On Thu, Aug 4, 2011 at 1:28 AM, Jan Kiszka <jan.kiszka@xxxxxxxxxxx> wrote: > On 2011-08-04 05:14, Konrad Rzeszutek Wilk wrote: >>>>>>> and kvm does not want to go further. dmesg, /proc/iomem and lspci are at >>>>>>> the end of this email. >>>>>>> The memory reserved by BIOS-e820 >>>>>>> [ 0.000000] BIOS-e820: 00000000fa000000 - 00000000fc000000 >>>>>>> (reserved) >>>>>>> Quadro 2000 is 05:00.0 and its conflicting BAR is >>>>>>> Region 3: Memory at f8000000 (64-bit, prefetchable) [disabled] >>>>>>> [size=64M] >>>>>>> and its upstream bridge 00:1c.00 >>> OK, if it's safe to ignore for PCI allocations, then ignore the >>> reservation. But I think that should be done automatically if somehow >>> possible, not by the user via a kernel parameter. >>> >>> Is there a simple way to test such a policy without significant >>> refactoring of the e820 code? >> >> Why not just make the kvm PCI passthrough code check the MMIO >> of the card and make an "gap" in the E820 for that region. In essence >> creating a PCI I/O region? >> >> Why does QEMU setup up that reserved region? Can it move it? > > I really don't think this is KVM business. The fact that also nouveau > and nvidia's blob complain or even stumble (Maxim is checking if the > hack also heals the latter) and both are using a standard PCI core > service to request the card resources strongly suggests that the problem > should not be attacked by some ad-hoc workaround in KVM. I tend to agree that it would be better to have a more general change in the way we handle E820 because there are similar issues that don't involve KVM. For example, see https://bugzilla.kernel.org/show_bug.cgi?id=31602#c32; there we need to reserve a PNP device region of 0xd0000000-0xdfffffff, but the reservation fails because we have a previous 0xd0000000-0xd3ffffff reservation from E820. We might hack around it for now by doing the PNP reservation in pieces, but I think it would be cleaner to do something different with the E820 stuff. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
