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Diffstat (limited to 'migration/multifd-zlib.c')
-rw-r--r--migration/multifd-zlib.c38
1 files changed, 30 insertions, 8 deletions
diff --git a/migration/multifd-zlib.c b/migration/multifd-zlib.c
index 3a7ae44485..18213a9513 100644
--- a/migration/multifd-zlib.c
+++ b/migration/multifd-zlib.c
@@ -27,6 +27,8 @@ struct zlib_data {
uint8_t *zbuff;
/* size of compressed buffer */
uint32_t zbuff_len;
+ /* uncompressed buffer of size qemu_target_page_size() */
+ uint8_t *buf;
};
/* Multifd zlib compression */
@@ -45,26 +47,38 @@ static int zlib_send_setup(MultiFDSendParams *p, Error **errp)
{
struct zlib_data *z = g_new0(struct zlib_data, 1);
z_stream *zs = &z->zs;
+ const char *err_msg;
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 %u: deflate init failed", p->id);
- return -1;
+ err_msg = "deflate init failed";
+ goto err_free_z;
}
/* This is the maxium size of the compressed buffer */
z->zbuff_len = compressBound(MULTIFD_PACKET_SIZE);
z->zbuff = g_try_malloc(z->zbuff_len);
if (!z->zbuff) {
- deflateEnd(&z->zs);
- g_free(z);
- error_setg(errp, "multifd %u: out of memory for zbuff", p->id);
- return -1;
+ err_msg = "out of memory for zbuff";
+ goto err_deflate_end;
+ }
+ z->buf = g_try_malloc(qemu_target_page_size());
+ if (!z->buf) {
+ err_msg = "out of memory for buf";
+ goto err_free_zbuff;
}
p->data = z;
return 0;
+
+err_free_zbuff:
+ g_free(z->zbuff);
+err_deflate_end:
+ deflateEnd(&z->zs);
+err_free_z:
+ g_free(z);
+ error_setg(errp, "multifd %u: %s", p->id, err_msg);
+ return -1;
}
/**
@@ -82,6 +96,8 @@ static void zlib_send_cleanup(MultiFDSendParams *p, Error **errp)
deflateEnd(&z->zs);
g_free(z->zbuff);
z->zbuff = NULL;
+ g_free(z->buf);
+ z->buf = NULL;
g_free(p->data);
p->data = NULL;
}
@@ -114,8 +130,14 @@ static int zlib_send_prepare(MultiFDSendParams *p, Error **errp)
flush = Z_SYNC_FLUSH;
}
+ /*
+ * Since the VM might be running, the page may be changing concurrently
+ * with compression. zlib does not guarantee that this is safe,
+ * therefore copy the page before calling deflate().
+ */
+ memcpy(z->buf, p->pages->block->host + p->normal[i], page_size);
zs->avail_in = page_size;
- zs->next_in = p->pages->block->host + p->normal[i];
+ zs->next_in = z->buf;
zs->avail_out = available;
zs->next_out = z->zbuff + out_size;