qemu/include/exec/ram_addr.h
Peter Xu cedb70eafb migration: Use non-atomic ops for clear log bitmap
Since we already have bitmap_mutex to protect either the dirty bitmap or
the clear log bitmap, we don't need atomic operations to set/clear/test on
the clear log bitmap.  Switching all ops from atomic to non-atomic
versions, meanwhile touch up the comments to show which lock is in charge.

Introduced non-atomic version of bitmap_test_and_clear_atomic(), mostly the
same as the atomic version but simplified a few places, e.g. dropped the
"old_bits" variable, and also the explicit memory barriers.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2022-11-21 11:58:10 +01:00

523 lines
17 KiB
C

/*
* 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 "cpu.h"
#include "sysemu/xen.h"
#include "sysemu/tcg.h"
#include "exec/ramlist.h"
#include "exec/ramblock.h"
extern uint64_t total_dirty_pages;
/**
* clear_bmap_size: calculate clear bitmap size
*
* @pages: number of guest pages
* @shift: guest page number shift
*
* Returns: number of bits for the clear bitmap
*/
static inline long clear_bmap_size(uint64_t pages, uint8_t shift)
{
return DIV_ROUND_UP(pages, 1UL << shift);
}
/**
* clear_bmap_set: set clear bitmap for the page range. Must be with
* bitmap_mutex held.
*
* @rb: the ramblock to operate on
* @start: the start page number
* @size: number of pages to set in the bitmap
*
* Returns: None
*/
static inline void clear_bmap_set(RAMBlock *rb, uint64_t start,
uint64_t npages)
{
uint8_t shift = rb->clear_bmap_shift;
bitmap_set(rb->clear_bmap, start >> shift, clear_bmap_size(npages, shift));
}
/**
* clear_bmap_test_and_clear: test clear bitmap for the page, clear if set.
* Must be with bitmap_mutex held.
*
* @rb: the ramblock to operate on
* @page: the page number to check
*
* Returns: true if the bit was set, false otherwise
*/
static inline bool clear_bmap_test_and_clear(RAMBlock *rb, uint64_t page)
{
uint8_t shift = rb->clear_bmap_shift;
return bitmap_test_and_clear(rb->clear_bmap, page >> shift, 1);
}
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: RamBlock flags. Supported flags: RAM_SHARED, RAM_PMEM,
* RAM_NORESERVE.
* @mem_path or @fd: specify the backing file or device
* @readonly: true to open @path for reading, false for read/write.
* @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,
bool readonly, Error **errp);
RAMBlock *qemu_ram_alloc_from_fd(ram_addr_t size, MemoryRegion *mr,
uint32_t ram_flags, int fd, off_t offset,
bool readonly, 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, uint32_t ram_flags, 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);
void qemu_ram_msync(RAMBlock *block, ram_addr_t start, ram_addr_t length);
/* Clear whole block of mem */
static inline void qemu_ram_block_writeback(RAMBlock *block)
{
qemu_ram_msync(block, 0, block->used_length);
}
#define DIRTY_CLIENTS_ALL ((1 << DIRTY_MEMORY_NUM) - 1)
#define DIRTY_CLIENTS_NOCODE (DIRTY_CLIENTS_ALL & ~(1 << DIRTY_MEMORY_CODE))
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;
WITH_RCU_READ_LOCK_GUARD() {
blocks = qatomic_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;
}
}
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_GUARD();
blocks = qatomic_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;
}
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_GUARD();
blocks = qatomic_rcu_read(&ram_list.dirty_memory[client]);
set_bit_atomic(offset, blocks->blocks[idx]);
}
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;
WITH_RCU_READ_LOCK_GUARD() {
for (i = 0; i < DIRTY_MEMORY_NUM; i++) {
blocks[i] = qatomic_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;
}
}
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 = qemu_real_host_page_size() / 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);
WITH_RCU_READ_LOCK_GUARD() {
for (i = 0; i < DIRTY_MEMORY_NUM; i++) {
blocks[i] =
qatomic_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]);
qatomic_or(&blocks[DIRTY_MEMORY_VGA][idx][offset], temp);
if (global_dirty_tracking) {
qatomic_or(
&blocks[DIRTY_MEMORY_MIGRATION][idx][offset],
temp);
if (unlikely(
global_dirty_tracking & GLOBAL_DIRTY_DIRTY_RATE)) {
total_dirty_pages += ctpopl(temp);
}
}
if (tcg_enabled()) {
qatomic_or(&blocks[DIRTY_MEMORY_CODE][idx][offset],
temp);
}
}
if (++offset >= BITS_TO_LONGS(DIRTY_MEMORY_BLOCK_SIZE)) {
offset = 0;
idx++;
}
}
}
xen_hvm_modified_memory(start, pages << TARGET_PAGE_BITS);
} else {
uint8_t clients = tcg_enabled() ? DIRTY_CLIENTS_ALL : DIRTY_CLIENTS_NOCODE;
if (!global_dirty_tracking) {
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]);
if (unlikely(global_dirty_tracking & GLOBAL_DIRTY_DIRTY_RATE)) {
total_dirty_pages += ctpopl(c);
}
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)
{
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 = qatomic_rcu_read(
&ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION])->blocks;
for (k = page; k < page + nr; k++) {
if (src[idx][offset]) {
unsigned long bits = qatomic_xchg(&src[idx][offset], 0);
unsigned long new_dirty;
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++;
}
}
if (rb->clear_bmap) {
/*
* Postpone the dirty bitmap clear to the point before we
* really send the pages, also we will split the clear
* dirty procedure into smaller chunks.
*/
clear_bmap_set(rb, start >> TARGET_PAGE_BITS,
length >> TARGET_PAGE_BITS);
} else {
/* Slow path - still do that in a huge chunk */
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)) {
long k = (start + addr) >> TARGET_PAGE_BITS;
if (!test_and_set_bit(k, dest)) {
num_dirty++;
}
}
}
}
return num_dirty;
}
#endif
#endif