On Mon, Mar 08, 2021 at 02:42:00PM +0000, Marc Zyngier wrote:
> On Fri, 05 Mar 2021 14:36:09 +0000,
> Anshuman Khandual <anshuman.khandual@xxxxxxx> wrote:
> > - switch (cpuid_feature_extract_unsigned_field(mmfr0, tgran_2)) {
> > - default:
> > - case 1:
> > + tgran_2 = cpuid_feature_extract_unsigned_field(mmfr0, tgran_2_shift);
> > + if (tgran_2 == ID_AA64MMFR0_TGRAN_2_SUPPORTED_NONE) {
> > kvm_err("PAGE_SIZE not supported at Stage-2, giving up\n");
> > return -EINVAL;
> > - case 0:
> > + } else if (tgran_2 == ID_AA64MMFR0_TGRAN_2_SUPPORTED_DEFAULT) {
> > kvm_debug("PAGE_SIZE supported at Stage-2 (default)\n");
> > - break;
> > - case 2:
> > + } else if (tgran_2 >= ID_AA64MMFR0_TGRAN_2_SUPPORTED_MIN &&
> > + tgran_2 <= ID_AA64MMFR0_TGRAN_2_SUPPORTED_MAX) {
> > kvm_debug("PAGE_SIZE supported at Stage-2 (advertised)\n");
> > - break;
> > + } else {
> > + kvm_err("Unsupported value, giving up\n");
> > + return -EINVAL;
>
> nit: this doesn't say *what* value is unsupported, and I really
> preferred the switch-case version, such as this:
>
> diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
> index 1f22b36a0eff..d267e4b1aec6 100644
> --- a/arch/arm64/kvm/reset.c
> +++ b/arch/arm64/kvm/reset.c
> @@ -312,15 +312,18 @@ int kvm_set_ipa_limit(void)
>
> switch (cpuid_feature_extract_unsigned_field(mmfr0, tgran_2)) {
> default:
> - case 1:
> + case ID_AA64MMFR0_TGRAN_2_SUPPORTED_NONE:
> kvm_err("PAGE_SIZE not supported at Stage-2, giving up\n");
> return -EINVAL;
> - case 0:
> + case ID_AA64MMFR0_TGRAN_2_SUPPORTED_DEFAULT:
> kvm_debug("PAGE_SIZE supported at Stage-2 (default)\n");
> break;
> - case 2:
> + case ID_AA64MMFR0_TGRAN_2_SUPPORTED_MIN ... ID_AA64MMFR0_TGRAN_2_SUPPORTED_MAX:
> kvm_debug("PAGE_SIZE supported at Stage-2 (advertised)\n");
> break;
> + default:
> + kvm_err("Unsupported value for TGRAN_2, giving up\n");
> + return -EINVAL;
> }
>
> kvm_ipa_limit = id_aa64mmfr0_parange_to_phys_shift(parange);
>
>
> Otherwise:
>
> Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
Anshuman -- please can you spin a v2 with the switch syntax as suggested
above by Marc?
Will
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