From: David Hildenbrand <david@redhat.com>
Date: Wed, 6 Sep 2023 12:04:57 +0000 (+0200)
Subject: softmmu/physmem: Bail out early in ram_block_discard_range() with readonly files
X-Git-Tag: v8.2.0-rc0~120^2~7
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b2cccb52bd9bef2948a150d204b20119b6c3ad58;p=thirdparty%2Fqemu.git

softmmu/physmem: Bail out early in ram_block_discard_range() with readonly files

fallocate() will fail, let's print a nicer error message.

Message-ID: <20230906120503.359863-6-david@redhat.com>
Suggested-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---

diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 88482bd32a0..c520c2ac554 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -3481,6 +3481,16 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length)
              * so a userfault will trigger.
              */
 #ifdef CONFIG_FALLOCATE_PUNCH_HOLE
+            /*
+             * fallocate() will fail with readonly files. Let's print a
+             * proper error message.
+             */
+            if (rb->flags & RAM_READONLY_FD) {
+                error_report("ram_block_discard_range: Discarding RAM"
+                             " with readonly files is not supported");
+                goto err;
+
+            }
             /*
              * We'll discard data from the actual file, even though we only
              * have a MAP_PRIVATE mapping, possibly messing with other