Hi Jes,
I wrote the patch corresponding to discontig. You are wrong.
alloc_dir_page() must return a physical address because the page table
walker for frame_table runs under off-state of data-address-translation.
(i.e. psr.dt=0)
p*d_populate() functions never be called while handling TLB miss to
frame_table. The page table walker for frame_table is written in
assembler in xen/arch/ia64/xen/ivt.S. See the code between
'GLOBAL_ENTRY(frametable_miss)' and 'END(frametable_miss)'
You'd better have a look at the thread below:
http://lists.xensource.com/archives/html/xen-ia64-devel/2006-04/msg00014.html
Thanks,
Kouya
Jes Sorensen writes:
> Hi,
>
> I sent this patch to Alex last week, but it didn't make it onto the list
> because it's wrongly configured, so here we go again.
>
> I know that this patch is causing problems on ZX1, but I have looked at
> it over and over again and I feel pretty certain it is correct. In fact
> I cannot understand that Xen could boot on any ia64 platform prior to
> this at all.
>
> I would be very interested in hearing how this patch affects other
> platforms such as DIG and Fujitsu's machines (if they are not DIG :)
>
> Any input or comments on this is most welcome - if you think I am wrong
> about this patch, please tell me, I really want to understand why this
> worked in the past.
>
> Thanks,
> Jes
>
> alloc_dir_page() must return a virtual address so it can handle being
> passed to the p*d_populate() functions which do a __pa() on the address
> before sticking them into the page tables.
>
> To match this it is also necessary to correctly check the faulting
> address for being in the virtual frame table range, otherwise page
> faults for this space weren't being served at all.
>
> This could probably be done more efficiently, but for now I think it's
> better to keep the code explicit.
>
> Signed-off-by: Jes Sorensen <jes@xxxxxxx>
>
> diff -r 3e4fa8b5b245 xen/arch/ia64/xen/ivt.S
> --- a/xen/arch/ia64/xen/ivt.S Tue Sep 12 11:43:22 2006 -0600
> +++ b/xen/arch/ia64/xen/ivt.S Wed Sep 20 14:56:37 2006 +0200
> @@ -542,8 +542,16 @@ late_alt_dtlb_miss:
> ;;
> #ifdef CONFIG_VIRTUAL_FRAME_TABLE
> shr r22=r16,56 // Test for the address of virtual frame_table
> +#if 1
> + mov r23=VIRT_FRAME_TABLE_ADDR>>56
> + ;;
> + xor r23=r22,r23
> + ;;
> + cmp.eq p8,p0=r23,r0
> +#else
> ;;
> cmp.eq p8,p0=((VIRT_FRAME_TABLE_ADDR>>56)&0xff)-0x100,r22
> +#endif
> (p8) br.cond.sptk frametable_miss ;;
> #endif
> // If it is not a Xen address, handle it via page_fault.
> diff -r 3e4fa8b5b245 xen/arch/ia64/xen/xenmem.c
> --- a/xen/arch/ia64/xen/xenmem.c Tue Sep 12 11:43:22 2006 -0600
> +++ b/xen/arch/ia64/xen/xenmem.c Wed Sep 20 17:14:01 2006 +0200
> @@ -76,13 +76,13 @@ alloc_dir_page(void)
> alloc_dir_page(void)
> {
> unsigned long mfn = alloc_boot_pages(1, 1);
> - unsigned long dir;
> + unsigned char *virtual;
> if (!mfn)
> panic("Not enough memory for virtual frame table!\n");
> ++table_size;
> - dir = mfn << PAGE_SHIFT;
> - memset(__va(dir), 0, PAGE_SIZE);
> - return (void *)dir;
> + virtual = __va(mfn << PAGE_SHIFT);
> + memset(virtual, 0, PAGE_SIZE);
> + return virtual;
> }
>
> static inline unsigned long
> _______________________________________________
> Xen-ia64-devel mailing list
> Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-ia64-devel
_______________________________________________
Xen-ia64-devel mailing list
Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ia64-devel
|
Home