qemu/migration/qemu-file.c
Lidong Chen ccb7e1b5a6 migration: disable RDMA WRITE after postcopy started
RDMA WRITE operations are performed with no notification to the destination
qemu, then the destination qemu can not wakeup. This patch disable RDMA WRITE
after postcopy started.

Signed-off-by: Lidong Chen <lidongchen@tencent.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2018-08-22 12:12:07 +02:00

790 lines
19 KiB
C

/*
* QEMU System Emulator
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include <zlib.h>
#include "qemu-common.h"
#include "qemu/error-report.h"
#include "qemu/iov.h"
#include "migration.h"
#include "qemu-file.h"
#include "trace.h"
#define IO_BUF_SIZE 32768
#define MAX_IOV_SIZE MIN(IOV_MAX, 64)
struct QEMUFile {
const QEMUFileOps *ops;
const QEMUFileHooks *hooks;
void *opaque;
int64_t bytes_xfer;
int64_t xfer_limit;
int64_t pos; /* start of buffer when writing, end of buffer
when reading */
int buf_index;
int buf_size; /* 0 when writing */
uint8_t buf[IO_BUF_SIZE];
DECLARE_BITMAP(may_free, MAX_IOV_SIZE);
struct iovec iov[MAX_IOV_SIZE];
unsigned int iovcnt;
int last_error;
};
/*
* Stop a file from being read/written - not all backing files can do this
* typically only sockets can.
*/
int qemu_file_shutdown(QEMUFile *f)
{
if (!f->ops->shut_down) {
return -ENOSYS;
}
return f->ops->shut_down(f->opaque, true, true);
}
/*
* Result: QEMUFile* for a 'return path' for comms in the opposite direction
* NULL if not available
*/
QEMUFile *qemu_file_get_return_path(QEMUFile *f)
{
if (!f->ops->get_return_path) {
return NULL;
}
return f->ops->get_return_path(f->opaque);
}
bool qemu_file_mode_is_not_valid(const char *mode)
{
if (mode == NULL ||
(mode[0] != 'r' && mode[0] != 'w') ||
mode[1] != 'b' || mode[2] != 0) {
fprintf(stderr, "qemu_fopen: Argument validity check failed\n");
return true;
}
return false;
}
QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops)
{
QEMUFile *f;
f = g_new0(QEMUFile, 1);
f->opaque = opaque;
f->ops = ops;
return f;
}
void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks)
{
f->hooks = hooks;
}
/*
* Get last error for stream f
*
* Return negative error value if there has been an error on previous
* operations, return 0 if no error happened.
*
*/
int qemu_file_get_error(QEMUFile *f)
{
return f->last_error;
}
void qemu_file_set_error(QEMUFile *f, int ret)
{
if (f->last_error == 0) {
f->last_error = ret;
}
}
bool qemu_file_is_writable(QEMUFile *f)
{
return f->ops->writev_buffer;
}
static void qemu_iovec_release_ram(QEMUFile *f)
{
struct iovec iov;
unsigned long idx;
/* Find and release all the contiguous memory ranges marked as may_free. */
idx = find_next_bit(f->may_free, f->iovcnt, 0);
if (idx >= f->iovcnt) {
return;
}
iov = f->iov[idx];
/* The madvise() in the loop is called for iov within a continuous range and
* then reinitialize the iov. And in the end, madvise() is called for the
* last iov.
*/
while ((idx = find_next_bit(f->may_free, f->iovcnt, idx + 1)) < f->iovcnt) {
/* check for adjacent buffer and coalesce them */
if (iov.iov_base + iov.iov_len == f->iov[idx].iov_base) {
iov.iov_len += f->iov[idx].iov_len;
continue;
}
if (qemu_madvise(iov.iov_base, iov.iov_len, QEMU_MADV_DONTNEED) < 0) {
error_report("migrate: madvise DONTNEED failed %p %zd: %s",
iov.iov_base, iov.iov_len, strerror(errno));
}
iov = f->iov[idx];
}
if (qemu_madvise(iov.iov_base, iov.iov_len, QEMU_MADV_DONTNEED) < 0) {
error_report("migrate: madvise DONTNEED failed %p %zd: %s",
iov.iov_base, iov.iov_len, strerror(errno));
}
memset(f->may_free, 0, sizeof(f->may_free));
}
/**
* Flushes QEMUFile buffer
*
* If there is writev_buffer QEMUFileOps it uses it otherwise uses
* put_buffer ops. This will flush all pending data. If data was
* only partially flushed, it will set an error state.
