Re: [Qemu-devel] [PATCH v2] piix: fix 32bit pci hole

["Michael S. Tsirkin" <mst@redhat.com>]

On Fri, Jan 10, 2014 at 09:28:39PM +0100, Laszlo Ersek wrote:
> On 11/28/13 17:03, Laszlo Ersek wrote:
> > Mike,
> > 
> > On 11/27/13 12:57, Gerd Hoffmann wrote:
> >> Make the 32bit pci hole start at end of ram, so all possible address
> >> space is covered.  Of course the firmware can use less than that.
> >> Leaving space unused is no problem, mapping pci bars outside the
> >> hole causes problems though.
> >>
> >> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> >> ---
> >>  hw/pci-host/piix.c | 10 +---------
> >>  1 file changed, 1 insertion(+), 9 deletions(-)
> >>
> >> diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
> >> index edc974e..8e41ac1 100644
> >> --- a/hw/pci-host/piix.c
> >> +++ b/hw/pci-host/piix.c
> >> @@ -345,15 +345,7 @@ PCIBus *i440fx_init(PCII440FXState **pi440fx_state,
> >>      f->ram_memory = ram_memory;
> >>  
> >>      i440fx = I440FX_PCI_HOST_BRIDGE(dev);
> >> -    /* Set PCI window size the way seabios has always done it. */
> >> -    /* Power of 2 so bios can cover it with a single MTRR */
> >> -    if (ram_size <= 0x80000000) {
> >> -        i440fx->pci_info.w32.begin = 0x80000000;
> >> -    } else if (ram_size <= 0xc0000000) {
> >> -        i440fx->pci_info.w32.begin = 0xc0000000;
> >> -    } else {
> >> -        i440fx->pci_info.w32.begin = 0xe0000000;
> >> -    }
> >> +    i440fx->pci_info.w32.begin = pci_hole_start;
> >>  
> >>      memory_region_init_alias(&f->pci_hole, OBJECT(d), "pci-hole", f->pci_address_space,
> >>                               pci_hole_start, pci_hole_size);
> >>
> > 
> > please pick this up for 1.7.1.
> > 
> > 1.7.0 has been released without this patch, also without etc/pci-info,
> > but with etc/acpi/tables.
> > 
> > For OVMF to work with "etc/acpi/tables" correctly, with eg. a guest RAM
> > size of 2560MB, OVMF needs:
> > - either this patch in qemu, or
> > - etc/pci-info (which won't come back), or
> > - a hack in OVMF that mimicks the same 0x80000000/0xc0000000/0xe0000000
> >   logic (which I won't add).
> 
> Nominating this for v1.7.1 again.
> 
> The qemu-2.0 version (ie. a forward-port) of this patch has been merged as
> 
>   ddaaefb piix: fix 32bit pci hole
> 
> If necessary I can resubmit the v1.7.1 patch.
> 
> Thanks,
> Laszlo


It seems cleaner to backport this into stable.
Mike, can you pick this up please?

-- 
MST