[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] Re: sparc64's get_physical_address_code should not fault on
From: |
Blue Swirl |
Subject: |
[Qemu-devel] Re: sparc64's get_physical_address_code should not fault on TTE's with V=0 |
Date: |
Mon, 12 Jan 2009 23:10:56 +0200 |
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.