From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: Alexander Graf <agraf@suse.de>
Cc: Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org,
"kvm@vger.kernel.org mailing list" <kvm@vger.kernel.org>
Subject: Re: [PATCH] powerpc: book3s: kvm: Use the saved dsisr and dar values
Date: Thu, 19 Dec 2013 12:32:50 +0530 [thread overview]
Message-ID: <87bo0d9vc5.fsf@linux.vnet.ibm.com> (raw)
In-Reply-To: <0AB88010-F2B7-44A1-8FA9-2A40079706BB@suse.de>
Alexander Graf <agraf@suse.de> writes:
> On 11.11.2013, at 15:02, Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> wrote:
>
>> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>>
>> Don't try to compute these values.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@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@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@suse.de>
> Signed-off-by: Avi Kivity <avi@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 :).
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.
-aneesh
next prev parent reply other threads:[~2013-12-19 7:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-11 14:02 [PATCH] powerpc: book3s: kvm: Use the saved dsisr and dar values Aneesh Kumar K.V
2013-11-28 4:06 ` Paul Mackerras
2013-12-18 21:44 ` Alexander Graf
2013-12-19 2:26 ` Paul Mackerras
2013-12-19 7:02 ` Aneesh Kumar K.V [this message]
2013-12-19 12:35 ` Alexander Graf
2013-12-20 4:37 ` Aneesh Kumar K.V
2013-12-20 6:38 ` Alexander Graf
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