We want to actually resize ram blocks (make everything between
used_length and max_length inaccessible) - however, not all ram block
notifiers will support that.

So introduce a way to detect if any registered notifier does not support
it and add a way to notify all notifiers that support it.

Using ram_block_notifiers_support_resize(), we can keep the existing
handling for these special cases until they implement support (e.g.,
SEV, HAX) to resize.

Cc: Richard Henderson <rth@twiddle.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 hw/core/numa.c         | 21 +++++++++++++++++++++
 include/exec/ramlist.h |  4 ++++
 util/trace-events      |  1 +
 3 files changed, 26 insertions(+)

diff --git a/hw/core/numa.c b/hw/core/numa.c
index fed4046680..5ccfcbcd41 100644
--- a/hw/core/numa.c
+++ b/hw/core/numa.c
@@ -940,3 +940,24 @@ void ram_block_notify_remove(void *host, size_t size)
         notifier->ram_block_removed(notifier, host, size);
     }
 }
+
+void ram_block_notify_resized(void *host, size_t oldsize, size_t newsize)
+{
+    RAMBlockNotifier *notifier;
+
+    QLIST_FOREACH(notifier, &ram_list.ramblock_notifiers, next) {
+        notifier->ram_block_resized(notifier, host, oldsize, newsize);
+    }
+}
+
+bool ram_block_notifiers_support_resize(void)
+{
+    RAMBlockNotifier *notifier;
+
+    QLIST_FOREACH(notifier, &ram_list.ramblock_notifiers, next) {
+        if (!notifier->ram_block_resized) {
+            return false;
+        }
+    }
+    return true;
+}
diff --git a/include/exec/ramlist.h b/include/exec/ramlist.h
index bc4faa1b00..33a380cbee 100644
--- a/include/exec/ramlist.h
+++ b/include/exec/ramlist.h
@@ -67,6 +67,8 @@ void qemu_mutex_unlock_ramlist(void);
 struct RAMBlockNotifier {
     void (*ram_block_added)(RAMBlockNotifier *n, void *host, size_t size);
     void (*ram_block_removed)(RAMBlockNotifier *n, void *host, size_t size);
+    void (*ram_block_resized)(RAMBlockNotifier *n, void *host, size_t oldsize,
+                              size_t newsize);
     QLIST_ENTRY(RAMBlockNotifier) next;
 };
 
@@ -74,6 +76,8 @@ void ram_block_notifier_add(RAMBlockNotifier *n);
 void ram_block_notifier_remove(RAMBlockNotifier *n);
 void ram_block_notify_add(void *host, size_t size);
 void ram_block_notify_remove(void *host, size_t size);
+void ram_block_notify_resized(void *host, size_t oldsize, size_t newsize);
+bool ram_block_notifiers_support_resize(void);
 
 void ram_block_dump(Monitor *mon);
 
diff --git a/util/trace-events b/util/trace-events
index 83b6639018..226f406c46 100644
--- a/util/trace-events
+++ b/util/trace-events
@@ -76,6 +76,7 @@ qemu_mutex_unlock(void *mutex, const char *file, const int line) "released mutex
 qemu_vfio_dma_reset_temporary(void *s) "s %p"
 qemu_vfio_ram_block_added(void *s, void *p, size_t size) "s %p host %p size 0x%zx"
 qemu_vfio_ram_block_removed(void *s, void *p, size_t size) "s %p host %p size 0x%zx"
+qemu_vfio_ram_block_resized(void *s, void *p, size_t oldsize, size_t newsizze) "s %p host %p oldsize 0x%zx newsize 0x%zx"
 qemu_vfio_find_mapping(void *s, void *p) "s %p host %p"
 qemu_vfio_new_mapping(void *s, void *host, size_t size, int index, uint64_t iova) "s %p host %p size %zu index %d iova 0x%"PRIx64
 qemu_vfio_do_mapping(void *s, void *host, size_t size, uint64_t iova) "s %p host %p size %zu iova 0x%"PRIx64
-- 
2.24.1