Re: [Qemu-devel] [PATCH v2 0/4] hw/arm/boot: handle large Images more gracefully

[Peter Maydell <peter.maydell@linaro.org>]

Ping for code review, please?

thanks
-- PMM

On Thu, 16 May 2019 at 15:47, Peter Maydell <peter.maydell@linaro.org> wrote:
>
>
> This patchset attempts to fix https://bugs.launchpad.net/qemu/+bug/1823998
> which reports that we don't handle kernels larger than 128MB
> correctly, because we allow the initrd to be placed over the
> tail end of the kernel. AArch64 kernel Image files (since v3.17)
> report the total size they require (including any BSS area that
> isn't in the Image itself), so we can use that to be sure we
> place the initrd sufficiently far into the RAM.
>
> Patches 1 and 2 are new since v1; patches 3 and 4 are the old
> patches 1 and 2 (and are basically unchanged since v1).
>
> Patches 1 and 2 in this series are new. Patch 1 fixes bugs
> in the existing code where we were assuming that we could
> treat info->ram_size as the address of the end of RAM, which
> isn't true if the RAM doesn't start at address 0. (This
> generally went unnoticed thanks to the magic of unsigned integer
> underflow turning end-start calculations into very large max_size
> values for load_ramdisk_as() and friends.)
> Patch 2 adds some explicit checks that we don't try to put things
> entirely off the end of RAM (which avoids those accidental
> underflows).
> Patch 3 in this series adjusts our "where do we put the initrd"
> heuristic so that it always places it at least after whatever
> our best guess at the kernel size is. (This might still not
> be right for images like self-decompressing 32-bit kernels, where
> there's no way to know how big the kernel will be after
> decompression.)
> Patch 4 makes load_aarch64_image() return the
> kernel size as indicated in the Image file header, so that for
> the specific case of AArch64 Image files we will definitely not
> put the initrd on top of them.
>
> thanks
> -- PMM
>
> Peter Maydell (4):
>   hw/arm/boot: Don't assume RAM starts at address zero
>   hw/arm/boot: Diagnose layouts that put initrd or DTB off the end of
>     RAM
>   hw/arm/boot: Avoid placing the initrd on top of the kernel
>   hw/arm/boot: Honour image size field in AArch64 Image format kernels
>
>  hw/arm/boot.c | 83 ++++++++++++++++++++++++++++++++++++++-------------
>  1 file changed, 62 insertions(+), 21 deletions(-)
>
> --
> 2.20.1
>