Hi Marc,
On 3/16/21 1:22 PM, Marc Zyngier wrote:
> Hi Vladimir,
>
> On Tue, 16 Mar 2021 11:25:00 +0000,
> Vladimir Murzin <vladimir.murzin@xxxxxxx> wrote:
>>
>> Commit 78869f0f0552 ("arm64: Extract parts of el2_setup into a macro")
>> reorganized el2 setup in such way that virtual cpu id registers set
>> only in nVHE, yet they used (and need) to be set irrespective VHE
>> support. Lack of setup causes 32-bit guest stop booting due to MIDR
>> stay undefined.
>
> Surely this affects 64bit guests as well, doesn't it? I guess the
> 32bit code tries to infer stuff such as the architecture revision from
> MIDR and falls over, and that the 64bit Linux code has less baggage?
Correct, that affects all guests, yet 32-bit tries to lookup processor type
so it is how it became visible to me
>
>>
>> Fixes: 78869f0f0552 ("arm64: Extract parts of el2_setup into a macro")
>> Signed-off-by: Vladimir Murzin <vladimir.murzin@xxxxxxx>
>> ---
>>
>> There is no upstream fix since issue went away due to code there has
>> been reworked in 5.12: nVHE comes first, so virtual cpu id register
>> are always set.
>>
>> Maintainers, please, Ack.
>>
>> arch/arm64/include/asm/el2_setup.h | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
>> index f988e94cdf9e..db87daca6b8c 100644
>> --- a/arch/arm64/include/asm/el2_setup.h
>> +++ b/arch/arm64/include/asm/el2_setup.h
>> @@ -113,7 +113,7 @@
>> .endm
>>
>> /* Virtual CPU ID registers */
>> -.macro __init_el2_nvhe_idregs
>> +.macro __init_el2_idregs
>> mrs x0, midr_el1
>> mrs x1, mpidr_el1
>> msr vpidr_el2, x0
>> @@ -165,6 +165,7 @@
>> __init_el2_stage2
>> __init_el2_gicv3
>> __init_el2_hstr
>> + __init_el2_idregs
>>
>> /*
>> * When VHE is not in use, early init of EL2 needs to be done here.
>> @@ -173,7 +174,6 @@
>> * will be done via the _EL1 system register aliases in __cpu_setup.
>> */
>> .ifeqs "\mode", "nvhe"
>> - __init_el2_nvhe_idregs
>> __init_el2_nvhe_cptr
>> __init_el2_nvhe_sve
>> __init_el2_nvhe_prepare_eret
>
> The couple of VHE systems I have around don't suffer from this issue,
> but it looks like I can trigger it on the FVP model (probably because
> the model is nasty enough to not have VPIDR_EL2 default to anything
> sensible!).
Well firmware could easily hide the issue if it set registers for us ;)
>
> Anyway, good catch. If you can respin it to drop the reference to
> 32bit guests, I'll happily ack it!
Thanks for prompt review! I'll re-spin it shortly.
Vladimir
>
> Thanks,
>
> M.
>
