On 2013-08-14 16:35, Peter Maydell wrote:
> On 14 August 2013 16:23, Marc Zyngier <marc.zyngier@xxxxxxx> wrote:
>> On 2013-08-14 15:22, Anup Patel wrote:
>>> It seems a bit unnatural to have cache cleaning is user-space. I am
>>> sure
>>> other architectures don't have such cache cleaning in user-space
>>> for
>>> KVM.
>>
>> Well, we have it on AArch64. Why would we blindly nuke the whole
>> cache
>> if we can do the right thing, efficiently, on the right range?
>
> When exactly would userspace have to care about the cache?
Only for the initial payload, I'd expect. Unless I've missed something
more crucial?
> This patch isn't exactly clear about the circumstances. I
> think you'd need a really strong reason for not dealing with
> this in the kernel -- in general userspace KVM tools don't
> otherwise have to deal with cache maintenance at all.
I believe we *could* do it in the kernel, just at the expense of a lot
more CPU cycles.
A possible alternative would be to use HCR.DC, but I need to have a
look and see what it breaks...
M.
--
Fast, cheap, reliable. Pick two.
_______________________________________________
kvmarm mailing list
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
