diff mbox series

[RFC,v3,05/22] Add KEXEC_TYPE_LIVE_UPDATE

Message ID 20200130161330.2324143-5-dwmw2@infradead.org (mailing list archive)
State New, archived
Headers show
Series Live update: boot memory management, data stream handling, record format | expand

Commit Message

David Woodhouse Jan. 30, 2020, 4:13 p.m. UTC 
From: David Woodhouse <dwmw@amazon.co.uk>

This is identical to the default case... for now.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 xen/common/kexec.c         | 18 ++++++++++++++++++
 xen/include/public/kexec.h | 12 ++++++++----
 2 files changed, 26 insertions(+), 4 deletions(-)
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Patch

diff --git a/xen/common/kexec.c b/xen/common/kexec.c
index a262cc5a18..a78aa4f5b0 100644
--- a/xen/common/kexec.c
+++ b/xen/common/kexec.c
@@ -404,6 +404,19 @@  static long kexec_reboot(void *_image)
     return 0;
 }
 
+static long kexec_live_update(void *_image)
+{
+    struct kexec_image *image = _image;
+
+    kexecing = TRUE;
+
+    kexec_common_shutdown();
+    machine_reboot_kexec(image);
+
+    BUG();
+    return 0;
+}
+
 static void do_crashdump_trigger(unsigned char key)
 {
     printk("'%c' pressed -> triggering crashdump\n", key);
@@ -736,6 +749,7 @@  static int kexec_load_get_bits(int type, int *base, int *bit)
     switch ( type )
     {
     case KEXEC_TYPE_DEFAULT:
+    case KEXEC_TYPE_LIVE_UPDATE:
         *base = KEXEC_IMAGE_DEFAULT_BASE;
         *bit = KEXEC_FLAG_DEFAULT_POS;
         break;
@@ -837,6 +851,10 @@  static int kexec_exec(XEN_GUEST_HANDLE_PARAM(void) uarg)
         image = kexec_image[base + pos];
         ret = continue_hypercall_on_cpu(0, kexec_reboot, image);
         break;
+    case KEXEC_TYPE_LIVE_UPDATE:
+        image = kexec_image[base + pos];
+        ret = continue_hypercall_on_cpu(0, kexec_live_update, image);
+        break;
     case KEXEC_TYPE_CRASH:
         kexec_crash(); /* Does not return */
         break;
diff --git a/xen/include/public/kexec.h b/xen/include/public/kexec.h
index 298381af8d..f5230286d3 100644
--- a/xen/include/public/kexec.h
+++ b/xen/include/public/kexec.h
@@ -71,18 +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 guest-transparent 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_LIVE_UPDATE      2
 
 /* The kexec implementation for Xen allows the user to load two
  * types of kernels, KEXEC_TYPE_DEFAULT and KEXEC_TYPE_CRASH.