Marcelo Tosatti wrote: > Anthony, > > Both virtio-net and virtio-block currently register PCI IO space regions > that are not power of two in size. > > The decoding process to discover the size of a PCI resource expects it > to be a power of two. The PCI controller masks the size out of what is > written into > > config_space + 0x10 + (4 * region_num) > > The result is that the size is calculated and registered erroneously > by the OS: > > [EMAIL PROTECTED] ~]# cat /proc/ioports | grep virtio > c200-c203 : virtio-pci > > This is a virtio-block device whose BAR0 has length (16+20)-1, not 4. > > BAR0: I/O at 0xc200 [0xc223]. > > I suggest forcing the size to be power of two as follows: > >
A quick grep of the source show that virtio seems to be the only device that isn't behaving here. I suggest modifying the virtio.c to always use a power of two and then perhaps adding a check in hw/pci.c to validate that the registered region is a power of two in size. Regards, Anthony Liguori > Index: kvm-userspace.hotplug2/qemu/hw/pci.c > =================================================================== > --- kvm-userspace.hotplug2.orig/qemu/hw/pci.c > +++ kvm-userspace.hotplug2/qemu/hw/pci.c > @@ -236,6 +236,13 @@ void pci_register_io_region(PCIDevice *p > > if ((unsigned int)region_num >= PCI_NUM_REGIONS) > return; > + > + /* IO region size must be power of two */ > + if (type == PCI_ADDRESS_SPACE_IO && (size & (size-1))) { > + size = size << 1; > + size &= size-1; > + } > + > r = &pci_dev->io_regions[region_num]; > r->addr = -1; > r->size = size; > > ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel