Re: Relax CPU features sanity checking on heterogeneous architectures
From: Sai Prakash Ranjan
Date: Fri Oct 18 2019 - 06:18:55 EST
On 2019-10-18 01:30, Stephen Boyd wrote:
Quoting Sai Prakash Ranjan (2019-10-11 06:40:13)
On 2019-10-11 19:04, Marc Zyngier wrote:
> On Fri, 11 Oct 2019 18:47:39 +0530
> Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx> wrote:
>
>> Hi Mark,
>>
>> Thanks a lot for the detailed explanations, I did have a look at all
>> the variations before posting this.
>>
>> On 2019-10-11 16:20, Mark Rutland 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 is based on Cortex-A55(little cores) and Cortex-A76(big cores).
>> I'm afraid I cannot give details about SC7180 yet.
>>
>> >> 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 not support KVM.
>
> Mainline does. You don't get to pick and choose what is supported or
> not.
>
Ok thats good.
I want KVM on sc7180. How do I get it? Is something going to not work?
I meant KVM is not supported for downstream android case where we do not
have kernel booting from EL2.
And obviously I am wrong because SC7180 is not for android, so my bad.
I think Mark R's question about handling KVM variation was for Marc Z
not me :p
As for something not going to work, as Mark said this warning does
indicate that 32 bit EL1 guests won't
be able to run on big CPU cores.
- Sai