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arm64/cpufeature: Validate hypervisor capabilities during CPU hotplug

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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

Suggested-by: Suzuki Poulose <suzuki.poulose@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1589248647-22925-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Anshuman Khandual 2020-05-12 07:27:27 +05:30 committed by Will Deacon
parent eeb2d87ece
commit c73433fc63
4 changed files with 56 additions and 1 deletions
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18
arch/arm64/include/asm/cpufeature.h
View file

@ -752,6 +752,24 @@ 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

2
arch/arm64/include/asm/kvm_mmu.h
View file

@ -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);
}
/*

32
arch/arm64/kernel/cpufeature.c
View file

@ -2315,6 +2315,35 @@ static void verify_sve_features(void)
/* Add checks on other ZCR bits here if necessary */
}
static void verify_hyp_capabilities(void)
{
u64 safe_mmfr1, mmfr0, mmfr1;
int parange, ipa_max;
unsigned int safe_vmid_bits, vmid_bits;
if (!IS_ENABLED(CONFIG_KVM) || !IS_ENABLED(CONFIG_KVM_ARM_HOST))
return;
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();
}
}
/*
* Run through the enabled system capabilities and enable() it on this CPU.
@ -2340,6 +2369,9 @@ 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)

5
arch/arm64/kvm/reset.c
View file

@ -332,6 +332,11 @@ 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;