* [PATCH V3] arm64/cpufeature: Validate hypervisor capabilities during CPU hotplug
@ 2020-05-12 1:57 Anshuman Khandual
2020-05-20 17:54 ` Will Deacon
0 siblings, 1 reply; 3+ messages in thread
From: Anshuman Khandual @ 2020-05-12 1:57 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Anshuman Khandual, Catalin Marinas, Will Deacon, Marc Zyngier,
Mark Rutland, James Morse, Suzuki K Poulose, kvmarm,
linux-kernel
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 <anshuman.khandual@arm.com>
---
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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH V3] arm64/cpufeature: Validate hypervisor capabilities during CPU hotplug
2020-05-12 1:57 [PATCH V3] arm64/cpufeature: Validate hypervisor capabilities during CPU hotplug Anshuman Khandual
@ 2020-05-20 17:54 ` Will Deacon
2020-05-21 0:48 ` Anshuman Khandual
0 siblings, 1 reply; 3+ messages in thread
From: Will Deacon @ 2020-05-20 17:54 UTC (permalink / raw)
To: Anshuman Khandual, linux-arm-kernel
Cc: catalin.marinas, Will Deacon, linux-kernel, kvmarm, Marc Zyngier
On Tue, 12 May 2020 07:27:27 +0530, Anshuman Khandual wrote:
> 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
Applied to arm64 (for-next/cpufeature), thanks!
[1/1] arm64/cpufeature: Validate hypervisor capabilities during CPU hotplug
https://git.kernel.org/arm64/c/c73433fc630c
But please note that I made some changes to verify_hyp_capabilities() so
that it's (a) static and (b) uses IS_ENABLED to avoid the dummy function
definition. I also extended the IS_ENABLED_check so that it doesn't
conflict with the KVM kconfig changes from Fuad. Please shout if you think
I'm still missing something.
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH V3] arm64/cpufeature: Validate hypervisor capabilities during CPU hotplug
2020-05-20 17:54 ` Will Deacon
@ 2020-05-21 0:48 ` Anshuman Khandual
0 siblings, 0 replies; 3+ messages in thread
From: Anshuman Khandual @ 2020-05-21 0:48 UTC (permalink / raw)
To: Will Deacon, linux-arm-kernel
Cc: catalin.marinas, linux-kernel, kvmarm, Marc Zyngier
On 05/20/2020 11:24 PM, Will Deacon wrote:
> On Tue, 12 May 2020 07:27:27 +0530, Anshuman Khandual wrote:
>> 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
>
> Applied to arm64 (for-next/cpufeature), thanks!
>
> [1/1] arm64/cpufeature: Validate hypervisor capabilities during CPU hotplug
> https://git.kernel.org/arm64/c/c73433fc630c
>
> But please note that I made some changes to verify_hyp_capabilities() so
> that it's (a) static and (b) uses IS_ENABLED to avoid the dummy function
> definition. I also extended the IS_ENABLED_check so that it doesn't
> conflict with the KVM kconfig changes from Fuad. Please shout if you think
> I'm still missing something.
Normally I would have expected get_kvm_ipa_limit() to be unavailable without
CONFIG_KVM_ARM_HOST, causing a build failure. But it does compile correctly.
Probably the compiler does not really look for get_kvm_ipa_limit() definition
after an early check and bailout on !IS_ENABLED(CONFIG_KVM_ARM_HOST).
Nonetheless, changes looks good. Thank you.
- Anshuman
^ permalink raw reply [flat|nested] 3+ messages in thread
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