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Re: [Xen-devel] [PATCH] [Xen] Check FADT's signature




> Okay, please try tip of staging tree (c/s 15773).

This solves the problem with mapping ACPI memory and the timer address is read correctly. Thanks!

  Stefan

>
>  -- Keir
>
> On 24/8/07 07:19, "Stefan Berger" <stefanb@xxxxxxxxxx> wrote:

>
> xen-devel-bounces@xxxxxxxxxxxxxxxxxxx wrote on 08/10/2007 09:15:57 PM:
>
> > A good debugging approach will be to write a function that walks the
> > pagetables for that virtual address and prints the PTE that maps it.
> > Scatter calls to this function between acpi_boot_table_init() and
> > acpi_boot_init() and hence narrow down exactly where the PTE is
> > getting zapped.
>
> What is happening is that the pl1e pointer used for mapping the ACPI
> table entry changes between the calls before paging_init() and
> after. The l1_pgentry_t that is used before paging_init() correctly
> shows that the page is present whereas the one used after indicates
> that the page is not present. Then when the ACPI table is mapped
> after paging_init() the tlb is not flushed and wrong information is read.
>
>   Stefan
>
> >
> >  -- Keir
> >
> > On 10/8/07 19:21, "Keir Fraser" <keir@xxxxxxxxxxxxx> wrote:
>
> > On 10/8/07 18:00, "Stefan Berger" <stefanb@xxxxxxxxxx> wrote:
>
> > (XEN) map_pages_to_xen : 3533                                    
> > (that's the line number)
> > (XEN) 0xfff9b000 was NOT present.
> >
> > Something between (*) and here seems to trash this presence flag.
> > paging_init() and many others lie in between the upper call and this
> > one here. Could be a side effect of this? Maybe that tlb flush at
> > the right place in one of these functions would solve the problem?
> >
> > Yes, this now looks likely and that’s rather scary. We’ll go after
> > this next week.
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel
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