*/
void qemu_fflush(QEMUFile *f)
{
ssize_t ret = 0;
ssize_t expect = 0;
if (!qemu_file_is_writable(f)) {
return;
}
if (f->iovcnt > 0) {
expect = iov_size(f->iov, f->iovcnt);
ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt, f->pos);
qemu_iovec_release_ram(f);
}
if (ret >= 0) {
f->pos += ret;
}
/* We expect the QEMUFile write impl to send the full
* data set we requested, so sanity check that.
*/
if (ret != expect) {
qemu_file_set_error(f, ret < 0 ? ret : -EIO);
}
f->buf_index = 0;
f->iovcnt = 0;
}
void ram_control_before_iterate(QEMUFile *f, uint64_t flags)
{
int ret = 0;
if (f->hooks && f->hooks->before_ram_iterate) {
ret = f->hooks->before_ram_iterate(f, f->opaque, flags, NULL);
if (ret < 0) {
qemu_file_set_error(f, ret);
}
}
}
void ram_control_after_iterate(QEMUFile *f, uint64_t flags)
{
int ret = 0;
if (f->hooks && f->hooks->after_ram_iterate) {
ret = f->hooks->after_ram_iterate(f, f->opaque, flags, NULL);
if (ret < 0) {
qemu_file_set_error(f, ret);
}
}
}
void ram_control_load_hook(QEMUFile *f, uint64_t flags, void *data)
{
int ret = -EINVAL;
if (f->hooks && f->hooks->hook_ram_load) {
ret = f->hooks->hook_ram_load(f, f->opaque, flags, data);
if (ret < 0) {
qemu_file_set_error(f, ret);
}
} else {
/*
* Hook is a hook specifically requested by the source sending a flag
* that expects there to be a hook on the destination.
*/
if (flags == RAM_CONTROL_HOOK) {
qemu_file_set_error(f, ret);
}
}
}
size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
ram_addr_t offset, size_t size,
uint64_t *bytes_sent)
{
if (f->hooks && f->hooks->save_page) {
int ret = f->hooks->save_page(f, f->opaque, block_offset,
offset, size, bytes_sent);
if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {
f->bytes_xfer += size;
}
if (ret != RAM_SAVE_CONTROL_DELAYED &&
ret != RAM_SAVE_CONTROL_NOT_SUPP) {
if (bytes_sent && *bytes_sent > 0) {
qemu_update_position(f, *bytes_sent);
} else if (ret < 0) {
qemu_file_set_error(f, ret);
}
}
return ret;
}
return RAM_SAVE_CONTROL_NOT_SUPP;
}
/*
* Attempt to fill the buffer from the underlying file
* Returns the number of bytes read, or negative value for an error.
*
* Note that it can return a partially full buffer even in a not error/not EOF
* case if the underlying file descriptor gives a short read, and that can
* happen even on a blocking fd.
*/
static ssize_t qemu_fill_buffer(QEMUFile *f)
{
int len;
int pending;
assert(!qemu_file_is_writable(f));
pending = f->buf_size - f->buf_index;
if (pending > 0) {
memmove(f->buf, f->buf + f->buf_index, pending);
}
f->buf_index = 0;
f->buf_size = pending;
len = f->ops->get_buffer(f->opaque, f->buf + pending, f->pos,
IO_BUF_SIZE - pending);
if (len > 0) {
f->buf_size += len;
f->pos += len;
} else if (len == 0) {
qemu_file_set_error(f, -EIO);
} else if (len != -EAGAIN) {
qemu_file_set_error(f, len);
}
return len;
}
void qemu_update_position(QEMUFile *f, size_t size)
{
f->pos += size;
}
/** Closes the file
*
* Returns negative error value if any error happened on previous operations or
* while closing the file. Returns 0 or positive number on success.
