Re: [PATCH v2 02/12] target/arm: Enforce that FPDSCR.LTPSIZE is 4 on inbound migration

[Richard Henderson]

On 9/13/21 2:54 AM, Peter Maydell wrote:
> Architecturally, for an M-profile CPU with the LOB feature the
> LTPSIZE field in FPDSCR is always constant 4.  QEMU's implementation
> enforces this everywhere, except that we don't check that it is true
> in incoming migration data.
>
> We're going to add come in gen_update_fp_context() which relies on

"code"

> the "always 4" property.  Since this is TCG-only, we don't actually
> need to be robust to bogus incoming migration data, and the effect of
> it being wrong would be wrong code generation rather than a QEMU
> crash; but if it did ever happen somehow it would be very difficult
> to track down the cause.  Add a check so that we fail the inbound
> migration if the FPDSCR.LTPSIZE value is incorrect.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~