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authorStefano Stabellini <stefano.stabellini@eu.citrix.com>2012-01-25 12:24:51 +0000
committerStefano Stabellini <stefano.stabellini@eu.citrix.com>2012-03-19 18:21:00 +0000
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tree64938ef20cc12726b5d229621c43ebe6cf40e462 /docs
parent695bb854e88be20756d5e509e02e28f94528b776 (diff)
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Introduce "xen-save-devices-state"
- add an "is_ram" flag to SaveStateEntry; - register_savevm_live sets is_ram for live_savevm devices; - introduce a "xen-save-devices-state" QAPI command that can be used to save the state of all devices, but not the RAM or the block devices of the VM. Changes in v8: - rename save-devices-state to xen-save-devices-state. Changes in v7: - rename save_devices to save-devices-state. Changes in v6: - remove the is_ram parameter from register_savevm_live and sets is_ram if the device is a live_savevm device; - introduce save_devices as a QAPI command, write a better description for it; - fix CODING_STYLE; - introduce a new doc to explain the save format used by save_devices. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Reviewed-by: Anthony Liguori <aliguori@us.ibm.com> Acked-by: Luiz Capitulino <lcapitulino@redhat.com>
Diffstat (limited to 'docs')
-rw-r--r--docs/xen-save-devices-state.txt34
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+= Save Devices =
+
+QEMU has code to load/save the state of the guest that it is running.
+These are two complementary operations. Saving the state just does
+that, saves the state for each device that the guest is running.
+
+These operations are normally used with migration (see migration.txt),
+however it is also possible to save the state of all devices to file,
+without saving the RAM or the block devices of the VM.
+
+This operation is called "xen-save-devices-state" (see
+QMP/qmp-commands.txt)
+
+
+The binary format used in the file is the following:
+
+
+-------------------------------------------
+
+32 bit big endian: QEMU_VM_FILE_MAGIC
+32 bit big endian: QEMU_VM_FILE_VERSION
+
+for_each_device
+{
+ 8 bit: QEMU_VM_SECTION_FULL
+ 32 bit big endian: section_id
+ 8 bit: idstr (ID string) length
+ string: idstr (ID string)
+ 32 bit big endian: instance_id
+ 32 bit big endian: version_id
+ buffer: device specific data
+}
+
+8 bit: QEMU_VM_EOF