Re: [Qemu-devel] [PATCH v2] exec.c: Fix subpage memory access to RAM MemoryRegion

[Gleb Natapov]

On Thu, Dec 01, 2011 at 11:54:33AM +0200, Avi Kivity wrote:
> On 12/01/2011 11:47 AM, Gleb Natapov wrote:
> > On Thu, Dec 01, 2011 at 11:41:52AM +0200, Avi Kivity wrote:
> > > On 12/01/2011 11:37 AM, Gleb Natapov wrote:
> > > > > 
> > > > > Looks reasonable.  Should go into 1.1.  Should we backport it to
> > > > > 1.0.blah?  From 95c318f's description, it doesn't happen in normal
> > > > > circumstances.
> > > > > 
> > > > To reproduce that I mappped subpage PCI bar over RAM IIRC. 
> > > 
> > > In qemu 1.0, you can no longer do that (the pci bridge will not let the
> > > BAR override the RAM).
> > > 
> >
> > Hmm, if this is how real HW work then problem solved :) (different HW can
> > behave differently, but it is reasonable to assume that on a PC memory
> > access below TOM will be redirected to memory controller no matter what)
> > So what is the motivation for Andreas patch than?
> >
> 
> He's not emulating pc hardware.
> 
That's not a crime in itself :) What HW he encountered this problem on?
What scenario? How likely is this scenario on that HW (my comment for
95c318f which you are referring to above was for PC)? And if KVM is
supported on that HW my comment about KVM still applies.

--
                        Gleb.