Re: [Qemu-devel] [PATCH 4/6] pci: add helper to retrieve the 64-bit range

[Michael S. Tsirkin]

On Tue, Sep 10, 2013 at 07:05:10PM +0200, Igor Mammedov wrote:
> On Tue, 10 Sep 2013 16:50:41 +0300
> "Michael S. Tsirkin" <address@hidden> wrote:
> 
> > On Tue, Sep 10, 2013 at 03:40:03PM +0200, Igor Mammedov wrote:
> > > On Wed, 4 Sep 2013 13:48:37 +0300
> > > "Michael S. Tsirkin" <address@hidden> wrote:
> > > 
> > > > Signed-off-by: Michael S. Tsirkin <address@hidden>
> > > > ---
> > > >  include/hw/pci/pci.h |  1 +
> > > >  hw/pci/pci.c         | 43 +++++++++++++++++++++++++++++++++++++++++++
> > > >  2 files changed, 44 insertions(+)
> > > > 
> > > > diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> > > > index 2374aa9..7be93ae 100644
> > > > --- a/include/hw/pci/pci.h
> > > > +++ b/include/hw/pci/pci.h
> > > > @@ -397,6 +397,7 @@ const char *pci_root_bus_path(PCIDevice *dev);
> > > >  PCIDevice *pci_find_device(PCIBus *bus, int bus_num, uint8_t devfn);
> > > >  int pci_qdev_find_device(const char *id, PCIDevice **pdev);
> > > >  PCIBus *pci_get_bus_devfn(int *devfnp, PCIBus *root, const char 
> > > > *devaddr);
> > > > +void pci_bus_get_w64_range(PCIBus *bus, Range *range);
> > > >  
> > > >  int pci_parse_devaddr(const char *addr, int *domp, int *busp,
> > > >                        unsigned int *slotp, unsigned int *funcp);
> > > > diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> > > > index 8c33352..d9f9bdf 100644
> > > > --- a/hw/pci/pci.c
> > > > +++ b/hw/pci/pci.c
> > > > @@ -2257,6 +2257,49 @@ void pci_setup_iommu(PCIBus *bus, PCIIOMMUFunc 
> > > > fn, void *opaque)
> > > >      bus->iommu_opaque = opaque;
> > > >  }
> > > >  
> > > > +static void pci_dev_get_w64(PCIBus *b, PCIDevice *dev, void *opaque)
> > > > +{
> > > > +    Range *range = opaque;
> > > > +    PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(dev);
> > > > +    uint16_t cmd = pci_get_word(dev->config + PCI_COMMAND);
> > > > +    int r;
> > > > +
> > > > +    if (!(cmd & PCI_COMMAND_MEMORY)) {
> > > > +        return;
> > > > +    }
> > > > +
> > > > +    if (pc->is_bridge) {
> > > > +        pcibus_t base = pci_bridge_get_base(dev, 
> > > > PCI_BASE_ADDRESS_MEM_PREFETCH);
> > > what guaranties that 'base' won't be below 4Gb
> > 
> > Hmm, this needs some thought.
> > 
> > > and be above '4Gb + above_4g_mem_size'?
> > 
> > This one is harmless - guest will only hurt itself if
> > it misconfigures the bridge like this.
> 
> start of w64 is hardcoded in QEMU and Seabios as (4Gb+above_4gb_ram_size),
> so maybe there is no need to update/modify it at all?
> 

Well the point is to have QEMU obey whatever bios does.
seabios hardcodes the start of window but some other
firmware might not.


> > 
> > > > +        pcibus_t limit = pci_bridge_get_limit(dev, 
> > > > PCI_BASE_ADDRESS_MEM_PREFETCH);
> > > > +
> > > > +        if (limit >= base) {
> > > > +            Range pref_range;
> > > > +            pref_range.begin = base;
> > > > +            pref_range.end = limit + 1;
> > > > +            range_extend(range, &pref_range);
> > > > +        }
> > > > +    }
> > > > +    for (r = 0; r < PCI_NUM_REGIONS; ++r) {
> > > > +        PCIIORegion *region = &dev->io_regions[r];
> > > > +        Range region_range;
> > > > +
> > > > +        if (!region->size ||
> > > > +            (region->type & PCI_BASE_ADDRESS_SPACE_IO) ||
> > > > +            !(region->type & PCI_BASE_ADDRESS_MEM_TYPE_64)) {
> > > > +            continue;
> > > > +        }
> > > > +        region_range.begin = pci_get_quad(dev->config + pci_bar(dev, 
> > > > r));
> > > > +        region_range.end = region_range.begin + region->size;
> > > > +        range_extend(range, &region_range);
> > > > +    }
> > > > +}
> > > > +
> > > > +void pci_bus_get_w64_range(PCIBus *bus, Range *range)
> > > > +{
> > > > +    range->begin = range->end = 0;
> > > > +    pci_for_each_device_under_bus(bus, pci_dev_get_w64, range);
> > > > +}
> > > > +
> > > >  static const TypeInfo pci_device_type_info = {
> > > >      .name = TYPE_PCI_DEVICE,
> > > >      .parent = TYPE_DEVICE,