Re: [Qemu-devel] [PATCH V8 RESEND 4/8] pci.c: Add pci_check_bar_overlap

[Anthony PERARD <anthony.perard@citrix.com>]

On 19/03/12 13:15, Michael S. Tsirkin wrote:
> On Fri, Mar 16, 2012 at 04:54:18PM +0000, Anthony PERARD wrote:
>> From: Yuji Shimada<shimada-yxb@necst.nec.co.jp>
>>
>> This function helps Xen PCI Passthrough device to check for overlap.
>>
>> Signed-off-by: Yuji Shimada<shimada-yxb@necst.nec.co.jp>
>> Signed-off-by: Anthony PERARD<anthony.perard@citrix.com>
>
> It seems that what's called for here really is
> using the new memory region infrastructure.
> That handles overlap etc nicely.
>
> That said, I don't mind, but would prefer to
> keep this mess outside the pci core. See below.
>
>> ---
>>   hw/pci.c |   50 ++++++++++++++++++++++++++++++++++++++++++++++++++
>>   hw/pci.h |    5 +++++
>>   2 files changed, 55 insertions(+), 0 deletions(-)
>>
>> diff --git a/hw/pci.c b/hw/pci.c
>> index 38e1de5..f950b4e 100644
>> --- a/hw/pci.c
>> +++ b/hw/pci.c
>> @@ -1992,6 +1992,56 @@ MemoryRegion *pci_address_space_io(PCIDevice *dev)
>>       return dev->bus->address_space_io;
>>   }
>>
>> +/* This function
>
> Comment blocks start with /* */
>
>> checks if an io_region overlap an io_region from another
>
> overlaps
>
>> + * device.  The io_region to check is provide with (addr, size and type)
>
> provided
>
>> + * A callback can be provide and will be called for every region that is
>
> provided
>
>> + * overlapped.
>> + * The return value indicate if the region is overlappsed */
>
> indicates
>
>
>> +bool pci_check_bar_overlap(PCIDevice *device,
>> +                           pcibus_t addr, pcibus_t size, uint8_t type,
>> +                           void (*c)(void *o, const PCIDevice *d, int index),
>> +                           void *opaque)
>
> IMO this is inlikely to be needed by anyone except Xen.
> How about a generic pci_foreach_device and let Xen
> implement the hacks internally.

Ok, this should be better, I'll work on that.

Thanks,

>> +{
>> +    PCIBus *bus = device->bus;
>> +    int i, j;
>> +    bool rc = false;
>> +
>> +    for (i = 0; i<  ARRAY_SIZE(bus->devices); i++) {
>> +        PCIDevice *d = bus->devices[i];
>> +        if (!d) {
>> +            continue;
>> +        }
>> +
>> +        if (d->devfn == device->devfn) {
>> +            continue;
>> +        }
>> +
>> +        /* xxx: This ignores bridges. */
>> +        for (j = 0; j<  PCI_NUM_REGIONS; j++) {
>> +            PCIIORegion *r =&d->io_regions[j];
>> +
>> +            if (!r->size) {
>> +                continue;
>> +            }
>> +            if ((type&  PCI_BASE_ADDRESS_SPACE_IO)
>> +                != (r->type&  PCI_BASE_ADDRESS_SPACE_IO)) {
>> +                continue;
>> +            }
>> +
>> +            if (ranges_overlap(addr, size, r->addr, r->size)) {
>> +                if (c) {
>> +                    c(opaque, d, j);
>> +                    rc = true;
>> +                } else {
>> +                    return true;
>> +                }
>> +            }
>> +        }
>> +    }
>> +
>> +    return rc;
>> +}
>> +
>>   static void pci_device_class_init(ObjectClass *klass, void *data)
>>   {
>>       DeviceClass *k = DEVICE_CLASS(klass);
>> diff --git a/hw/pci.h b/hw/pci.h
>> index 4f19fdb..cbd04e1 100644
>> --- a/hw/pci.h
>> +++ b/hw/pci.h
>> @@ -628,4 +628,9 @@ extern const VMStateDescription vmstate_pci_device;
>>       .offset     = vmstate_offset_pointer(_state, _field, PCIDevice), \
>>   }
>>
>> +bool pci_check_bar_overlap(PCIDevice *dev,
>> +                           pcibus_t addr, pcibus_t size, uint8_t type,
>> +                           void (*c)(void *o, const PCIDevice *d, int index),
>> +                           void *opaque);
>> +
>>   #endif
>> --
>> Anthony PERARD


-- 
Anthony PERARD