Re: [Qemu-devel] [PATCH for-1.7 0/5] fix address space size issues

[Michael S. Tsirkin]

On Wed, Nov 06, 2013 at 09:54:03PM +0200, Marcel Apfelbaum wrote:
> On Wed, 2013-11-06 at 20:47 +0200, Michael S. Tsirkin wrote:
> > A bug reported by Luiz Capitulino let us to find
> > several bugs in memory address space setup.
> > 
> > One issue is that gdb stub can give us arbitrary addresses
> > and we'll try to access them.
> > Since our lookup ignored high bits in the address,
> > we hit a wrong section and got a crash.
> > In fact, PCI devices can access arbitrary addresses too,
> > so we should just make lookup robust against this case.
> > 
> > Another issue has to do with size of regions.
> > memory API uses UINT64_MAX so say "all 64 bit" but
> > some devices mistakenly used INT64_MAX.
> > 
> > It should not affect most systems in practice as
> > everything should be limited by address space size,
> > but it's an API misuse that we should not keep around,
> > and it will become a problem if a system with 64 bit
> > target address hits this path.
> > 
> > Patch 1 fixes an actual bug.
> > The rest of patches make code cleaner and more robust.
> > 
> > Michael S. Tsirkin (4):
> >   exec: don't ignore high address bits on lookup
> >   pci: fix address space size for bridge
> >   exec: don't ignore high address bits on set
> >   spapr_pci: s/INT64_MAX/UINT64_MAX/
> > 
> > Paolo Bonzini (1):
> >   pc: s/INT64_MAX/UINT64_MAX/
> > 
> >  exec.c              | 9 +++++++++
> >  hw/i386/pc_piix.c   | 2 +-
> >  hw/i386/pc_q35.c    | 2 +-
> >  hw/pci/pci_bridge.c | 2 +-
> >  hw/ppc/spapr_pci.c  | 2 +-
> >  5 files changed, 13 insertions(+), 4 deletions(-)
> > 
> 
> Reviewed-by: Marcel Apfelbaum <address@hidden>
> 

Please don't apply this.

I didn't post the patches - I only sent them to Marcel :)
And the reason is that the assert in exec. detects more bugs with
over-writing page-tables: just run make check.

I think we need to get a handle on them first before applying.

-- 
MST