Re: [PATCH 5/6] KVM: PPC: Book3S HV: Access XICS in BE

Alexander Graf
2014-06-17T08:37:13Z

On 17.06.14 03:02, Paul Mackerras wrote:
> On Wed, Jun 11, 2014 at 12:33:50PM +0200, Alexander Graf wrote:
>> On the exit path from the guest we check what type of interrupt we received
>> if we received one. This means we're doing hardware access to the XICS interrupt
>> controller.
>>
>> However, when running on a little endian system, this access is byte reversed.
>>
>> So let's make sure to swizzle the bytes back again and virtuall make XICS
>> accesses big endian.
> ...
>
>> @@ -2241,7 +2253,8 @@ kvmppc_read_intr:
>> 42: /* It's not an IPI and it's for the host, stash it in the PACA
>> * before exit, it will be picked up by the host ICP driver
>> */
>> - stw r0, HSTATE_SAVED_XIRR(r13)
>> + li r4, HSTATE_SAVED_XIRR
>> + STWX_BE r0, r13, r4
> This is a paca field, not something mandated by PAPR or shared with
> the guest, so why do we need to keep it BE? If you do make it BE,
> don't you also need to fix kvmppc_get_xics_latch()?

Yikes. Yes. Thanks a lot for the catch!

Alex