multifd: Add zlib compression multifd support
Signed-off-by: Juan Quintela <quintela@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
diff --git a/migration/multifd-zlib.c b/migration/multifd-zlib.c
new file mode 100644
index 0000000..ab4ba75
--- /dev/null
+++ b/migration/multifd-zlib.c
@@ -0,0 +1,325 @@
+/*
+ * Multifd zlib compression implementation
+ *
+ * Copyright (c) 2020 Red Hat Inc
+ *
+ * Authors:
+ * Juan Quintela <quintela@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.
+ */
+
+#include "qemu/osdep.h"
+#include <zlib.h>
+#include "qemu/rcu.h"
+#include "exec/target_page.h"
+#include "qapi/error.h"
+#include "migration.h"
+#include "trace.h"
+#include "multifd.h"
+
+struct zlib_data {
+ /* stream for compression */
+ z_stream zs;
+ /* compressed buffer */
+ uint8_t *zbuff;
+ /* size of compressed buffer */
+ uint32_t zbuff_len;
+};
+
+/* Multifd zlib compression */
+
+/**
+ * zlib_send_setup: setup send side
+ *
+ * Setup each channel with zlib compression.
+ *
+ * Returns 0 for success or -1 for error
+ *
+ * @p: Params for the channel that we are using
+ * @errp: pointer to an error
+ */
+static int zlib_send_setup(MultiFDSendParams *p, Error **errp)
+{
+ uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
+ struct zlib_data *z = g_malloc0(sizeof(struct zlib_data));
+ z_stream *zs = &z->zs;
+
+ zs->zalloc = Z_NULL;
+ zs->zfree = Z_NULL;
+ zs->opaque = Z_NULL;
+ if (deflateInit(zs, migrate_multifd_zlib_level()) != Z_OK) {
+ g_free(z);
+ error_setg(errp, "multifd %d: deflate init failed", p->id);
+ return -1;
+ }
+ /* We will never have more than page_count pages */
+ z->zbuff_len = page_count * qemu_target_page_size();
+ z->zbuff_len *= 2;
+ z->zbuff = g_try_malloc(z->zbuff_len);
+ if (!z->zbuff) {
+ deflateEnd(&z->zs);
+ g_free(z);
+ error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
+ return -1;
+ }
+ p->data = z;
+ return 0;
+}
+
+/**
+ * zlib_send_cleanup: cleanup send side
+ *
+ * Close the channel and return memory.
+ *
+ * @p: Params for the channel that we are using
+ */
+static void zlib_send_cleanup(MultiFDSendParams *p, Error **errp)
+{
+ struct zlib_data *z = p->data;
+
+ deflateEnd(&z->zs);
+ g_free(z->zbuff);
+ z->zbuff = NULL;
+ g_free(p->data);
+ p->data = NULL;
+}
+
+/**
+ * zlib_send_prepare: prepare date to be able to send
+ *
+ * Create a compressed buffer with all the pages that we are going to
+ * send.
+ *
+ * Returns 0 for success or -1 for error
+ *
+ * @p: Params for the channel that we are using
+ * @used: number of pages used
+ */
+static int zlib_send_prepare(MultiFDSendParams *p, uint32_t used, Error **errp)
+{
+ struct iovec *iov = p->pages->iov;
+ struct zlib_data *z = p->data;
+ z_stream *zs = &z->zs;
+ uint32_t out_size = 0;
+ int ret;
+ uint32_t i;
+
+ for (i = 0; i < used; i++) {
+ uint32_t available = z->zbuff_len - out_size;
+ int flush = Z_NO_FLUSH;
+
+ if (i == used - 1) {
+ flush = Z_SYNC_FLUSH;
+ }
+
+ zs->avail_in = iov[i].iov_len;
+ zs->next_in = iov[i].iov_base;
+
+ zs->avail_out = available;
+ zs->next_out = z->zbuff + out_size;
+
+ /*
+ * Welcome to deflate semantics
+ *
+ * We need to loop while:
+ * - return is Z_OK
+ * - there are stuff to be compressed
+ * - there are output space free
+ */
+ do {
+ ret = deflate(zs, flush);
+ } while (ret == Z_OK && zs->avail_in && zs->avail_out);
+ if (ret == Z_OK && zs->avail_in) {
+ error_setg(errp, "multifd %d: deflate failed to compress all input",
+ p->id);
+ return -1;
+ }
+ if (ret != Z_OK) {
+ error_setg(errp, "multifd %d: deflate returned %d instead of Z_OK",
+ p->id, ret);
+ return -1;
+ }
+ out_size += available - zs->avail_out;
+ }
+ p->next_packet_size = out_size;
+ p->flags |= MULTIFD_FLAG_ZLIB;
+
+ return 0;
+}
+
+/**
+ * zlib_send_write: do the actual write of the data
+ *
+ * Do the actual write of the comprresed buffer.
+ *
+ * Returns 0 for success or -1 for error
+ *
+ * @p: Params for the channel that we are using
+ * @used: number of pages used
+ * @errp: pointer to an error
+ */
+static int zlib_send_write(MultiFDSendParams *p, uint32_t used, Error **errp)
+{
+ struct zlib_data *z = p->data;
+
+ return qio_channel_write_all(p->c, (void *)z->zbuff, p->next_packet_size,
+ errp);
+}
+
+/**
+ * zlib_recv_setup: setup receive side
+ *
+ * Create the compressed channel and buffer.
