[PATCH v4 12/14] ARM64: KVM: vgic_elrsr and vgic_eisr need to be byteswapped in BE case

[Victor Kamensky]

On 14 June 2014 08:04, Christoffer Dall <christoffer.dall at linaro.org> wrote:
> On Thu, Jun 12, 2014 at 09:30:11AM -0700, Victor Kamensky wrote:
>> On arm64 'u32 vgic_eisr[2];' and 'u32 vgic_elrsr[2]' are accessed as
>> one 'unsigned long *' bit fields, which has 64bit size. So we need to
>> swap least significant word with most significant word when code reads
>> those registers from h/w.
>>
>> Signed-off-by: Victor Kamensky <victor.kamensky at linaro.org>
>> ---
>>  arch/arm64/kvm/hyp.S | 7 +++++++
>>  1 file changed, 7 insertions(+)
>>
>> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
>> index 0620691..5035b41 100644
>> --- a/arch/arm64/kvm/hyp.S
>> +++ b/arch/arm64/kvm/hyp.S
>> @@ -415,10 +415,17 @@ CPU_BE( rev     w11, w11 )
>>       str     w4, [x3, #VGIC_CPU_HCR]
>>       str     w5, [x3, #VGIC_CPU_VMCR]
>>       str     w6, [x3, #VGIC_CPU_MISR]
>> +#ifndef CONFIG_CPU_BIG_ENDIAN
>>       str     w7, [x3, #VGIC_CPU_EISR]
>>       str     w8, [x3, #(VGIC_CPU_EISR + 4)]
>>       str     w9, [x3, #VGIC_CPU_ELRSR]
>>       str     w10, [x3, #(VGIC_CPU_ELRSR + 4)]
>> +#else
>> +     str     w7, [x3, #(VGIC_CPU_EISR + 4)]
>> +     str     w8, [x3, #VGIC_CPU_EISR]
>> +     str     w9, [x3, #(VGIC_CPU_ELRSR + 4)]
>> +     str     w10, [x3, #VGIC_CPU_ELRSR]
>> +#endif
>>       str     w11, [x3, #VGIC_CPU_APR]
>>
>>       /* Clear GICH_HCR */
>> --
>> 1.8.1.4
>>
> I thought Marc had something here which allowed you to deal with the
> conversion in the accessor functions and avoid this patch?

Christoffer, I appreciate your review comments.

I think I was missing something. Yes, Marc mentioned in [1] about
his new changes in vgic3 series. But just after rereading it now, I
realized that he was suggesting to pick up his commits and add
them to this series. Is it my right understanding that they should
be [2] and [3] ... looking a bit closer to it, it seems that [4] is needed
as well. I am concerned that I don't understand all dependencies
and impact of those. Wondering about other way around. When vgic3
series introduced could we just back off above change and do it in
new right way?

[1] https://lists.cs.columbia.edu/pipermail/kvmarm/2014-May/009618.html
[2] https://lists.cs.columbia.edu/pipermail/kvmarm/2014-May/009475.html
[3] https://lists.cs.columbia.edu/pipermail/kvmarm/2014-May/009472.html
[4] https://lists.cs.columbia.edu/pipermail/kvmarm/2014-May/009473.html

Other question: I was testing all this directly on vanilla v3.15, should I
use some other armkvm specific integration branch to make sure it works
with all other in a queue armkvm changes.

In mean time I will try to pick up [4], [2], and [3] into v3.15 and see
how it goes.

Thanks,
Victor

> -Christoffer