linux-user/hppa: Simplify init_guest_commpage

If reserved_va, then we have already reserved the entire
guest virtual address space; no need to remap page.
If !reserved_va, then use MAP_FIXED_NOREPLACE.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Helge Deller <deller@gmx.de>
Message-Id: <20240102015808.132373-6-richard.henderson@linaro.org>

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 0f135f6b6d1796f5da3521d6d15971cb3d374029..53b61aac77d9450b81a2209b51858277dfdaaedf 100644 (file)
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1970,16 +1970,20 @@ static inline void init_thread(struct target_pt_regs *regs,
 
 static bool init_guest_commpage(void)
 {
-    void *want = g2h_untagged(LO_COMMPAGE);
-    void *addr = mmap(want, qemu_host_page_size, PROT_NONE,
-                      MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0);
-
-    if (addr == MAP_FAILED) {
-        perror("Allocating guest commpage");
-        exit(EXIT_FAILURE);
-    }
-    if (addr != want) {
-        return false;
+    /* If reserved_va, then we have already mapped 0 page on the host. */
+    if (!reserved_va) {
+        void *want, *addr;
+
+        want = g2h_untagged(LO_COMMPAGE);
+        addr = mmap(want, TARGET_PAGE_SIZE, PROT_NONE,
+                    MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED_NOREPLACE, -1, 0);
+        if (addr == MAP_FAILED) {
+            perror("Allocating guest commpage");
+            exit(EXIT_FAILURE);
+        }
+        if (addr != want) {
+            return false;
+        }
     }
 
     /*