On Fri, Feb 22, 2019 at 03:40:50PM +0000, Marc Zyngier wrote: [...] > > > The interrupt affinity is either defined by the distributor > > > configuration (SPIs) or the ITS configuration (LPIs). > > > > Given to the up example, I am struggling to understand how you can set > > the interrupt affinity for virtio device. > > > > Do you set the physical interrupt affinity to CPU0/1 in host OS and > > forward it to guest OS? Or set interrupt affinity in guest OS (I > > tried on Juno board to set irq affinity in guest OS from > > '/proc/irq/xxx/smp_affinity' but failed)? Or this is accomplished by > > user space tool (lkvm or qemu)? > > virtio interrupts are purely virtual, and the host plays no part in > their routing (nor does userspace). As for their affinity, that > depends on the virtio driver. Some virtio devices allow their affinity > to be changed, some don't. Here, this is a virtio-net device, which is > perfectly happy to see its queue interrupts moved to a different vcpu. > > I tend to run irqbalance in my guests so that it actually exercises > the affinity setting in the background. > > > Sorry if I am asking a stupid question :) > > It's not stupid. You're simply confusing multiple independent layers. Thanks a lot for explaination, Marc. Thanks, Leo Yan _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
