On 01/03/2014 08:04 AM, Alexander Graf wrote: > > On 11.12.2013, at 07:47, Alexey Kardashevskiy <a...@ozlabs.ru> wrote: > >> On 12/10/2013 06:47 PM, Greg Kurz wrote: >>> On Tue, 10 Dec 2013 13:43:05 +1100 >>> Alexey Kardashevskiy <a...@ozlabs.ru> wrote: >>>> On 12/10/2013 03:33 AM, Greg Kurz wrote: >>>>> In the past, IO space could not be mapped into the memory address space >>>>> so we introduced a workaround for that. Nowadays it does not look >>>>> necessary so we can remove the workaround and make sPAPR PCI >>>>> configuration simplier. >>>>> >>>>> This workaround has also an evil side effect with virtio devices: >>>>> because all PHBs have their .io region at the same address, the devices >>>>> get mapped in the .io-alias region of every PHB (AKA. mapped multiple >>>>> times). This breaks the ioeventfd feature and causes qemu to abort() >>>>> when running with KVM and asking for more than one PHB: >>>>> >>>>> $ qemu-system-ppc64 -machine type=pseries,accel=kvm -smp 1 -m 4G \ >>>>> -hda /local/greg/images/fedora-be.qcow2 \ >>>>> -device >>>>> virtio-9p-pci,fsdev=fsdev0,mount_tag=share,bus=pci,ioeventfd=on \ >>>>> -fsdev local,security_model=none,id=fsdev0,path=$HOME/share1 \ -device >>>>> spapr-pci-host-bridge,index=15 kvm_mem_ioeventfd_add: error adding >>>>> ioeventfd: File exists Aborted >>>>> >>>>> This will prevent to use virtio and VFIO passthrough at the same time, >>>>> since VFIO needs a dedicated PHB to work on ppc. >>>>> >>>>> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> >>>> >>>> >>>> I have not seen this version yet so please remove me from "SOB". The patch >>>> you replied to was eventually reworked and went to upstream as >>>> 66aab867cedd2a2d81b4d64eff7c3e0f6f272bbf >>>> >>> >>> Hi Alex, >>> >>> I agree you have not seen this version yet... The patch I replied to was my >>> primary source of inspiration and contains these bits, hence the SOB. >>> Anyway, the SOB is now removed until you decide to add one yourself. :) >>> >>>> This one might be correct too but I want to try this first :) >>>> >>> >>> Well, I hope it is. Please try it. >> >> >> Yep. Tried. Looks good, did not break a thing as far as I can tell, even >> VGA works :) >> >> >> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> > > Thanks, applied to ppc-next.
Please read the rest of this thread. It does not visibly break things but with this patch QEMU starts calling unassigned_mem_accepts() (normally silent) which is not a good sign. -- Alexey