*
* The meaning of return value on success depends on the specific backend
* being used.
*/
int qemu_fclose(QEMUFile *f)
{
int ret;
qemu_fflush(f);
ret = qemu_file_get_error(f);
if (f->ops->close) {
int ret2 = f->ops->close(f->opaque);
if (ret >= 0) {
ret = ret2;
}
}
/* If any error was spotted before closing, we should report it
* instead of the close() return value.
*/
if (f->last_error) {
ret = f->last_error;
}
g_free(f);
trace_qemu_file_fclose();
return ret;
}
static void add_to_iovec(QEMUFile *f, const uint8_t *buf, size_t size,
bool may_free)
{
/* check for adjacent buffer and coalesce them */
if (f->iovcnt > 0 && buf == f->iov[f->iovcnt - 1].iov_base +
f->iov[f->iovcnt - 1].iov_len &&
may_free == test_bit(f->iovcnt - 1, f->may_free))
{
f->iov[f->iovcnt - 1].iov_len += size;
} else {
if (may_free) {
set_bit(f->iovcnt, f->may_free);
}
f->iov[f->iovcnt].iov_base = (uint8_t *)buf;
f->iov[f->iovcnt++].iov_len = size;
}
if (f->iovcnt >= MAX_IOV_SIZE) {
qemu_fflush(f);
}
}
void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, size_t size,
bool may_free)
{
if (f->last_error) {
return;
}
f->bytes_xfer += size;
add_to_iovec(f, buf, size, may_free);
}
void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, size_t size)
{
size_t l;
if (f->last_error) {
return;
}
while (size > 0) {
l = IO_BUF_SIZE - f->buf_index;
if (l > size) {
l = size;
}
memcpy(f->buf + f->buf_index, buf, l);
f->bytes_xfer += l;
add_to_iovec(f, f->buf + f->buf_index, l, false);
f->buf_index += l;
if (f->buf_index == IO_BUF_SIZE) {
qemu_fflush(f);
}
if (qemu_file_get_error(f)) {
break;
}
buf += l;
size -= l;
}
}
void qemu_put_byte(QEMUFile *f, int v)
{
if (f->last_error) {
return;
}
f->buf[f->buf_index] = v;
f->bytes_xfer++;
add_to_iovec(f, f->buf + f->buf_index, 1, false);
f->buf_index++;
if (f->buf_index == IO_BUF_SIZE) {
qemu_fflush(f);
}
}
void qemu_file_skip(QEMUFile *f, int size)
{
if (f->buf_index + size <= f->buf_size) {
f->buf_index += size;
}
}
/*
* Read 'size' bytes from file (at 'offset') without moving the
* pointer and set 'buf' to point to that data.
*
* It will return size bytes unless there was an error, in which case it will
* return as many as it managed to read (assuming blocking fd's which
* all current QEMUFile are)
*/
size_t qemu_peek_buffer(QEMUFile *f, uint8_t **buf, size_t size, size_t offset)
{
ssize_t pending;
size_t index;
assert(!qemu_file_is_writable(f));
assert(offset < IO_BUF_SIZE);
assert(size <= IO_BUF_SIZE - offset);
/* The 1st byte to read from */
index = f->buf_index + offset;
/* The number of available bytes starting at index */
pending = f->buf_size - index;
/*
* qemu_fill_buffer might return just a few bytes, even when there isn't
* an error, so loop collecting them until we get enough.
*/
while (pending < size) {
int received = qemu_fill_buffer(f);
if (received <= 0) {
break;
}
index = f->buf_index + offset;
pending = f->buf_size - index;
}
if (pending <= 0) {
return 0;
}
if (size > pending) {
size = pending;
}
*buf = f->buf + index;
return size;
}
/*
* Read 'size' bytes of data from the file into buf.
