On Fri, 11 Oct 2019 11:50:11 +0100 Mark Rutland <mark.rutland@xxxxxxx> wrote: > Hi, > > On Fri, Oct 11, 2019 at 11:19:00AM +0530, Sai Prakash Ranjan wrote: > > On latest QCOM SoCs like SM8150 and SC7180 with big.LITTLE arch, below > > warnings are observed during bootup of big cpu cores. > > For reference, which CPUs are in those SoCs? > > > SM8150: > > > > [ 0.271177] CPU features: SANITY CHECK: Unexpected variation in > > SYS_ID_AA64PFR0_EL1. Boot CPU: 0x00000011112222, CPU4: 0x00000011111112 > > The differing fields are EL3, EL2, and EL1: the boot CPU supports > AArch64 and AArch32 at those exception levels, while the secondary only > supports AArch64. > > Do we handle this variation in KVM? We do, at least at vcpu creation time (see kvm_reset_vcpu). But if one of the !AArch32 CPU comes in late in the game (after we've started a guest), all bets are off (we'll schedule the 32bit guest on that CPU, enter the guest, immediately take an Illegal Exception Return, and return to userspace with KVM_EXIT_FAIL_ENTRY). Not sure we could do better, given the HW. My preference would be to fail these CPUs if they aren't present at boot time. M. -- Jazz is not dead. It just smells funny...
