Re: [Qemu-devel] [RFC 06/19] fuzz: Add ramfile for fast vmstate/vmload
On 26/07/19 21:36, Oleinik, Alexander wrote: >> >> Please add the ram file to qemu-file.c instead of duplicating QEMUFile. >> > I think we should be able to replace all of this simply by using > memfd_create. Since it acts as a regular file, it will work with the > existing code (likely with performance gains). That wouldn't be portable to non-Linux, so having RAMFile is better. Paolo
Re: [Qemu-devel] [RFC 06/19] fuzz: Add ramfile for fast vmstate/vmload
On 7/26/19 8:47 AM, Stefan Hajnoczi wrote:
> On Thu, Jul 25, 2019 at 03:23:49AM +, Oleinik, Alexander wrote:
>> The ramfile allows vmstate to be saved and restored directly onto the
>> heap.
>>
>> Signed-off-by: Alexander Oleinik
>> ---
>> 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 00..8da242e9ee
>> --- /dev/null
>> +++ b/tests/fuzz/ramfile.c
>
> Please put this in migration/. This code doesn't do fuzzing and is
> general-purpose enough to be used by other parts of QEMU dealing with
> live migration.
>
>> @@ -0,0 +1,127 @@
>> +/*
>> + *
>> =
>> + *
>> + * Filename: ramfile.c
>> + *
>> + *Description: QEMUFile stored in dynamically allocated RAM for fast
>> VMRestore
>> + *
>> + * Author: Alexander Oleinik (), alx...@bu.edu
>> + * Organization:
>> + *
>> + *
>> =
>> + */
>
> Please use license headers with all new files that are created.
> Fine-grained filename and authorship information is already kept by git
> so it's not necessary to duplicate it here.
>
>> +#include
>> +#include "qemu/osdep.h"
>
> osdep.h already includes stdlib.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;
>> +};
>
> Wait, what?! :)
>
> Please add the ram file to qemu-file.c instead of duplicating QEMUFile.
>
I think we should be able to replace all of this simply by using
memfd_create. Since it acts as a regular file, it will work with the
existing code (likely with performance gains).
Re: [Qemu-devel] [RFC 06/19] fuzz: Add ramfile for fast vmstate/vmload
On Thu, Jul 25, 2019 at 03:23:49AM +, Oleinik, Alexander wrote:
> The ramfile allows vmstate to be saved and restored directly onto the
> heap.
>
> Signed-off-by: Alexander Oleinik
> ---
> 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 00..8da242e9ee
> --- /dev/null
> +++ b/tests/fuzz/ramfile.c
Please put this in migration/. This code doesn't do fuzzing and is
general-purpose enough to be used by other parts of QEMU dealing with
live migration.
> @@ -0,0 +1,127 @@
> +/*
> + *
> =
> + *
> + * Filename: ramfile.c
> + *
> + *Description: QEMUFile stored in dynamically allocated RAM for fast
> VMRestore
> + *
> + * Author: Alexander Oleinik (), alx...@bu.edu
> + * Organization:
> + *
> + *
> =
> + */
Please use license headers with all new files that are created.
Fine-grained filename and authorship information is already kept by git
so it's not necessary to duplicate it here.
> +#include
> +#include "qemu/osdep.h"
osdep.h already includes stdlib.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;
> +};
Wait, what?! :)
Please add the ram file to qemu-file.c instead of duplicating QEMUFile.
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Description: PGP signature
[Qemu-devel] [RFC 06/19] fuzz: Add ramfile for fast vmstate/vmload
The ramfile allows vmstate to be saved and restored directly onto the
heap.
Signed-off-by: Alexander Oleinik
---
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 00..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 (), alx...@bu.edu
+ * Organization:
+ *
+ *
=
+ */
+#include
+#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; jbase + 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, _write_ops);
+}
+
+QEMUFile *qemu_fopen_ro_ram(ram_disk* rd) {
+return qemu_fopen_ops(rd, _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 = _read_ops;
+ f->opaque = rd;
+ return;
+}
diff --git a/tests/fuzz/ramfile.h b/tests/fuzz/ramfile.h
new file mode 100644
index 00..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