* 'size' can be larger than the internal buffer.
*
* It will return size bytes unless there was an error, in which case it will
* return as many as it managed to read (assuming blocking fd's which
* all current QEMUFile are)
*/
size_t qemu_get_buffer(QEMUFile *f, uint8_t *buf, size_t size)
{
size_t pending = size;
size_t done = 0;
while (pending > 0) {
size_t res;
uint8_t *src;
res = qemu_peek_buffer(f, &src, MIN(pending, IO_BUF_SIZE), 0);
if (res == 0) {
return done;
}
memcpy(buf, src, res);
qemu_file_skip(f, res);
buf += res;
pending -= res;
done += res;
}
return done;
}
/*
* Read 'size' bytes of data from the file.
* 'size' can be larger than the internal buffer.
*
* The data:
* may be held on an internal buffer (in which case *buf is updated
* to point to it) that is valid until the next qemu_file operation.
* OR
* will be copied to the *buf that was passed in.
*
* The code tries to avoid the copy if possible.
*
* It will return size bytes unless there was an error, in which case it will
* return as many as it managed to read (assuming blocking fd's which
* all current QEMUFile are)
*
* Note: Since **buf may get changed, the caller should take care to
* keep a pointer to the original buffer if it needs to deallocate it.
*/
size_t qemu_get_buffer_in_place(QEMUFile *f, uint8_t **buf, size_t size)
{
if (size < IO_BUF_SIZE) {
size_t res;
uint8_t *src;
res = qemu_peek_buffer(f, &src, size, 0);
if (res == size) {
qemu_file_skip(f, res);
*buf = src;
return res;
}
}
return qemu_get_buffer(f, *buf, size);
}
/*
* Peeks a single byte from the buffer; this isn't guaranteed to work if
* offset leaves a gap after the previous read/peeked data.
*/
int qemu_peek_byte(QEMUFile *f, int offset)
{
int index = f->buf_index + offset;
assert(!qemu_file_is_writable(f));
assert(offset < IO_BUF_SIZE);
if (index >= f->buf_size) {
qemu_fill_buffer(f);
index = f->buf_index + offset;
if (index >= f->buf_size) {
return 0;
}
}
return f->buf[index];
}
int qemu_get_byte(QEMUFile *f)
{
int result;
result = qemu_peek_byte(f, 0);
qemu_file_skip(f, 1);
return result;
}
int64_t qemu_ftell_fast(QEMUFile *f)
{
int64_t ret = f->pos;
int i;
for (i = 0; i < f->iovcnt; i++) {
ret += f->iov[i].iov_len;
}
return ret;
}
int64_t qemu_ftell(QEMUFile *f)
{
qemu_fflush(f);
return f->pos;
}
int qemu_file_rate_limit(QEMUFile *f)
{
if (qemu_file_get_error(f)) {
return 1;
}
if (f->xfer_limit > 0 && f->bytes_xfer > f->xfer_limit) {
return 1;
}
return 0;
}
int64_t qemu_file_get_rate_limit(QEMUFile *f)
{
return f->xfer_limit;
}
void qemu_file_set_rate_limit(QEMUFile *f, int64_t limit)
{
f->xfer_limit = limit;
}
void qemu_file_reset_rate_limit(QEMUFile *f)
{
f->bytes_xfer = 0;
}
void qemu_put_be16(QEMUFile *f, unsigned int v)
{
qemu_put_byte(f, v >> 8);
qemu_put_byte(f, v);
}
void qemu_put_be32(QEMUFile *f, unsigned int v)
{
qemu_put_byte(f, v >> 24);
qemu_put_byte(f, v >> 16);
qemu_put_byte(f, v >> 8);
qemu_put_byte(f, v);
}
void qemu_put_be64(QEMUFile *f, uint64_t v)
{
qemu_put_be32(f, v >> 32);
qemu_put_be32(f, v);
}
unsigned int qemu_get_be16(QEMUFile *f)
{
unsigned int v;
v = qemu_get_byte(f) << 8;
v |= qemu_get_byte(f);
return v;
}
unsigned int qemu_get_be32(QEMUFile *f)
{
unsigned int v;
v = (unsigned int)qemu_get_byte(f) << 24;
v |= qemu_get_byte(f) << 16;
v |= qemu_get_byte(f) << 8;
v |= qemu_get_byte(f);
return v;
}
uint64_t qemu_get_be64(QEMUFile *f)
{
uint64_t v;
v = (uint64_t)qemu_get_be32(f) << 32;
v |= qemu_get_be32(f);
return v;
}
/* return the size after compression, or negative value on error */
static int qemu_compress_data(z_stream *stream, uint8_t *dest, size_t dest_len,
const uint8_t *source, size_t source_len)
{
int err;
err = deflateReset(stream);
if (err != Z_OK) {
return -1;
}
stream->avail_in = source_len;
stream->next_in = (uint8_t *)source;
stream->avail_out = dest_len;
stream->next_out = dest;
err = deflate(stream, Z_FINISH);
if (err != Z_STREAM_END) {
return -1;
}
return stream->next_out - dest;
}
/* Compress size bytes of data start at p and store the compressed
* data to the buffer of f.
