Re: [PATCH] target/arm: Widen cnthctl_el2 to uint64_t

[Peter Maydell]

On Sun, 15 Jan 2023 at 17:16, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> This is a 64-bit register on AArch64, even if the high 44 bits
> are RES0.  Because this is defined as ARM_CP_STATE_BOTH, we are
> asserting that the cpreg field is 64-bits.
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1400
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>
> During my perigrinations of reorganizing cpregs, I've been thinking
> of ways to detect these sorts of errors -- preferably at build time,
> but failing that at startup.  I think all raw usage of offsetof has
> got to be replaced with something like
>
> #define cpreg_fieldoffset(field) \
>     .fieldoffset = offsetof(CPUARMState, field), \
>     .fieldsize = sizeof(((CPUARMState *)0)->field),

The other cpreg sanity check I've vaguely wondered about in
the past is whether we can somehow check that all the fields
that we expose to the guest as a register are migrated. This
definitely isn't true currently because for a 32-bit CPU with
TrustZone we messed up migration of the Secure banked state.
Incorrect use of alias flags could also result in that kind
of bug. I guess we'd need to have some way to tell the check
about fields that really are manually migrated, though.

Anyway, for this patch, applied to target-arm.next.

thanks
-- PMM