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[Qemu-devel] Re: linux-user issues
From: |
Paul Brook |
Subject: |
[Qemu-devel] Re: linux-user issues |
Date: |
Sat, 13 Mar 2010 00:45:22 +0000 |
User-agent: |
KMail/1.12.4 (Linux/2.6.32-trunk-amd64; KDE/4.3.4; x86_64; ; ) |
> a) elfload.c:859
>
> #define TARGET_ELF_PAGESTART(_v) ((_v) & ~(unsigned
> long)(TARGET_ELF_EXEC_PAGESIZE-1))
>
> This means that for 64bit guest on a 32bit host the _v's value is
> silently reduced to 32bit, the cast should be abi_ulong.
>
> b) mmap.c:428
>
> real_start = start & qemu_host_page_mask;
>
> Same thing basically qemu_host_page_mask is unsigned long and so
> the upper bits are sliently cleared. Again qemu_host_page_mask
> should probably be abi_ulong.
>
> The above two make elf binary with one of the segments above 4G load
> and run on 32bit guest only to fail well into execution and without
> any indication that it shouldn't have been allowed to run in the first
> place.
I'd be amazed if these are the only two issues, and expect 64-bit guests on
32-bit hosts to be generally unsafe.
Paul