"H. Peter Anvin" <hpa@xxxxxxxxx> writes: > On 06/05/2013 03:08 PM, Anthony Liguori wrote: >>> >>> Definitely an option. However, we want to be able to boot from native >>> devices, too, so having an I/O BAR (which would not be used by the OS >>> driver) should still at the very least be an option. >> >> What makes it so difficult to work with an MMIO bar for PCI-e? >> >> With legacy PCI, tracking allocation of MMIO vs. PIO is pretty straight >> forward. Is there something special about PCI-e here? >> > > It's not tracking allocation. It is that accessing memory above 1 MiB > is incredibly painful in the BIOS environment, which basically means > MMIO is inaccessible. Oh, you mean in real mode. SeaBIOS runs the virtio code in 32-bit mode with a flat memory layout. There are loads of ASSERT32FLAT()s in the code to make sure of this. Regards, Anthony Liguori > > -hpa > > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
