diff options
| author | Ryan Roberts <ryan.roberts@arm.com> | 2023-11-27 12:17:30 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2023-11-27 16:03:50 +0100 |
| commit | b1366d21daaebb8e474e4169c5e557fbb37bfdc0 (patch) | |
| tree | 44de9e75a1196c7d0bc85f7536ad1b49a0cc1384 /arch | |
| parent | arm64/mm: Add FEAT_LPA2 specific ID_AA64MMFR0.TGRAN[2] (diff) | |
| download | linux-b1366d21daaebb8e474e4169c5e557fbb37bfdc0.tar.xz linux-b1366d21daaebb8e474e4169c5e557fbb37bfdc0.zip | |
arm64: Add ARM64_HAS_LPA2 CPU capability
Expose FEAT_LPA2 as a capability so that we can take advantage of
alternatives patching in the hypervisor.
Although FEAT_LPA2 presence is advertised separately for stage1 and
stage2, the expectation is that in practice both stages will either
support or not support it. Therefore, we combine both into a single
capability, allowing us to simplify the implementation. KVM requires
support in both stages in order to use LPA2 since the same library is
used for hyp stage 1 and guest stage 2 pgtables.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231127111737.1897081-6-ryan.roberts@arm.com
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 5 | ||||
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 39 | ||||
| -rw-r--r-- | arch/arm64/tools/cpucaps | 1 |
3 files changed, 45 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index f6d416fe49b0..acf109581ac0 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -819,6 +819,11 @@ static inline bool system_supports_tlb_range(void) return alternative_has_cap_unlikely(ARM64_HAS_TLB_RANGE); } +static inline bool system_supports_lpa2(void) +{ + return cpus_have_final_cap(ARM64_HAS_LPA2); +} + int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt); bool try_emulate_mrs(struct pt_regs *regs, u32 isn); diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 646591c67e7a..7900ba7e157e 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1768,6 +1768,39 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, return !meltdown_safe; } +#if defined(ID_AA64MMFR0_EL1_TGRAN_LPA2) && defined(ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_LPA2) +static bool has_lpa2_at_stage1(u64 mmfr0) +{ + unsigned int tgran; + + tgran = cpuid_feature_extract_unsigned_field(mmfr0, + ID_AA64MMFR0_EL1_TGRAN_SHIFT); + return tgran == ID_AA64MMFR0_EL1_TGRAN_LPA2; +} + +static bool has_lpa2_at_stage2(u64 mmfr0) +{ + unsigned int tgran; + + tgran = cpuid_feature_extract_unsigned_field(mmfr0, + ID_AA64MMFR0_EL1_TGRAN_2_SHIFT); + return tgran == ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_LPA2; +} + +static bool has_lpa2(const struct arm64_cpu_capabilities *entry, int scope) +{ + u64 mmfr0; + + mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1); + return has_lpa2_at_stage1(mmfr0) && has_lpa2_at_stage2(mmfr0); +} +#else +static bool has_lpa2(const struct arm64_cpu_capabilities *entry, int scope) +{ + return false; +} +#endif + #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 #define KPTI_NG_TEMP_VA (-(1UL << PMD_SHIFT)) @@ -2731,6 +2764,12 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .matches = has_cpuid_feature, ARM64_CPUID_FIELDS(ID_AA64MMFR2_EL1, EVT, IMP) }, + { + .desc = "52-bit Virtual Addressing for KVM (LPA2)", + .capability = ARM64_HAS_LPA2, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .matches = has_lpa2, + }, {}, }; diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index b98c38288a9d..919eceb0b3da 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -37,6 +37,7 @@ HAS_GIC_PRIO_MASKING HAS_GIC_PRIO_RELAXED_SYNC HAS_HCX HAS_LDAPR +HAS_LPA2 HAS_LSE_ATOMICS HAS_MOPS HAS_NESTED_VIRT |