Re: [Qemu-devel] [PATCH] pci: set memory type for memory behind the bridge

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Tue, 2012-02-21 at 15:56 +0100, Alexander Graf wrote:
> On 02/21/2012 02:57 PM, Michael S. Tsirkin wrote:
> > As we make upper bits in IO and prefetcheable memory
> > registers writeable, we should declare support
> > for 64 bit prefetcheable memory and 32 bit io
> > in the bridge.
> >
> > This changes the default for apb, dec, but I'm guessing
> > they got the defaults wrong by accident.
> > Alternatively, we could let bridges declare lack of
> > 64 bit support and make the upper bits read-only zero.
> >
> > With this applied, we can drop these bits
> > from express code.
> 
> Ben, you know these devices better than us. Any comments? :)

I don't know that code very well, but Michael's explanation at least
makes sense to me :-)

Cheers,
Ben.

> Alex
> 
> > Reported-by: Gerd Hoffmann<kraxel@redhat.com>
> > Signed-off-by: Michael S. Tsirkin<mst@redhat.com>
> >
> > Could someone familiar with apb,dec ack this please?
> >
> > ---
> >   hw/pci.c |   15 +++++++++++++--
> >   1 files changed, 13 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/pci.c b/hw/pci.c
> > index 31d6a5f..3ca5f4c 100644
> > --- a/hw/pci.c
> > +++ b/hw/pci.c
> > @@ -611,7 +611,7 @@ static void pci_init_w1cmask(PCIDevice *dev)
> >                    PCI_STATUS_SIG_SYSTEM_ERROR | PCI_STATUS_DETECTED_PARITY);
> >   }
> >
> > -static void pci_init_wmask_bridge(PCIDevice *d)
> > +static void pci_init_mask_bridge(PCIDevice *d)
> >   {
> >       /* PCI_PRIMARY_BUS, PCI_SECONDARY_BUS, PCI_SUBORDINATE_BUS and
> >          PCI_SEC_LETENCY_TIMER */
> > @@ -632,6 +632,14 @@ static void pci_init_wmask_bridge(PCIDevice *d)
> >       /* PCI_PREF_BASE_UPPER32 and PCI_PREF_LIMIT_UPPER32 */
> >       memset(d->wmask + PCI_PREF_BASE_UPPER32, 0xff, 8);
> >
> > +    /* Supported memory and i/o types */
> > +    d->config[PCI_IO_BASE] |= PCI_IO_RANGE_TYPE_32;
> > +    d->config[PCI_IO_LIMIT] |= PCI_IO_RANGE_TYPE_32;
> > +    pci_word_test_and_set_mask(d->config + PCI_PREF_MEMORY_BASE,
> > +                               PCI_PREF_RANGE_TYPE_64);
> > +    pci_word_test_and_set_mask(d->config + PCI_PREF_MEMORY_LIMIT,
> > +                               PCI_PREF_RANGE_TYPE_64);
> > +
> >   /* TODO: add this define to pci_regs.h in linux and then in qemu. */
> >   #define  PCI_BRIDGE_CTL_VGA_16BIT	0x10	/* VGA 16-bit decode */
> >   #define  PCI_BRIDGE_CTL_DISCARD		0x100	/* Primary discard timer */
> > @@ -654,6 +662,9 @@ static void pci_init_wmask_bridge(PCIDevice *d)
> >        * completeness. */
> >       pci_set_word(d->w1cmask + PCI_BRIDGE_CONTROL,
> >                    PCI_BRIDGE_CTL_DISCARD_STATUS);
> > +    d->cmask[PCI_IO_BASE] |= PCI_IO_RANGE_TYPE_MASK;
> > +    pci_word_test_and_set_mask(d->cmask + PCI_PREF_MEMORY_BASE,
> > +                               PCI_PREF_RANGE_TYPE_MASK);
> >   }
> >
> >   static int pci_init_multifunction(PCIBus *bus, PCIDevice *dev)
> > @@ -775,7 +786,7 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
> >       pci_init_wmask(pci_dev);
> >       pci_init_w1cmask(pci_dev);
> >       if (pc->is_bridge) {
> > -        pci_init_wmask_bridge(pci_dev);
> > +        pci_init_mask_bridge(pci_dev);
> >       }
> >       if (pci_init_multifunction(bus, pci_dev)) {
> >           pci_config_free(pci_dev);