On 10/07/2012 12:13 PM, Avi Kivity wrote: > On 10/05/2012 06:24 PM, Blue Swirl wrote: >> >> I'd suppose addressing devices in the bus could be implemented more >> efficiently with better use of memory API, now some of it is >> reimplemented. Maybe Avi can propose something? > > Luckily the low-order bits are used for offsets, and the high-order bits > are used for selecting the sub-device. > > So you could easily have > > struct IPackDevice { > DeviceState qdev; > int32_t slot; > /* IRQ objects for the IndustryPack INT0# and INT1# */ > qemu_irq *irq; > MemoryRegion io_space; > MemoryRegion id_space; > MemoryRegion int_space; > MemoryRegion mem8_space; /* for las3 */ > MemoryRegion mem16_space; /* for las2 */ > }; > > The PCI device would then just map each space (with > memory_region_add_subregion()) into las1/las2/las3 such that the high > bits select the device/space. The low bits would automatically become > the offset into the space.
Note: you can easily verify that the mapping is correct with 'info mtree'. You should see something like: pci: ... xxxxxxxx-xxxxxxxx las1 xxxxxxxx-xxxxxxxxx ip0-io xxxxxxxx-xxxxxxxxx ip0-id xxxxxxxx-xxxxxxxxx ip0-int xxxxxxxx-xxxxxxxxx ip1-io xxxxxxxx-xxxxxxxxx ip1-id xxxxxxxx-xxxxxxxxx ip1-int xxxxxxxx-xxxxxxxx las2 xxxxxxxx-xxxxxxxx ip0-mem16 xxxxxxxx-xxxxxxxx ip1-mem16 with the addresses relative to the pci address space. -- error compiling committee.c: too many arguments to function