On Fri, 11 Oct 2019 11:50:11 +0100
Mark Rutland <mark.rutl...@arm.com> 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...
