Re: [Qemu-devel] [PATCH] target-arm: fix TTBCR write masking

[Peter Maydell]

On 10 December 2013 06:41, Sergey Fedorov <address@hidden> wrote:
> Current implementation is not accurate according to ARMv7-AR reference
> manual. See "B4.1.153 TTBCR, Translation Table Base Control Register,
> VMSA | TTBCR format when using the Long-descriptor translation table
> format". When LPAE feature is supported, EAE, bit[31] selects
> translation descriptor format and, therefore, TTBCR format.
>
> Signed-off-by: Sergey Fedorov <address@hidden>

Yeah, when I wrote that I was relying on the fact that all the
valid bits in a short-format descriptor are also valid in the
long-format mask, so correct guest software won't care (the
other bits are UNK/SBZP). However the implementation side
of UNK/SBZP requires us to treat the bits as RAZ/WI, so this
patch is correct.

Reviewed-by: Peter Maydell <address@hidden>

thanks
-- PMM