* TODO: split the huge bitmap into smaller chunks */
memory_region_clear_dirty_bitmap(rb->mr, start, length);
} else {
ram_addr_t offset = rb->offset;
for (addr = 0; addr < length; addr += TARGET_PAGE_SIZE) {
if (cpu_physical_memory_test_and_clear_dirty(
start + addr + offset,
TARGET_PAGE_SIZE,
DIRTY_MEMORY_MIGRATION)) {
*real_dirty_pages += 1;
long k = (start + addr) >> TARGET_PAGE_BITS;
if (!test_and_set_bit(k, dest)) {
num_dirty++;
}
}
}
}
return num_dirty;
}
#endif
#endif
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