> Am 20.12.2013 um 05:37 schrieb "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>: > > Alexander Graf <agraf@xxxxxxx> writes: > >>> Am 19.12.2013 um 08:02 schrieb "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>: >>> >>> Alexander Graf <agraf@xxxxxxx> writes: >>> >>>>> On 11.11.2013, at 15:02, Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> wrote: >>>>> >>>>> From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx> >>>>> >>>>> Don't try to compute these values. >>>>> >>>>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> >>>>> --- >>>>> >>>>> NOTE: I am not sure why we were originally computing dsisr and dar. So may be >>>>> we need a variant of this patch. But with this and the additional patch >>>>> "powerpc: book3s: PR: Enable Little Endian PR guest" I am able to get a Little Endian >>>>> PR guest to boot. >>>> >>>> It's quite easy to find out - git blame tells you all the history and points you to commit ca7f4203b. >>>> >>>> commit ca7f4203b9b66e12d0d9968ff7dfe781f3a9695a >>>> Author: Alexander Graf <agraf@xxxxxxx> >>>> Date: Wed Mar 24 21:48:28 2010 +0100 >>>> >>>> KVM: PPC: Implement alignment interrupt >>>> >>>> Mac OS X has some applications - namely the Finder - that require alignment >>>> interrupts to work properly. So we need to implement them. >>>> >>>> But the spec for 970 and 750 also looks different. While 750 requires the >>>> DSISR and DAR fields to reflect some instruction bits (DSISR) and the fault >>>> address (DAR), the 970 declares this as an optional feature. So we need >>>> to reconstruct DSISR and DAR manually. >>>> >>>> Signed-off-by: Alexander Graf <agraf@xxxxxxx> >>>> Signed-off-by: Avi Kivity <avi@xxxxxxxxxx> >>>> >>>> Read this as "on 970, alignment interrupts don't give us DSISR and DAR of the faulting instruction" as otherwise I wouldn't have implemented it. >>>> >>>> So this is clearly a nack on this patch :). >>> >>> I can possibly do a if (cpu_has_feature(CPU_FTR_ARCH_201)). But do we need >>> to do that ? According to Paul we should always find DAR. >> >> Paul only mentioned DAR, not DSISR. Please verify whether 970 gives us a proper DAR value - we can then remove that part. >> >> But for DSISR I'm not convinced CPUs above 970 handle this >> correctly. So we would at least need a guest cpu check to find out >> whether the vcpu expects a working dsisr and emulate it then. > >> >> I don't really fully understand the problem though. Why does the >> calculation break at all for you? > > > IIRC this was to get little endian PR setup to work. This is to avoid > handling new instructions, because in little endian mode we get > alignment interrupt for a larger instructon set Ok, please limit dar/dsisr calculation to book3s_32 vcpus then :). Alex > > -aneesh > -- 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
