Il Thu, Jun 14, 2007 at 11:26:29AM +0300, Avi Kivity ha scritto:
> Luca Tettamanti wrote:
> >With GOOD_APIC apic_read_around is a nop, while apic_write_around is a
> >normal write. With !GOOD_APIC apic_write_around writes to the APIC reg
> >using xchg. With !GOOD_APIC and this patch:
> >
> >--- include/asm-i386/apic.h~ 2007-04-26 05:08:32.000000000 +0200
> >+++ include/asm-i386/apic.h 2007-06-13 22:35:00.000000000 +0200
> >@@ -56,7 +56,8 @@
> > static __inline fastcall void native_apic_write_atomic(unsigned long reg,
> > unsigned long v)
> > {
> >- xchg((volatile unsigned long *)(APIC_BASE+reg), v);
> >+// xchg((volatile unsigned long *)(APIC_BASE+reg), v);
> >+ *((volatile unsigned long *)(APIC_BASE+reg)) = v;
> > }
> >
> > static __inline fastcall unsigned long native_apic_read(unsigned long reg)
> >
> >The kernel boots fine.
> >
>
> Looking at the xchg emulation code, it seems fine, but clearly it
> isn't.
Btw, I've put a printk in x86_emulate.c, where it prepares the operands
for the xchg operations: all the write_atomic are hitting this point,
so the write is lost somewhere in cmpxchg_emulated->write_emulated.
Luca
--
Il dottore mi ha detto di smettere di fare cene intime per quattro.
A meno che non ci siamo altre tre persone.
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