[PATCH 1/9] linux-user: Diagnose incorrect -R size

[Richard Henderson]

Zero is the value for 'off', and should not be used with -R.
We have been enforcing host page alignment for the non-R
fallback of MAX_RESERVED_VA, but failing to enforce for -R.

Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
 linux-user/main.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/linux-user/main.c b/linux-user/main.c
index 4ff30ff980..f4dea25242 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -395,6 +395,16 @@ static void handle_arg_reserved_va(const char *arg)
         fprintf(stderr, "Unrecognised -R size suffix '%s'\n", p);
         exit(EXIT_FAILURE);
     }
+    if (reserved_va == 0) {
+        fprintf(stderr, "Invalid -R size value 0\n");
+        exit(EXIT_FAILURE);
+    }
+    /* Must be aligned with the host page size as it is used with mmap. */
+    if (reserved_va & qemu_host_page_mask) {
+        fprintf(stderr, "Invalid -R size value %lu: must be aligned mod %lu\n",
+               reserved_va, qemu_host_page_size);
+        exit(EXIT_FAILURE);
+    }
 }
 
 static void handle_arg_singlestep(const char *arg)
-- 
2.34.1