The primary issue is that of overflow, where "end" for the last
page of the 32-bit address space overflows to 0. The fix is to
use "last" instead, which can always be represented.
This requires that we adjust reserved_va as well, because of
-/*
- * There are a number of places where we assign reserved_va to a variable
- * of type abi_ulong and expect it to fit. Avoid the last page.
- */
-# define MAX_RESERVED_VA (0xfffffffful & TARGET_PAGE_MASK)
and the related
- /*
- * reserved_va must be aligned with the host page size
- * as it is used with mmap()
- */
- reserved_va = local_max_va & qemu_host_page_mask;
whereby we avoided the final (host | guest) page of the address space
because of said overflow. With the change in representation, we can
always use UINT32_MAX as the end of the 32-bit address space.
This was observable on ppc64le (or any other 64k page host) not being
able to load any arm32 binary, because the COMMPAGE goes at 0xffff0000,
which violated that last host page problem above.
The issue is resolved in patch 4, but the rest clean up other interfaces
with the same issue. I'm not touching any interfaces that use start+len
instead of start+end.