[Qemu-devel] [RFC 06/19] fuzz: Add ramfile for fast vmstate/vmload

[Oleinik, Alexander]

The ramfile allows vmstate to be saved and restored directly onto the
heap.

Signed-off-by: Alexander Oleinik <address@hidden>
---
 tests/fuzz/ramfile.c | 127 +++++++++++++++++++++++++++++++++++++++++++
 tests/fuzz/ramfile.h |  20 +++++++
 2 files changed, 147 insertions(+)
 create mode 100644 tests/fuzz/ramfile.c
 create mode 100644 tests/fuzz/ramfile.h

diff --git a/tests/fuzz/ramfile.c b/tests/fuzz/ramfile.c
new file mode 100644
index 0000000000..8da242e9ee
--- /dev/null
+++ b/tests/fuzz/ramfile.c
@@ -0,0 +1,127 @@
+/*
+ * 
=====================================================================================
+ *
+ *       Filename:  ramfile.c
+ *
+ *    Description:  QEMUFile stored in dynamically allocated RAM for fast 
VMRestore
+ *
+ *         Author:  Alexander Oleinik (), address@hidden
+ *   Organization:  
+ *
+ * 
=====================================================================================
+ */
+#include <stdlib.h>
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "exec/memory.h"
+#include "migration/qemu-file.h"
+#include "migration/migration.h"
+#include "migration/savevm.h"
+#include "ramfile.h"
+
+#define INCREMENT 10240
+#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;
+};
+
+static ssize_t ram_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
+                                  int64_t pos)
+{
+       ram_disk *rd = (ram_disk*)opaque;
+       gsize newsize;
+       ssize_t total_size = 0;
+       int i;
+       if(!rd->base) {
+               rd->base = g_malloc(INCREMENT);
+               rd->len = INCREMENT;
+       }
+       for(i = 0; i< iovcnt; i++)
+       {
+               if(pos+iov[i].iov_len >= rd->len ){
+                       newsize = ((pos + iov[i].iov_len)/INCREMENT + 1) * 
INCREMENT;
+                       rd->base = g_realloc(rd->base, newsize);
+                       rd->len = newsize;
+               }
+               /* for(int j =0; j<iov[i].iov_len; j++){ */
+               /*      printf("%hhx",*((char*)iov[i].iov_base+j)); */
+               /* } */
+               memcpy(rd->base + pos, iov[i].iov_base, iov[i].iov_len);
+               pos += iov[i].iov_len;
+               total_size += iov[i].iov_len;
+       }
+       return total_size;
+}
+
+static ssize_t ram_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
+                                   size_t size)
+{
+       ram_disk *rd = (ram_disk*)opaque;
+       if(pos+size>rd->len){
+               if(rd->len-pos>=0){
+                       memcpy(buf, rd->base + pos, rd->len-pos);
+                       size = rd->len-pos;
+               }
+       }
+       else
+               memcpy(buf, rd->base + pos, size);
+       return size;
+}
+
+static int ram_fclose(void *opaque)
+{
+       return 0;
+}
+
+static const QEMUFileOps ram_read_ops = {
+    .get_buffer = ram_get_buffer,
+    .close =      ram_fclose
+};
+
+static const QEMUFileOps ram_write_ops = {
+    .writev_buffer = ram_writev_buffer,
+    .close =      ram_fclose
+};
+
+QEMUFile *qemu_fopen_ram(ram_disk **return_rd) {
+       ram_disk *rd = g_new0(ram_disk, 1);
+       *return_rd=rd;
+       return qemu_fopen_ops(rd, &ram_write_ops);
+}
+
+QEMUFile *qemu_fopen_ro_ram(ram_disk* rd) {
+    return qemu_fopen_ops(rd, &ram_read_ops);
+}
+
+void qemu_freopen_ro_ram(QEMUFile* f) {
+       void *rd = f->opaque;
+       f->bytes_xfer=0;
+       f->xfer_limit=0;
+       f->last_error=0;
+       f->iovcnt=0;
+       f->buf_index=0;
+       f->buf_size=0;
+       f->pos=0;
+       f->ops = &ram_read_ops;
+       f->opaque = rd;
+       return;
+}
diff --git a/tests/fuzz/ramfile.h b/tests/fuzz/ramfile.h
new file mode 100644
index 0000000000..b51cc72950
--- /dev/null
+++ b/tests/fuzz/ramfile.h
@@ -0,0 +1,20 @@
+#ifndef RAMFILE_H
+#define RAMFILE_H
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qemu/iov.h"
+#include "exec/memory.h"
+#include "exec/address-spaces.h"
+#include "migration/qemu-file.h"
+
+typedef struct ram_disk {
+       void *base;
+       gsize len;
+} ram_disk;
+
+QEMUFile *qemu_fopen_ram(ram_disk **rd);
+QEMUFile *qemu_fopen_ro_ram(ram_disk* rd);
+void qemu_freopen_ro_ram(QEMUFile* f);
+
+#endif
-- 
2.20.1