[PATCH v1] KVM: arm64: selftests: Handle feature fields with nonzero minimum value correctly

[Zenghui Yu]

Hi Jing,

On 2024/1/10 0:56, Jing Zhang wrote:
> There are some feature fields with nonzero minimum valid value. Make
> sure get_safe_value() won't return invalid field values for them.
> Also fix a bug that wrongly uses the feature bits type as the feature
> bits sign causing all fields as signed in the get_safe_value() and
> get_invalid_value().
> 
> Fixes: 54a9ea73527d ("KVM: arm64: selftests: Test for setting ID register from usersapce")
> Reported-by: Zenghui Yu <yuzenghui at huawei.com>
> Reported-by: Itaru Kitayama <itaru.kitayama at linux.dev>
> Signed-off-by: Jing Zhang <jingzhangos at google.com>
> ---
>  .../selftests/kvm/aarch64/set_id_regs.c       | 20 +++++++++++++++----
>  1 file changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/aarch64/set_id_regs.c b/tools/testing/selftests/kvm/aarch64/set_id_regs.c
> index bac05210b539..f17454dc6d9e 100644
> --- a/tools/testing/selftests/kvm/aarch64/set_id_regs.c
> +++ b/tools/testing/selftests/kvm/aarch64/set_id_regs.c
> @@ -224,13 +224,20 @@ uint64_t get_safe_value(const struct reg_ftr_bits *ftr_bits, uint64_t ftr)
>  {
>  	uint64_t ftr_max = GENMASK_ULL(ARM64_FEATURE_FIELD_BITS - 1, 0);
>   
> -	if (ftr_bits->type == FTR_UNSIGNED) {
> +	if (ftr_bits->sign == FTR_UNSIGNED) {
>  		switch (ftr_bits->type) {
>  		case FTR_EXACT:
>  			ftr = ftr_bits->safe_val;
>  			break;
>  		case FTR_LOWER_SAFE:
> -			if (ftr > 0)
> +			uint64_t min_safe = 0;
> +
> +			if (!strcmp(ftr_bits->name, "ID_AA64DFR0_EL1_DebugVer"))
> +				min_safe = ID_AA64DFR0_EL1_DebugVer_IMP;
> +			else if (!strcmp(ftr_bits->name, "ID_DFR0_EL1_CopDbg"))
> +				min_safe = ID_DFR0_EL1_CopDbg_Armv8;
> +
> +			if (ftr > min_safe)

As I mentioned in my previous reply, there is a compilation error with
gcc-10.3.1.

| aarch64/set_id_regs.c: In function 'get_safe_value':
| aarch64/set_id_regs.c:233:4: error: a label can only be part of a 
statement and a declaration is not a statement
|   233 |    uint64_t min_safe = 0;
|       |    ^~~~~~~~
| aarch64/set_id_regs.c:262:4: error: a label can only be part of a 
statement and a declaration is not a statement
|   262 |    uint64_t min_safe = 0;
|       |    ^~~~~~~~

Please fix it.

Zenghui