[PATCH RFC 2/2] xen/kexec: Reserve KEXEC_TYPE_LIVEUPDATE and KEXEC_RANGE_MA_LIVEUPDATE

[Julien Grall <julien@xen.org>]

From: Julien Grall <jgrall@amazon.com>

Unfortunately, the code to support Live Update has already been merged in
Kexec and shipped since 2.0.21. Reserve the IDs used by Kexec before they
end up to be re-used for a different purpose.

This patch reserves two IDs:
    * KEXEC_TYPE_LIVEUPDATE: New operation to request Live Update
    * KEXEC_MA_RANGE_LIVEUPDATE: New range to query the Live Update
      area below Xen

Signed-off-by: Julien Grall <jgrall@amazon.com>
---
 xen/include/public/kexec.h | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/xen/include/public/kexec.h b/xen/include/public/kexec.h
index 3f2a118381ba..650d2feb036f 100644
--- a/xen/include/public/kexec.h
+++ b/xen/include/public/kexec.h
@@ -71,17 +71,22 @@
  */
 
 /*
- * Kexec supports two types of operation:
+ * Kexec supports three types of operation:
  * - kexec into a regular kernel, very similar to a standard reboot
  *   - KEXEC_TYPE_DEFAULT is used to specify this type
  * - kexec into a special "crash kernel", aka kexec-on-panic
  *   - KEXEC_TYPE_CRASH is used to specify this type
  *   - parts of our system may be broken at kexec-on-panic time
  *     - the code should be kept as simple and self-contained as possible
+ * - Live update into a new Xen, preserving all running domains
+ *   - KEXEC_TYPE_LIVE_UPDATE is used to specify this type
+ *   - Xen performs non-cooperative live migration and stores live
+ *     update state in memory, passing it to the new Xen.
  */
 
-#define KEXEC_TYPE_DEFAULT 0
-#define KEXEC_TYPE_CRASH   1
+#define KEXEC_TYPE_DEFAULT      0
+#define KEXEC_TYPE_CRASH        1
+#define KEXEC_TYPE_LIVEUPDATE   2
 
 
 /* The kexec implementation for Xen allows the user to load two
@@ -150,6 +155,8 @@ typedef struct xen_kexec_load_v1 {
 #define KEXEC_RANGE_MA_EFI_MEMMAP 5 /* machine address and size of
                                      * of the EFI Memory Map */
 #define KEXEC_RANGE_MA_VMCOREINFO 6 /* machine address and size of vmcoreinfo */
+/* machine address and size of the Live Update area below Xen */
+#define KEXEC_RANGE_MA_LIVEUPDATE 7
 
 /*
  * Find the address and size of certain memory areas
-- 
2.17.1