[PATCH v2 06/13] exec: Relax range check in ram_block_discard_range()

[David Hildenbrand]

We want to make use of ram_block_discard_range() in the RAM block resize
callback when growing a RAM block, *before* used_length is changed.
Let's relax the check. We always have a reserved mapping for the whole
max_length, so we cannot corrupt unrelated data.

Cc: Richard Henderson <r...@twiddle.net>
Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: Eduardo Habkost <ehabk...@redhat.com>
Cc: Peter Xu <pet...@redhat.com>
Signed-off-by: David Hildenbrand <da...@redhat.com>
---
 exec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/exec.c b/exec.c
index 8b015821d6..8737acedab 100644
--- a/exec.c
+++ b/exec.c
@@ -3915,7 +3915,7 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, 
size_t length)
         goto err;
     }
 
-    if ((start + length) <= rb->used_length) {
+    if ((start + length) <= rb->max_length) {
         bool need_madvise, need_fallocate;
         if (!QEMU_IS_ALIGNED(length, rb->page_size)) {
             error_report("ram_block_discard_range: Unaligned length: %zx",
@@ -3982,7 +3982,7 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, 
size_t length)
     } else {
         error_report("ram_block_discard_range: Overrun block '%s' (%" PRIu64
                      "/%zx/" RAM_ADDR_FMT")",
-                     rb->idstr, start, length, rb->used_length);
+                     rb->idstr, start, length, rb->max_length);
     }
 
 err:
-- 
2.24.1