Excerpts from Cédric Le Goater's message of June 26, 2020 5:17 pm:
> Adding David,
>
> On 6/25/20 3:11 AM, Michael Ellerman wrote:
>> Nicholas Piggin writes:
>>> KVM supports msgsndp in guests by trapping and emulating the
>>> instruction, so it was decided to always use XIVE for IPIs if it is
>
Adding David,
On 6/25/20 3:11 AM, Michael Ellerman wrote:
> Nicholas Piggin writes:
>> KVM supports msgsndp in guests by trapping and emulating the
>> instruction, so it was decided to always use XIVE for IPIs if it is
>> available. However on PowerVM systems, msgsndp can be used and gives
>> be
>>> An option vector (or dt-cpu-ftrs) could be defined to disable msgsndp
>>> to get KVM performance back.
>
> An option vector would require a PAPR change. Unless the architecture
> reserves some bits for the implementation, but I don't think so. Same
> for CAS.
>
>> Qemu/KVM populates /proc/de
[ ... ]
>>> An option vector (or dt-cpu-ftrs) could be defined to disable msgsndp
>>> to get KVM performance back.
>
> An option vector would require a PAPR change. Unless the architecture
> reserves some bits for the implementation, but I don't think so. Same
> for CAS.
>
>> Qemu/KVM populate
