Re: [Qemu-devel] [Qemu-arm] [PATCH] arm: check regime, not current state, for ATS write PAR format

[Alex Bennée]

Peter Maydell <address@hidden> writes:

> In do_ats_write(), rather than using extended_addresses_enabled() to
> decide whether the value we get back from get_phys_addr() is a 64-bit
> format PAR or a 32-bit one, use arm_s1_regime_using_lpae_format().
>
> This is not really the correct answer, because the PAR format
> depends on the AT instruction being used, not just on the
> translation regime. However getting this correct requires a
> significant refactoring, so that get_phys_addr() returns raw
> information about the fault which the caller can then assemble
> into a suitable FSR/PAR/syndrome for its purposes, rather than
> get_phys_addr() returning a pre-formatted FSR.
>
> However this change at least improves the situation by making
> the PAR work correctly for address translation operations done
> at AArch64 EL2 on the EL2 translation regime. In particular,
> this is necessary for Xen to be able to run in our emulation,
> so this seems like a safer interim fix given that we are in freeze.
>
> Signed-off-by: Peter Maydell <address@hidden>

As far as it goes it seems reasonable:

Reviewed-by: Alex Bennée <address@hidden>

> ---
> I guess I should have a go at the "correct answer" I sketch
> above, but no promises about when I'll get time for that :-(
>
>  target/arm/helper.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index 96113fe..37af750 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -2162,7 +2162,7 @@ static uint64_t do_ats_write(CPUARMState *env, uint64_t 
> value,
>
>      ret = get_phys_addr(env, value, access_type, mmu_idx,
>                          &phys_addr, &attrs, &prot, &page_size, &fsr, &fi);
> -    if (extended_addresses_enabled(env)) {
> +    if (arm_s1_regime_using_lpae_format(env, mmu_idx)) {
>          /* fsr is a DFSR/IFSR value for the long descriptor
>           * translation table format, but with WnR always clear.
>           * Convert it to a 64-bit PAR.


--
Alex Bennée