On Mon, Oct 7, 2013 at 4:07 PM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote: > > On 07/10/13 07:16, Gavin Guo wrote: > > On Sun, Oct 6, 2013 at 10:56 PM, Peter Maydell <peter.maydell@xxxxxxxxxx > > <mailto:peter.maydell@xxxxxxxxxx>> wrote: > > > > On 6 October 2013 23:03, Gavin Guo <gavin.guo@xxxxxxxxxxxxx > > <mailto:gavin.guo@xxxxxxxxxxxxx>> wrote: > > > Does it mean the currently qemu can't support A15 vcpu running on > > host A7? > > > > No, that's a kernel restriction. That is why the patch description > > reads: > > # This patch adds support for running Cortex-A7 guests on Cortex-A7 > > hosts. > > > > (What QEMU is currently missing is A7 support, so you can't ask it to > > run an A7 guest CPU.) > > > > -- PMM > > > > > > Thanks, I saw the checking in the kvm_vcpu_set_target(). I'm confused > > that what is the concern to run the same cpu type? Does it matter to run > > A15 on A7 or inverse? > > It does. MIDR registers are different. Cache size is different. It may > work, or it may not. And at the very least, you should present a > consistent view of the underlying system to the unsuspecting OS. > > M. > -- > Jazz is not dead. It just smells funny... > Hi Marc, How about the guest os with 4 x A15 vcpus run on a TC2 with 5 cores enabled (2 x A15 + 3 x A7). Does it mean that the 4 x A15 vcpus need to run on the 2 x A15 real cpus and can't be migrate to the 3 x A7? It seems that running 4 x A15 vcpus on the 2 x A15 and 2 x A7 core and leaving 1 A7 idle can take more computing power if all of the 4 x A15 guest os vcpus are full of loading. BTW, thanks for your reply, according to your reply I know the MIDR and cache size are different. Furthermore, I'd like to know if it is possible to make vcpu and real cpu in different type? If yes, I would like to study how to modify to make it work. Thanks, Gavin _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/cucslists/listinfo/kvmarm
