On Tue, Dec 14, 2021 at 09:34:18AM +0000, Marc Zyngier wrote: > On Tue, 14 Dec 2021 00:41:01 +0000, > Qu Wenruo <quwenruo.btrfs@xxxxxxx> wrote: > > > > > > > > On 2021/12/14 00:49, Marc Zyngier wrote: > > > On Mon, 13 Dec 2021 16:06:14 +0000, > > > Peter Maydell <peter.maydell@xxxxxxxxxx> wrote: > > >> > > >> KVM on big.little setups is a kernel-level question really; I've > > >> cc'd the kvmarm list. > > > > > > Thanks Peter for throwing us under the big-little bus! ;-) > > > > > >> > > >> On Mon, 13 Dec 2021 at 15:02, Qu Wenruo <quwenruo.btrfs@xxxxxxx> wrote: > > >>> > > >>> > > >>> > > >>> On 2021/12/13 21:17, Michal Prívozník wrote: > > >>>> On 12/11/21 02:58, Qu Wenruo wrote: > > >>>>> Hi, > > >>>>> > > >>>>> Recently I got my libvirt setup on both RK3399 (RockPro64) and RPI CM4, > > >>>>> with upstream kernels. > > >>>>> > > >>>>> For RPI CM4 its mostly smooth sail, but on RK3399 due to its little.BIG > > >>>>> setup (core 0-3 are 4x A55 cores, and core 4-5 are 2x A72 cores), it > > >>>>> brings quite some troubles for VMs. > > >>>>> > > >>>>> In short, without proper cpuset to bind the VM to either all A72 cores > > >>>>> or all A55 cores, the VM will mostly fail to boot. > > > > > > s/A55/A53/. There were thankfully no A72+A55 ever produced (just the > > > though of it makes me sick). > > > > > >>>>> > > >>>>> Currently the working xml is: > > >>>>> > > >>>>> <vcpu placement='static' cpuset='4-5'>2</vcpu> > > >>>>> <cpu mode='host-passthrough' check='none'/> > > >>>>> > > >>>>> But even with vcpupin, pinning each vcpu to each physical core, VM will > > >>>>> mostly fail to start up due to vcpu initialization failed with -EINVAL. > > > > > > Disclaimer: I know nothing about libvirt (and no, I don't want to > > > know! ;-). > > > > > > However, for things to be reliable, you need to taskset the whole QEMU > > > process to the CPU type you intend to use. > > > > Yep, that's what I'm doing. > > Are you sure? The xml directive above seem to only apply to the vcpus, > and no other QEMU thread. For historical reasons this XML element is a bit misleadingly named. With the config <vcpu placement='static' cpuset='4-5'>2</vcpu> the 'cpuset' applies to the QEMU process as a whole - its vCPUs, I/O threads and any other emulator threads. There is a separate config for setting per-VCPU binding which was illustrated elsewhere in this thread. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
