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[PATCH v2 5/9] accel/tcg: Pass last not end to page_reset_target_data


From: Richard Henderson
Subject: [PATCH v2 5/9] accel/tcg: Pass last not end to page_reset_target_data
Date: Fri, 17 Mar 2023 08:54:51 -0700

Pass the address of the last byte to be changed, rather than
the first address past the last byte.  This avoids overflow
when the last page of the address space is involved.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/exec/cpu-all.h |  2 +-
 accel/tcg/user-exec.c  | 11 +++++------
 linux-user/mmap.c      |  2 +-
 3 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index db38418d93..981c295de9 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -286,7 +286,7 @@ int walk_memory_regions(void *, walk_memory_regions_fn);
 
 int page_get_flags(target_ulong address);
 void page_set_flags(target_ulong start, target_ulong last, int flags);
-void page_reset_target_data(target_ulong start, target_ulong end);
+void page_reset_target_data(target_ulong start, target_ulong last);
 int page_check_range(target_ulong start, target_ulong len, int flags);
 
 /**
diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
index 035f8096b2..20b6fc2f6e 100644
--- a/accel/tcg/user-exec.c
+++ b/accel/tcg/user-exec.c
@@ -508,7 +508,7 @@ void page_set_flags(target_ulong start, target_ulong last, 
int flags)
     }
 
     if (!flags || reset) {
-        page_reset_target_data(start, last + 1);
+        page_reset_target_data(start, last);
         inval_tb |= pageflags_unset(start, last);
     }
     if (flags) {
@@ -814,15 +814,14 @@ typedef struct TargetPageDataNode {
 
 static IntervalTreeRoot targetdata_root;
 
-void page_reset_target_data(target_ulong start, target_ulong end)
+void page_reset_target_data(target_ulong start, target_ulong last)
 {
     IntervalTreeNode *n, *next;
-    target_ulong last;
 
     assert_memory_lock();
 
-    start = start & TARGET_PAGE_MASK;
-    last = TARGET_PAGE_ALIGN(end) - 1;
+    start &= TARGET_PAGE_MASK;
+    last |= ~TARGET_PAGE_MASK;
 
     for (n = interval_tree_iter_first(&targetdata_root, start, last),
          next = n ? interval_tree_iter_next(n, start, last) : NULL;
@@ -885,7 +884,7 @@ void *page_get_target_data(target_ulong address)
     return t->data[(page - region) >> TARGET_PAGE_BITS];
 }
 #else
-void page_reset_target_data(target_ulong start, target_ulong end) { }
+void page_reset_target_data(target_ulong start, target_ulong last) { }
 #endif /* TARGET_PAGE_DATA_SIZE */
 
 /* The softmmu versions of these helpers are in cputlb.c.  */
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 9c70f51d97..0aa8ae7356 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -946,7 +946,7 @@ abi_long target_madvise(abi_ulong start, abi_ulong len_in, 
int advice)
         if (can_passthrough_madvise(start, end)) {
             ret = get_errno(madvise(g2h_untagged(start), len, advice));
             if ((advice == MADV_DONTNEED) && (ret == 0)) {
-                page_reset_target_data(start, start + len);
+                page_reset_target_data(start, start + len - 1);
             }
         }
     }
-- 
2.34.1




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