On 12/09/2017 15:17, Radim KrÄmÃÅ wrote:
The main advantage of split irqchip is that we're moving code out of theYeah, hacking TMR to get the VM exit could result in future bugs.Actually, I'm not quite sure about the advantages/disadvantages with split
We have to push split irqchip as the deafult in userspaces with this
change.
irqchip, and how it would affect other cases, and why it was not used as
default currently.
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.
Paolo