Hi Yasutaka, On Thu, Mar 02, 2017 at 09:57:50AM -0500, Yasutaka Tanaka wrote: > Hello KVM/ARM community, > > I am now trying to execute KVM on Raspberry Pi 3 Model B (RPI3). > Does anyone know whether KVM/ARM can run with 32-bit mode on ARM Cortex A53? Theoretically, it should. > > The CPU of RPI3 is ARM Cortex A53 which can be executed in both 32-bit and > 64-bit mode. I've managed to display /dev/kvm on 64-bit mode execution > (i.e. with a 64-bit linux kernel) on RPI3, but I failed to do so in 32-bit > mode. > > In 32-bit mode, an KVM error messages says CPU not supported. I guess the > reason for the error message is KVM_ARM_TARGET_CORTEX_A53 is only returned > in /arch/arm64/kvm/guest.c not under/arch/arm/kvm/guest.c. > > So I'm wondering whether it's possible or not. It should be. You may just have to add the minimal missing definitions for a 32-bit A53 CPU support. > What I'd like to do is to > compare the execution speed of KVM between 32-bit and 64-bit mode. The > second plan is to compare between KVMs of 32-bit RPI2 and 64-bit RPI3 (I > have both), but since RPI2 spec is a little low and I'm worried that some > numeric comparisons become unfair. I would be careful here, since the RPI3 doesn't have the GIC and you'll end up going to user space a lot for interrupt handling. Especially look out for SMP workloads in the VM which may generate a lot of IPIs which are really going to suffer from having to go to userspace on the host. > > (I was also notified by an KVM/ARM expert that since RPI doesn't have a GIC > and I need to apply some patches) Yes, you need the "Support userspace irqchip with arch timers" series and corresponding QEMU patches: http://www.spinics.net/lists/kvm/msg144685.html Good luck. -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
