[PATCH V3] arm64/cpufeature: Validate hypervisor capabilities during CPU hotplug
From: Anshuman Khandual <hidden>
Date: 2020-05-12 01:58:08
This validates hypervisor capabilities like VMID width, IPA range for any hot plug CPU against system finalized values. KVM's view of the IPA space is used while allowing a given CPU to come up. While here, it factors out get_vmid_bits() for general use. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Marc Zyngier <maz@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: kvmarm@lists.cs.columbia.edu Cc: linux-kernel@vger.kernel.org Reviewed-by: Marc Zyngier <maz@kernel.org> Suggested-by: Suzuki Poulose <suzuki.poulose@arm.com> Signed-off-by: Anshuman Khandual <redacted> --- Changes in V3: - Dropped "#ifdef CONFIG_KVM_ARM_HOST" per Marc - Dropped ID_AA64MMFR0_PARANGE_MASK (for now) - Updated the commit message per Marc Changes in V2: (https://patchwork.kernel.org/patch/11535359/) - Added is_hyp_mode_available() check per Marc - Moved verify_kvm_capabilities() into cpufeature.c per Marc - Added helper get_kvm_ipa_limit() to fetch kvm_ipa_limit per Marc - Renamed kvm as hyp including the commit message per Marc Changes in V1: (https://patchwork.kernel.org/patch/11532565/) arch/arm64/include/asm/cpufeature.h | 18 ++++++++++++++++ arch/arm64/include/asm/kvm_mmu.h | 2 +- arch/arm64/kernel/cpufeature.c | 33 +++++++++++++++++++++++++++++ arch/arm64/kvm/reset.c | 5 +++++ 4 files changed, 57 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index afe08251ff95..1291ad5a9ccb 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h@@ -745,6 +745,24 @@ static inline bool cpu_has_hw_af(void) extern bool cpu_has_amu_feat(int cpu); #endif +static inline unsigned int get_vmid_bits(u64 mmfr1) +{ + int vmid_bits; + + vmid_bits = cpuid_feature_extract_unsigned_field(mmfr1, + ID_AA64MMFR1_VMIDBITS_SHIFT); + if (vmid_bits == ID_AA64MMFR1_VMIDBITS_16) + return 16; + + /* + * Return the default here even if any reserved + * value is fetched from the system register. + */ + return 8; +} + +u32 get_kvm_ipa_limit(void); + #endif /* __ASSEMBLY__ */ #endif
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 30b0e8d6b895..a7137e144b97 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h@@ -416,7 +416,7 @@ static inline unsigned int kvm_get_vmid_bits(void) { int reg = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); - return (cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR1_VMIDBITS_SHIFT) == 2) ? 16 : 8; + return get_vmid_bits(reg); } /*
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 9fac745aa7bb..30917fe7942a 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c@@ -2181,6 +2181,36 @@ static void verify_sve_features(void) /* Add checks on other ZCR bits here if necessary */ } +#ifdef CONFIG_KVM_ARM_HOST +void verify_hyp_capabilities(void) +{ + u64 safe_mmfr1, mmfr0, mmfr1; + int parange, ipa_max; + unsigned int safe_vmid_bits, vmid_bits; + + safe_mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); + mmfr0 = read_cpuid(ID_AA64MMFR0_EL1); + mmfr1 = read_cpuid(ID_AA64MMFR1_EL1); + + /* Verify VMID bits */ + safe_vmid_bits = get_vmid_bits(safe_mmfr1); + vmid_bits = get_vmid_bits(mmfr1); + if (vmid_bits < safe_vmid_bits) { + pr_crit("CPU%d: VMID width mismatch\n", smp_processor_id()); + cpu_die_early(); + } + + /* Verify IPA range */ + parange = mmfr0 & 0x7; + ipa_max = id_aa64mmfr0_parange_to_phys_shift(parange); + if (ipa_max < get_kvm_ipa_limit()) { + pr_crit("CPU%d: IPA range mismatch\n", smp_processor_id()); + cpu_die_early(); + } +} +#else /* !CONFIG_KVM_ARM_HOST */ +static inline void verify_hyp_capabilities(void) { } +#endif /* CONFIG_KVM_ARM_HOST */ /* * Run through the enabled system capabilities and enable() it on this CPU.
@@ -2206,6 +2236,9 @@ static void verify_local_cpu_capabilities(void) if (system_supports_sve()) verify_sve_features(); + + if (is_hyp_mode_available()) + verify_hyp_capabilities(); } void check_local_cpu_capabilities(void)
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 30b7ea680f66..841b492ff334 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c@@ -340,6 +340,11 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) return ret; } +u32 get_kvm_ipa_limit(void) +{ + return kvm_ipa_limit; +} + void kvm_set_ipa_limit(void) { unsigned int ipa_max, pa_max, va_max, parange;
--
2.20.1
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