[lkml]   [2017]   [Sep]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 3/3] KVM: SVM: Add irqchip_split() checks before enabling AVIC
On 12/09/2017 15:17, Radim Krčmář wrote:
>>> Yeah, hacking TMR to get the VM exit could result in future bugs.
>>> We have to push split irqchip as the deafult in userspaces with this
>>> change.
>> Actually, I'm not quite sure about the advantages/disadvantages with split
>> irqchip, and how it would affect other cases, and why it was not used as
>> default currently.
> The main advantage of split irqchip is that we're moving code out of the
> kernel, and QEMU's irqchip currently has more features too.
> I think it is not the default as the support for split irqchip is recent
> (v4.3) and has lower performance, so it is only used in cases that need
> the extra features.

One other difference is that in-kernel PIT is not supported with
split-irqchip, and the QEMU PIT lacks support for reinjecting lost
ticks. But this should only be needed for very old guests at this point.


 \ /
  Last update: 2017-09-12 16:23    [W:0.101 / U:0.060 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site