Re: [Qemu-devel] [PATCH v3 0/3] ppc: Broadcast tlb flush should have global effect

[Nikunj A Dadhania]

Benjamin Herrenschmidt <address@hidden> writes:

> On Mon, 2016-09-12 at 11:18 +0530, Nikunj A Dadhania wrote:
>> PowerPC targets should do tlb invalidation on other cpus on 
>> instructions that expect a global effect.
>> 
>> * ptesync for BookS
>> * tlbsync primarily for BookE
>>   (for BookS make it a nop, as it always come along with ptesync)
>> * tlbivax for other ppc tragets
>> * H_REMOVE, H_BULK_REMOVE and H_PROTECT hcalls in case of pseries
>
> The above is confusing.
>
> The instructions that have global effects are tlbie (BookS) and tlbivax
> (BookE) plus the H_CALLs since they contain a tlbie on a real
> hypervisor.
>
> The ptesync and tlbsync instructions are barriers use to synchronize
> with the global invalidations. That means that we don't need to ensure
> the global invalidations have completed until we hit those barriers.
>
> We typically use them as a way to "batch" the invalidations in TCG.

Sure, will updated. I mixed up the delayed flush with instructions.

Regards
Nikunj