WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] xen and agpgart

On Sat, Sep 04, 2004 at 05:47:36AM +0100, Keir Fraser wrote:
> Somehow you are ending up in the following code in the following code
> in __change_page_attr (arch/i386/mm/pageattr.c):
> 
>       if (cpu_has_pse && (page_count(kpte_page) == 1)) {
>               list_add(&kpte_page->lru, &df_list);
>               revert_page(kpte_page, address);
>       } 
> 
> This ought to be impossible, as cpu_has_pse should be 0.
> Add some debug printing around that code -- e.g., print the value of
> cpu_has_pse, and also the contents of e.g.,
> boot_cpu_data.x86_capability[0], boot_cpu_data.x86_capability[1].

I've confirmed that this is infact the codepath that's executing.
I also catted /proc/cpuinfo and the "pse" flag is listed there.

If it helps, my setup here is an IBM Thinkpad T40p which has a Pentium M
1600MHz in it (cpuinfo is included below).

> Perhaps the capability flags are getting corrupted - I think the value
> must be correct at boot time or you would crash while booting!

I examined the values in /proc/cpuinfo after boot, I'll dump the flags
earlier in the boot process and see if it's correct then...

I tested for PSE immediately after the memcpy() at the top of setup_arch()
and it is set there.

Here is the cpuinfo from within Xen:

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 9
model name      : Intel(R) Pentium(R) M processor 1600MHz
stepping        : 5
cpu MHz         : 1594.870
cache size      : 1024 KB
fdiv_bug        : no
hlt_bug         : yes
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 2
wp              : yes
flags           : fpu vme de pse tsc msr mce cx8 apic sep mtrr pge mca cmov pat 
clflush dts acpi mmx fxsr sse sse2 tm pbe tm2 est
bogomips        : 3185.04

Outside of Xen, the differences I see are "hlt_bug : no" instead of yes,
and outside I lack the flags "apic sep"

> Meanwhile I've checked in a fix for wbinvd. I've fixed the wbinvd()
> macro in system.h, but agp.h uses the instruction directly. You'll
> have to patch that file yourself -- really a patch ought to be sent to
> the maintainer, but I'll wait until I've fixed the broken uses of
> ioremap_nocache in various GART drivers.

This sounds good to me.

                                -- Gerald


-------------------------------------------------------
This SF.Net email is sponsored by BEA Weblogic Workshop
FREE Java Enterprise J2EE developer tools!
Get your free copy of BEA WebLogic Workshop 8.1 today.
http://ads.osdn.com/?ad_id=5047&alloc_id=10808&op=click
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel