Re: [Qemu-devel] [PATCH 1/2] Add HPET emulation to qemu (v4)

[Beth Kon]

On Fri, 2008-11-14 at 03:12 +0000, Jamie Lokier wrote:
> Beth Kon wrote:
> > - enabled 64-bit capability (after discovering that OS is 
> >   warned in HPET spec about possibility that a 64-bit read may 
> >   be implemented as two 32-bit reads).
> 
> It's in the spec, but are there any real x86_64 machines where 64-bit
> HPET read would be translated into two 32-bit reads?  I'm wondering if
> some OSes ssume reading HPET with a 64-bit read on x86_64 is atomic,
> because that might be true.  Linux seems to use HPET in 32-bit mode so
> that's safe (I checked Linux 2.6.26).
> 
> -- Jamie
> 
Hmm, good point. Maybe it would be safer to leave it at 32 bits. 
> 
-- 
Elizabeth Kon (Beth)
IBM Linux Technology Center
Open Hypervisor Team
email: address@hidden