Hi
I ran into an mmap problem linux-user emulating CRIS (32bit) on x86_64 hosts.
Guest asks for a non fixed mmap, QEMU tries the mmap but the kernel returns a
high 64bit address. QEMU notices that it wont fit in the guests 32bit ptr size
and retries with a low address but doesn't set the MAP_FIXED flag.
Was something like the following patch the intended behaviour or did I
missunderstand something? (it fixes my problem at least...)
Cheers
commit 96fd8e3fdedb697ba249f32245751a28979c3fab
Author: Edgar E. Iglesias <edgar.igles...@gmail.com>
Date: Fri May 21 15:22:11 2010 +0200
linux-user: Set MAP_FIXED for mmap address fixups.
Signed-off-by: Edgar E. Iglesias <ed...@axis.com>
diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 6a1d933..5308fe1 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -304,7 +304,11 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size)
* - shmat() with SHM_REMAP flag
*/
ptr = mmap(g2h(addr), size, PROT_NONE,
- MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
+ /* When the kernel returns addresses that the guest
+ cannot use we might need to fallback to fixed
+ allocations. */
+ (addr ? MAP_FIXED : 0)
+ | MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
/* ENOMEM, if host address space has no memory */
if (ptr == MAP_FAILED) {
