Re: [PATCH] x86: fix ordering constraints on crX read/writes

[Avi Kivity]

On 07/15/2010 03:28 AM, Zachary Amsden wrote:
> >   static inline void native_write_cr2(unsigned long val)
> >   {
> > -    asm volatile("mov %0,%%cr2": : "r" (val), "m" (__force_order));
> > +    asm volatile("mov %1,%%cr2": "+m" (__force_order) : "r" (val) : 
> > "memory");
> >   }
>
>
> You don't need the memory clobber there.  Technically, this should 
> never be used, however.

kvm writes cr2 in order to present the correct value to the guest.  It 
doesn't use native_write_cr2(), however.

--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/