Re: [Qemu-devel] [PATCH] target-arm: handle address translations that start at level 3

[Peter Maydell]

On 13 November 2014 14:56, Peter Maydell <address@hidden> wrote:
> The ARMv8 address translation system defines that a page table walk
> starts at a level which depends on the translation granule size
> and the number of bits of virtual address that need to be resolved.
> Where the translation granule is 64KB and the guest sets the
> TCR.TxSZ field to between 35 and 39, it's actually possible to
> start at level 3 (the final level). QEMU's implementation failed
> to handle this case, and so we would set level to 2 and behave
> incorrectly (including invoking the C undefined behaviour of
> shifting left by a negative number). Correct the code that
> determines the starting level to deal with the start-at-3 case,
> by replacing the if-else ladder with an expression derived from
> the ARM ARM pseudocode version.
>
> This error was detected by the Coverity scan, which spotted
> the potential shift by a negative number.
>
> Signed-off-by: Peter Maydell <address@hidden>

Since this would be the sole patch in a target-arm pullreq
for 2.2rc2, I'm just going to apply it directly to master...

-- PMM