[PATCH RFC 4/9] qemu: Add a 'features' element to save image header and bump version
QEMU's new mapped-ram stream format [1] is incompatible with the
existing sequential format. In order to support the new format in
libvirt, a new 'features' element is added to the saved image header.
This element can be used now indicate the use of mapped-ram feature,
and provides a mechanism to support future save image features.
An older libvirt that is unaware of mapped-ram must not attempt to
open and restore a mapped-ram saved image. ATM, this can only be
done by bumping the save image version.
[1]
https://gitlab.com/qemu-project/qemu/-/blob/master/docs/devel/migration/m...
Signed-off-by: Jim Fehlig <jfehlig(a)suse.com>
---
src/qemu/qemu_saveimage.c | 7 +++++++
src/qemu/qemu_saveimage.h | 9 +++++++--
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/src/qemu/qemu_saveimage.c b/src/qemu/qemu_saveimage.c
index 018ab5a222..50fec33f54 100644
--- a/src/qemu/qemu_saveimage.c
+++ b/src/qemu/qemu_saveimage.c
@@ -74,6 +74,7 @@ qemuSaveImageBswapHeader(virQEMUSaveHeader *hdr)
hdr->was_running = GUINT32_SWAP_LE_BE(hdr->was_running);
hdr->compressed = GUINT32_SWAP_LE_BE(hdr->compressed);
hdr->cookieOffset = GUINT32_SWAP_LE_BE(hdr->cookieOffset);
+ hdr->features = GUINT32_SWAP_LE_BE(hdr->features);
}
@@ -637,6 +638,12 @@ qemuSaveImageOpen(virQEMUDriver *driver,
return -1;
}
+ if (header->features && header->features !=
QEMU_SAVE_FEATURE_MAPPED_RAM) {
+ virReportError(VIR_ERR_OPERATION_FAILED, "%s",
+ _("image contains unsupported features)"));
+ return -1;
+ }
+
if (header->cookieOffset)
xml_len = header->cookieOffset;
else
diff --git a/src/qemu/qemu_saveimage.h b/src/qemu/qemu_saveimage.h
index e541792153..9dd7de292d 100644
--- a/src/qemu/qemu_saveimage.h
+++ b/src/qemu/qemu_saveimage.h
@@ -28,10 +28,14 @@
*/
#define QEMU_SAVE_MAGIC "LibvirtQemudSave"
#define QEMU_SAVE_PARTIAL "LibvirtQemudPart"
-#define QEMU_SAVE_VERSION 2
+#define QEMU_SAVE_VERSION 3
G_STATIC_ASSERT(sizeof(QEMU_SAVE_MAGIC) == sizeof(QEMU_SAVE_PARTIAL));
+typedef enum {
+ QEMU_SAVE_FEATURE_MAPPED_RAM = 1 << 0,
+} qemuSaveFeatures;
+
typedef struct _virQEMUSaveHeader virQEMUSaveHeader;
struct _virQEMUSaveHeader {
char magic[sizeof(QEMU_SAVE_MAGIC)-1];
@@ -40,7 +44,8 @@ struct _virQEMUSaveHeader {
uint32_t was_running;
uint32_t compressed;
uint32_t cookieOffset;
- uint32_t unused[14];
+ uint32_t features;
+ uint32_t unused[13];
};
--
2.44.0