*
* When f is not writable, return -1 if f has no space to save the
* compressed data.
* When f is wirtable and it has no space to save the compressed data,
* do fflush first, if f still has no space to save the compressed
* data, return -1.
*/
ssize_t qemu_put_compression_data(QEMUFile *f, z_stream *stream,
const uint8_t *p, size_t size)
{
ssize_t blen = IO_BUF_SIZE - f->buf_index - sizeof(int32_t);
if (blen < compressBound(size)) {
if (!qemu_file_is_writable(f)) {
return -1;
}
qemu_fflush(f);
blen = IO_BUF_SIZE - sizeof(int32_t);
if (blen < compressBound(size)) {
return -1;
}
}
blen = qemu_compress_data(stream, f->buf + f->buf_index + sizeof(int32_t),
blen, p, size);
if (blen < 0) {
return -1;
}
qemu_put_be32(f, blen);
if (f->ops->writev_buffer) {
add_to_iovec(f, f->buf + f->buf_index, blen, false);
}
f->buf_index += blen;
if (f->buf_index == IO_BUF_SIZE) {
qemu_fflush(f);
}
return blen + sizeof(int32_t);
}
/* Put the data in the buffer of f_src to the buffer of f_des, and
* then reset the buf_index of f_src to 0.
*/
int qemu_put_qemu_file(QEMUFile *f_des, QEMUFile *f_src)
{
int len = 0;
if (f_src->buf_index > 0) {
len = f_src->buf_index;
qemu_put_buffer(f_des, f_src->buf, f_src->buf_index);
f_src->buf_index = 0;
f_src->iovcnt = 0;
}
return len;
}
/*
* Get a string whose length is determined by a single preceding byte
* A preallocated 256 byte buffer must be passed in.
* Returns: len on success and a 0 terminated string in the buffer
* else 0
* (Note a 0 length string will return 0 either way)
*/
size_t qemu_get_counted_string(QEMUFile *f, char buf[256])
{
size_t len = qemu_get_byte(f);
size_t res = qemu_get_buffer(f, (uint8_t *)buf, len);
buf[res] = 0;
return res == len ? res : 0;
}
/*
* Put a string with one preceding byte containing its length. The length of
* the string should be less than 256.
*/
void qemu_put_counted_string(QEMUFile *f, const char *str)
{
size_t len = strlen(str);
assert(len < 256);
qemu_put_byte(f, len);
qemu_put_buffer(f, (const uint8_t *)str, len);
}
/*
* Set the blocking state of the QEMUFile.
* Note: On some transports the OS only keeps a single blocking state for
* both directions, and thus changing the blocking on the main
* QEMUFile can also affect the return path.
*/
void qemu_file_set_blocking(QEMUFile *f, bool block)
{
if (f->ops->set_blocking) {
f->ops->set_blocking(f->opaque, block);
}
}