linux-user: Fix shmat emulation by honoring host SHMLBA
For those hosts with SHMLBA > getpagesize, we don't automatically
select a guest address that is compatible with the host. We can
achieve this by boosting the alignment of guest_base and by adding
an extra alignment argument to mmap_find_vma.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190519201953.20161-13-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index e5545cb..51cc049 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -3912,7 +3912,8 @@
else {
abi_ulong mmap_start;
- mmap_start = mmap_find_vma(0, shm_info.shm_segsz);
+ /* In order to use the host shmat, we need to honor host SHMLBA. */
+ mmap_start = mmap_find_vma(0, shm_info.shm_segsz, MAX(SHMLBA, shmlba));
if (mmap_start == -1) {
errno = ENOMEM;