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From: Peter Maydell <peter.maydell@linaro.org>
Date: Sun, 17 Nov 2013 16:26:57 +0000
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Subject: Re: [Qemu-devel] [PATCH] fix initrd load failed
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To: ChenQun <chenq009@gmail.com>
Cc: QEMU Developers <qemu-devel@nongnu.org>, "kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>

On 17 November 2013 16:10, ChenQun <chenq009@gmail.com> wrote:
> Here's a bug, some examples are as follows:
> 1.Assuming Guest's filesystem size 6M.
> 2.For vexpress_a15, the loader_start = 2048M.
> If we set guest ram_size range from  2048M+128M to 2048M+128M+6M,
>   then the initrd load failed.
> 3.For mach-virt, the loader_start = 128M.
> If we set guest ram_size range from 256M to 256M+6M, then it is
> failed too.
>
> So,it is a bug for load initrd max mem calculation.
> It should be (ram_size + loader_start - initrd_start).

Yes, this is definitely a bug. The set of addresses/sizes we
pass to the loader is a bit of a mess, though -- we kind of
implicitly assume that "loader_start" means "bottom of RAM",
and that all the ram is in one chunk. However for example
realview-pbx-a9 sets loader_start to 0 when the size of that
bit of RAM may be less than the total ram_size. The device
tree editing code also assumes a single contiguous block
of RAM...

thanks
-- PMM