[PATCH] powerpc: book3s: kvm: Use the saved dsisr and dar values

[Alexander Graf]

On 11.11.2013, at 15:02, Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com> wrote:

> From: "Aneesh Kumar K.V" <aneesh.kumar at linux.vnet.ibm.com>
> 
> Don't try to compute these values.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>
> ---
> 
> 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 at suse.de>
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 at suse.de>
    Signed-off-by: Avi Kivity <avi at redhat.com>

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 :).


Alex