Re: [PATCH] KVM: arm/arm64: Set ICH_HCR_EN in guest anyway when using gicv4

[Marc Zyngier]

On 13/03/2019 15:59, Shameerali Kolothum Thodi wrote:

Hi Shameer,

>> Can you please give the following patch a go? I can't test it, but hopefully
>> you can.
> 
> Thanks for your quick response. I just did a quick test on one of our platforms
> with VHE+GICv4 and it seems to fix the performance issue we were seeing
> when GICv4 is enabled.
> 
> Test setup:
> 
> Host connected to a PC over a 10G port.
> Launch Guest with an assigned vf dev.
> Run iperf from Guest,
> 
> 5.0 kernel:
> [ ID]  Interval       Transfer     Bandwidth
> [  3]  0.0-10.0 sec  1.30 GBytes  1.12 Gbits/sec
> 
> +Patch:
> 
> [ ID] 	Interval       Transfer     Bandwidth
> [  3]  0.0-10.0 sec  10.9 GBytes  9.39 Gbits/sec

Ah, that looks much better! I'll try to write it properly, as I think
what we have today is slightly bizarre (we write ICH_HCR_EL2 from too
many paths, and I need to remember how the whole thing works).

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...