Re: [Xen-ia64-devel] [PATCH] Strange problem with virtual aliases

[Isaku Yamahata <yamahata@xxxxxxxxxxxxx>]

Alex, could you mind to take care of this patch?
It seems that there is no objection and I believe that it is necessary.
I added my signed-off-by because Matthew didn't send his signed-off-by.
If he send his signed-off-by, please replace it with his own.

On Thu, Nov 30, 2006 at 03:17:57PM +1100, Matthew Chapman wrote:
> I found the problem...
> 
> The real VHPT insertion is done based on the machine PTE returned from
> translate_domain_pte, which does the appropriate offset calculations.
> 
> However, the insertion into the one-entry TLB uses the original PTE, but
> the page size has been reset to PAGE_SIZE [1].  Thus the entry in the
> one-entry TLB incorrectly maps the PAGE_SIZE sub-page which was faulted
> on to the PAGE_SIZE sub-page at the bottom of the superpage.
> 
> I think it makes most sense to simply use the original itir when
> inserting into the single-entry TLB, as per attached patch.  I've moved
> the vcpu_set_tr_entry calls up a level into vcpu_itc_d and vcpu_itc_i;
> the third caller previously used the 4 flag to specify "don't do that".
> 
> Matt
> 
> [1] In fact, this is enforced twice, once in translate_domain_pte and
> again in vcpu_itc_no_srlz.
> 

> diff -r 0114b372dfae xen/arch/ia64/xen/faults.c
> --- a/xen/arch/ia64/xen/faults.c      Wed Nov 22 10:13:31 2006 -0700
> +++ b/xen/arch/ia64/xen/faults.c      Thu Nov 30 14:51:33 2006 +1100
> @@ -215,7 +215,7 @@ void ia64_do_page_fault(unsigned long ad
>               unsigned long m_pteval;
>               m_pteval = translate_domain_pte(pteval, address, itir,
>                                               &logps, &entry);
> -             vcpu_itc_no_srlz(current, (is_data ? 2 : 1) | 4,
> +             vcpu_itc_no_srlz(current, is_data ? 2 : 1,
>                                address, m_pteval, pteval, logps, &entry);
>               if ((fault == IA64_USE_TLB && !current->arch.dtlb.pte.p) ||
>                   p2m_entry_retry(&entry)) {
> diff -r 0114b372dfae xen/arch/ia64/xen/vcpu.c
> --- a/xen/arch/ia64/xen/vcpu.c        Wed Nov 22 10:13:31 2006 -0700
> +++ b/xen/arch/ia64/xen/vcpu.c        Thu Nov 30 14:54:11 2006 +1100
> @@ -2181,14 +2181,6 @@ vcpu_itc_no_srlz(VCPU * vcpu, u64 IorD, 
>       else
>               vhpt_insert(vaddr, pte, PAGE_SHIFT << 2);
>  #endif
> -     if (IorD & 0x4)         /* don't place in 1-entry TLB */
> -             return;
> -     if (IorD & 0x1) {
> -             vcpu_set_tr_entry(&PSCBX(vcpu, itlb), mp_pte, ps << 2, vaddr);
> -     }
> -     if (IorD & 0x2) {
> -             vcpu_set_tr_entry(&PSCBX(vcpu, dtlb), mp_pte, ps << 2, vaddr);
> -     }
>  }
>  
>  IA64FAULT vcpu_itc_d(VCPU * vcpu, u64 pte, u64 itir, u64 ifa)
> @@ -2215,6 +2207,7 @@ IA64FAULT vcpu_itc_d(VCPU * vcpu, u64 pt
>               vcpu_flush_tlb_vhpt_range(ifa, logps);
>               goto again;
>       }
> +     vcpu_set_tr_entry(&PSCBX(vcpu, dtlb), pte, itir, ifa);
>       return IA64_NO_FAULT;
>  }
>  
> @@ -2241,6 +2234,7 @@ IA64FAULT vcpu_itc_i(VCPU * vcpu, u64 pt
>               vcpu_flush_tlb_vhpt_range(ifa, logps);
>               goto again;
>       }
> +     vcpu_set_tr_entry(&PSCBX(vcpu, itlb), pte, itir, ifa);
>       return IA64_NO_FAULT;
>  }
>  

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-- 
yamahata

Attachment: 13361_1f83fb7a050c_tlb_insert_cache_fix.patch
Description: Text Data

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