+ *
+ * Returns 0 for success or -1 for error
+ *
+ * @p: Params for the channel that we are using
+ * @errp: pointer to an error
+ */
+static int zlib_recv_setup(MultiFDRecvParams *p, Error **errp)
+{
+ uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
+ struct zlib_data *z = g_malloc0(sizeof(struct zlib_data));
+ z_stream *zs = &z->zs;
+
+ p->data = z;
+ zs->zalloc = Z_NULL;
+ zs->zfree = Z_NULL;
+ zs->opaque = Z_NULL;
+ zs->avail_in = 0;
+ zs->next_in = Z_NULL;
+ if (inflateInit(zs) != Z_OK) {
+ error_setg(errp, "multifd %d: inflate init failed", p->id);
+ return -1;
+ }
+ /* We will never have more than page_count pages */
+ z->zbuff_len = page_count * qemu_target_page_size();
+ /* We know compression "could" use more space */
+ z->zbuff_len *= 2;
+ z->zbuff = g_try_malloc(z->zbuff_len);
+ if (!z->zbuff) {
+ inflateEnd(zs);
+ error_setg(errp, "multifd %d: out of memory for zbuff", p->id);
+ return -1;
+ }
+ return 0;
+}
+
+/**
+ * zlib_recv_cleanup: setup receive side
+ *
+ * For no compression this function does nothing.
+ *
+ * @p: Params for the channel that we are using
+ */
+static void zlib_recv_cleanup(MultiFDRecvParams *p)
+{
+ struct zlib_data *z = p->data;
+
+ inflateEnd(&z->zs);
+ g_free(z->zbuff);
+ z->zbuff = NULL;
+ g_free(p->data);
+ p->data = NULL;
+}
+
+/**
+ * zlib_recv_pages: read the data from the channel into actual pages
+ *
+ * Read the compressed buffer, and uncompress it into the actual
+ * pages.
+ *
+ * Returns 0 for success or -1 for error
+ *
+ * @p: Params for the channel that we are using
+ * @used: number of pages used
+ * @errp: pointer to an error
+ */
+static int zlib_recv_pages(MultiFDRecvParams *p, uint32_t used, Error **errp)
+{
+ struct zlib_data *z = p->data;
+ z_stream *zs = &z->zs;
+ uint32_t in_size = p->next_packet_size;
+ /* we measure the change of total_out */
+ uint32_t out_size = zs->total_out;
+ uint32_t expected_size = used * qemu_target_page_size();
+ uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
+ int ret;
+ int i;
+
+ if (flags != MULTIFD_FLAG_ZLIB) {
+ error_setg(errp, "multifd %d: flags received %x flags expected %x",
+ p->id, flags, MULTIFD_FLAG_ZLIB);
+ return -1;
+ }
+ ret = qio_channel_read_all(p->c, (void *)z->zbuff, in_size, errp);
+
+ if (ret != 0) {
+ return ret;
+ }
+
+ zs->avail_in = in_size;
+ zs->next_in = z->zbuff;
+
+ for (i = 0; i < used; i++) {
+ struct iovec *iov = &p->pages->iov[i];
+ int flush = Z_NO_FLUSH;
+ unsigned long start = zs->total_out;
+
+ if (i == used - 1) {
+ flush = Z_SYNC_FLUSH;
+ }
+
+ zs->avail_out = iov->iov_len;
+ zs->next_out = iov->iov_base;
+
+ /*
+ * Welcome to inflate semantics
+ *
+ * We need to loop while:
+ * - return is Z_OK
+ * - there are input available
+ * - we haven't completed a full page
+ */
+ do {
+ ret = inflate(zs, flush);
+ } while (ret == Z_OK && zs->avail_in
+ && (zs->total_out - start) < iov->iov_len);
+ if (ret == Z_OK && (zs->total_out - start) < iov->iov_len) {
+ error_setg(errp, "multifd %d: inflate generated too few output",
+ p->id);
+ return -1;
+ }
+ if (ret != Z_OK) {
+ error_setg(errp, "multifd %d: inflate returned %d instead of Z_OK",
+ p->id, ret);
+ return -1;
+ }
+ }
+ out_size = zs->total_out - out_size;
+ if (out_size != expected_size) {
+ error_setg(errp, "multifd %d: packet size received %d size expected %d",
+ p->id, out_size, expected_size);
+ return -1;
+ }
+ return 0;
+}
+
+static MultiFDMethods multifd_zlib_ops = {
+ .send_setup = zlib_send_setup,
+ .send_cleanup = zlib_send_cleanup,
+ .send_prepare = zlib_send_prepare,
+ .send_write = zlib_send_write,
+ .recv_setup = zlib_recv_setup,
+ .recv_cleanup = zlib_recv_cleanup,
+ .recv_pages = zlib_recv_pages
+};
+
+static void multifd_zlib_register(void)
+{
+ multifd_register_ops(MULTIFD_COMPRESSION_ZLIB, &multifd_zlib_ops);
+}
+
+migration_init(multifd_zlib_register);
