[PATCH v3 5/5] KVM: arm64: selftests: Test for setting ID register from usersapce

[Zenghui Yu]

On 2023/10/19 16:38, Eric Auger wrote:

>> +static const struct reg_ftr_bits ftr_id_aa64dfr0_el1[] = {
>> +	S_REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64DFR0_EL1, PMUVer, 0),
 >
> Strictly speaking this is not always safe to have a lower value. For
> instance: From Armv8.1, if FEAT_PMUv3 is implemented, the value 0b0001
> is not permitted. But I guess this consistency is to be taken into
> account by the user space. But may be wort a comment. Here and below
> 
> You may at least clarify what does mean 'safe'
 >
>> +	REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64DFR0_EL1, DebugVer, 0),

I've seen the following failure on Cortex A72 where
ID_AA64DFR0_EL1.DebugVer is 6.

# ./aarch64/set_id_regs
TAP version 13
1..79
ok 1 ID_AA64DFR0_EL1_PMUVer
==== Test Assertion Failure ====
   include/kvm_util_base.h:553: !ret
   pid=2288505 tid=2288505 errno=22 - Invalid argument
      1	0x0000000000402787: vcpu_set_reg at kvm_util_base.h:553 
(discriminator 6)
      2	 (inlined by) test_reg_set_success at set_id_regs.c:342 
(discriminator 6)
      3	 (inlined by) test_user_set_reg at set_id_regs.c:413 
(discriminator 6)
      4	0x0000000000401943: main at set_id_regs.c:475
      5	0x0000ffffbdd5d03b: ?? ??:0
      6	0x0000ffffbdd5d113: ?? ??:0
      7	0x0000000000401a2f: _start at ??:?
   KVM_SET_ONE_REG failed, rc: -1 errno: 22 (Invalid argument)