[Qemu-devel] Re: sparc64's get_physical_address_code should not fault on TTE's with V=0

[Blue Swirl]

On 1/12/09, Jakub Jermar <address@hidden> wrote:
> Hi,
>
>  when I make the following change to helper.c, get_physical_address_code:
>
>  -        // ctx match, vaddr match?
>  +        // ctx match, vaddr match, valid?
>          if (env->dmmuregs[1] == (env->itlb_tag[i] & 0x1fff) &&
>  -            (address & mask) == (env->itlb_tag[i] & ~0x1fffULL)) {
>  -            // valid, access ok?
>  -            if ((env->itlb_tte[i] & 0x8000000000000000ULL) == 0 ||
>  -                ((env->itlb_tte[i] & 0x4) && is_user)) {
>  +            (address & mask) == (env->itlb_tag[i] & ~0x1fffULL) &&
>  +            env->itlb_tte[i] & 0x8000000000000000ULL) {
>  +            // access ok?
>  +            if ((env->itlb_tte[i] & 0x4) && is_user) {
>
>  HelenOS gets a little bit further than without this change and seems
>  to panic more or less gracefully later.
>
>  In short, non-valid entries should be skipped by the loop in
>  get_physical_address_code instead of causing TFAULT, because
>  the ITLB can contain a valid entry for the same address. The
>  same is true for DTLB.
>
>  Can you confirm this?

Yes, this looks correct. I'll apply a fix.