On Tue, May 12, 2020 at 07:43:26AM +0530, Anshuman Khandual wrote:
> This replaces multiple open encoding (0x7) with ID_AA64MMFR0_PARANGE_MASK
> thus cleaning the clutter. It modifies an existing ID_AA64MMFR0 helper and
> introduces a new one i.e id_aa64mmfr0_iparange() and id_aa64mmfr0_parange()
> respectively.
>
> Cc: Catalin Marinas <catalin.mari...@arm.com>
> Cc: Will Deacon <w...@kernel.org>
> Cc: Marc Zyngier <m...@kernel.org>
> Cc: James Morse <james.mo...@arm.com>
> Cc: linux-arm-ker...@lists.infradead.org
> Cc: linux-ker...@vger.kernel.org
> Cc: kvmarm@lists.cs.columbia.edu
>
> Signed-off-by: Anshuman Khandual <anshuman.khand...@arm.com>
> ---
> This applies after (https://patchwork.kernel.org/patch/11541893/).
>
> arch/arm64/include/asm/cpufeature.h | 11 ++++++++++-
> arch/arm64/kernel/cpufeature.c | 5 ++---
> arch/arm64/kvm/reset.c | 9 +++++----
> 3 files changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm64/include/asm/cpufeature.h
> b/arch/arm64/include/asm/cpufeature.h
> index 1291ad5a9ccb..320cfc5b6025 100644
> --- a/arch/arm64/include/asm/cpufeature.h
> +++ b/arch/arm64/include/asm/cpufeature.h
> @@ -706,8 +706,17 @@ void arm64_set_ssbd_mitigation(bool state);
>
> extern int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt);
>
> -static inline u32 id_aa64mmfr0_parange_to_phys_shift(int parange)
> +#define ID_AA64MMFR0_PARANGE_MASK 0x7
We already have ID_AA64MMFR0_PARANGE_SHIFT in <asm/sysreg.h>, so if we
need this it should live there too.
The ARM ARM tells me ID_AA64MMFR0_EL1.PARange is bits 3:0, so this
should be 0xf.
Given it's a standard 4-bit field, do we even need this? We have helpers
that assume 4 bits for standard fields, e.g.
cpuid_feature_extract_unsigned_field().
> +
> +static inline u32 id_aa64mmfr0_parange(u64 mmfr0)
> {
> + return mmfr0 & ID_AA64MMFR0_PARANGE_MASK;
> +}
return cpuid_feature_extract_unsigned_field(mmfr0,
ID_AA64MMFR0_PARANGE_SHIFT);
> +
> +static inline u32 id_aa64mmfr0_iparange(u64 mmfr0)
> +{
> + int parange = id_aa64mmfr0_parange(mmfr0);
> +
> switch (parange) {
> case 0: return 32;
> case 1: return 36;
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 30917fe7942a..2c62f7c64a3c 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -2185,7 +2185,7 @@ static void verify_sve_features(void)
> void verify_hyp_capabilities(void)
> {
> u64 safe_mmfr1, mmfr0, mmfr1;
> - int parange, ipa_max;
> + int ipa_max;
> unsigned int safe_vmid_bits, vmid_bits;
>
> safe_mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
> @@ -2201,8 +2201,7 @@ void verify_hyp_capabilities(void)
> }
>
> /* Verify IPA range */
> - parange = mmfr0 & 0x7;
> - ipa_max = id_aa64mmfr0_parange_to_phys_shift(parange);
> + ipa_max = id_aa64mmfr0_iparange(mmfr0);
Why drop id_aa64mmfr0_parange_to_phys_shift()?
> if (ipa_max < get_kvm_ipa_limit()) {
> pr_crit("CPU%d: IPA range mismatch\n", smp_processor_id());
> cpu_die_early();
> diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
> index 841b492ff334..2e4da75d79ea 100644
> --- a/arch/arm64/kvm/reset.c
> +++ b/arch/arm64/kvm/reset.c
> @@ -347,10 +347,10 @@ u32 get_kvm_ipa_limit(void)
>
> void kvm_set_ipa_limit(void)
> {
> - unsigned int ipa_max, pa_max, va_max, parange;
> + unsigned int ipa_max, pa_max, va_max;
>
> - parange = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1) & 0x7;
> - pa_max = id_aa64mmfr0_parange_to_phys_shift(parange);
> + pa_max = id_aa64mmfr0_iparange(read_sanitised_ftr_reg
> + (SYS_ID_AA64MMFR0_EL1));
Weird style here. the '(' should be kept next to the function name.
>
> /* Clamp the IPA limit to the PA size supported by the kernel */
> ipa_max = (pa_max > PHYS_MASK_SHIFT) ? PHYS_MASK_SHIFT : pa_max;
> @@ -411,7 +411,8 @@ int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long
> type)
> phys_shift = KVM_PHYS_SHIFT;
> }
>
> - parange = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1) & 7;
> + parange = id_aa64mmfr0_parange(read_sanitised_ftr_reg
> + (SYS_ID_AA64MMFR0_EL1));
Can't we add a system_ipa_range() helper, and avoid more boilerplate in
each of these?
e.g.
int system_ipa_range(void)
{
u64 mmfr0;
int parange;
mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
parange = cpuid_feature_extract_unsigned_field(mmfr0,
ID_AA64MMFR0_PARANGE_SHIFT);
return parange;
}
... we do similar for the system_supports_xxx() helpers.
Thanks,
Mark.
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