[PULL,07/15] accel/tcg: Pass last not end to page_collection_lock

Commit Message

Richard Henderson March 28, 2023, 10:57 p.m. UTC

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.

Fixes a bug in the loop comparision where "<= end" would lock
one more page than required.

Reviewed-by: Philippe Mathieu-Daudé <[e-mail]>
Signed-off-by: Richard Henderson <[e-mail]>
---
 accel/tcg/tb-maint.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

Patch

diff --git a/accel/tcg/tb-maint.c b/accel/tcg/tb-maint.c
index 04d2751bb6..57da2feb2f 100644
--- a/accel/tcg/tb-maint.c
+++ b/accel/tcg/tb-maint.c
@@ -511,20 +511,20 @@  static gint tb_page_addr_cmp(gconstpointer ap, gconstpointer bp, gpointer udata)
 }
 
 /*
- * Lock a range of pages ([@start,@end[) as well as the pages of all
+ * Lock a range of pages ([@start,@last]) as well as the pages of all
  * intersecting TBs.
  * Locking order: acquire locks in ascending order of page index.
  */
 static struct page_collection *page_collection_lock(tb_page_addr_t start,
-                                                    tb_page_addr_t end)
+                                                    tb_page_addr_t last)
 {
     struct page_collection *set = g_malloc(sizeof(*set));
     tb_page_addr_t index;
     PageDesc *pd;
 
     start >>= TARGET_PAGE_BITS;
-    end   >>= TARGET_PAGE_BITS;
-    g_assert(start <= end);
+    last >>= TARGET_PAGE_BITS;
+    g_assert(start <= last);
 
     set->tree = q_tree_new_full(tb_page_addr_cmp, NULL, NULL,
                                 page_entry_destroy);
@@ -534,7 +534,7 @@  static struct page_collection *page_collection_lock(tb_page_addr_t start,
  retry:
     q_tree_foreach(set->tree, page_entry_lock, NULL);
 
-    for (index = start; index <= end; index++) {
+    for (index = start; index <= last; index++) {
         TranslationBlock *tb;
         PageForEachNext n;
 
@@ -1154,7 +1154,7 @@  tb_invalidate_phys_page_range__locked(struct page_collection *pages,
 void tb_invalidate_phys_page(tb_page_addr_t addr)
 {
     struct page_collection *pages;
-    tb_page_addr_t start, end;
+    tb_page_addr_t start, last;
     PageDesc *p;
 
     p = page_find(addr >> TARGET_PAGE_BITS);
@@ -1163,9 +1163,9 @@  void tb_invalidate_phys_page(tb_page_addr_t addr)
     }
 
     start = addr & TARGET_PAGE_MASK;
-    end = start + TARGET_PAGE_SIZE;
-    pages = page_collection_lock(start, end);
-    tb_invalidate_phys_page_range__locked(pages, p, start, end, 0);
+    last = addr | ~TARGET_PAGE_MASK;
+    pages = page_collection_lock(start, last);
+    tb_invalidate_phys_page_range__locked(pages, p, start, last + 1, 0);
     page_collection_unlock(pages);
 }
 
@@ -1181,7 +1181,7 @@  void tb_invalidate_phys_range(tb_page_addr_t start, tb_page_addr_t end)
     struct page_collection *pages;
     tb_page_addr_t next;
 
-    pages = page_collection_lock(start, end);
+    pages = page_collection_lock(start, end - 1);
     for (next = (start & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE;
          start < end;
          start = next, next += TARGET_PAGE_SIZE) {
@@ -1226,7 +1226,7 @@  void tb_invalidate_phys_range_fast(ram_addr_t ram_addr,
 {
     struct page_collection *pages;
 
-    pages = page_collection_lock(ram_addr, ram_addr + size);
+    pages = page_collection_lock(ram_addr, ram_addr + size - 1);
     tb_invalidate_phys_page_fast__locked(pages, ram_addr, size, retaddr);
     page_collection_unlock(pages);
 }