From: "Dr. David Alan Gilbert" <[email protected]>
Signed-off-by: Dr. David Alan Gilbert <[email protected]>
---
include/migration/postcopy-ram.h | 5 +++++
postcopy-ram.c | 36 +++++++++++++++++++++++++++++++++++-
2 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/include/migration/postcopy-ram.h b/include/migration/postcopy-ram.h
index ca2045b..fc23558 100644
--- a/include/migration/postcopy-ram.h
+++ b/include/migration/postcopy-ram.h
@@ -28,6 +28,11 @@ int postcopy_send_discard_bitmap(MigrationState *ms);
int postcopy_ram_discard_range(MigrationIncomingState *mis, uint8_t *start,
uint8_t *end);
+/*
+ * Make all of RAM sensitive to accesses to areas that haven't yet been written
+ * and wire up anything necessary to deal with it.
+ */
+int postcopy_ram_enable_notify(MigrationIncomingState *mis);
/*
* Initialise postcopy-ram, setting the RAM to a state where we can go into
diff --git a/postcopy-ram.c b/postcopy-ram.c
index b1fbabd..5b52542 100644
--- a/postcopy-ram.c
+++ b/postcopy-ram.c
@@ -352,9 +352,38 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState
*mis)
return 0;
}
+/*
+ * Mark the given area of RAM as requiring notification to unwritten areas
+ * Used as a callback on qemu_ram_foreach_block.
+ * host_addr: Base of area to mark
+ * offset: Offset in the whole ram arena
+ * length: Length of the section
+ * opaque: Unused
+ * Returns 0 on success
+ */
+static int postcopy_ram_sensitise_area(const char *block_name, void *host_addr,
+ ram_addr_t offset, ram_addr_t length,
+ void *opaque)
+{
+ if (madvise(host_addr, length, MADV_USERFAULT)) {
+ perror("postcopy_ram_sensitise_area");
+ return -1;
+ }
+ return 0;
+}
+
+int postcopy_ram_enable_notify(MigrationIncomingState *mis)
+{
+ /* Mark so that we get notified of accesses to unwritten areas */
+ if (qemu_ram_foreach_block(postcopy_ram_sensitise_area, NULL)) {
+ return -1;
+ }
+
+ return 0;
+}
+
#else
/* No target OS support, stubs just fail */
-
int postcopy_ram_hosttest(void)
{
error_report("postcopy_ram_hosttest: No OS support");
@@ -387,6 +416,11 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState
*mis)
return -1;
}
+int postcopy_ram_enable_notify(MigrationIncomingState *mis)
+{
+ fprintf(stderr, "postcopy_ram_enable_notify: No OS support\n");
+ return -1;
+}
#endif
/* ------------------------------------------------------------------------- */
--
1.9.3
