linux-kernel - [PATCH V2] arm64/cpufeature: Drop open encodings while extracting parange

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Message-Id: <1589360614-1164-1-git-send-email-anshuman.khandual@arm.com>
Date:   Wed, 13 May 2020 14:33:34 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     mark.rutland@....com,
        Anshuman Khandual <anshuman.khandual@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        kvmarm@...ts.cs.columbia.edu, linux-kernel@...r.kernel.org
Subject: [PATCH V2] arm64/cpufeature: Drop open encodings while extracting parange

Currently there are multiple instances of parange feature width mask open
encodings while fetching it's value. Even the width mask value (0x7) itself
is not accurate. It should be (0xf) per ID_AA64MMFR0_EL1.PARange[3:0] as in
ARM ARM (0487F.a). Replace them with cpuid_feature_extract_unsigned_field()
which can extract given standard feature (4 bits width i.e 0xf mask) field.

Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Marc Zyngier <maz@...nel.org>
Cc: James Morse <james.morse@....com>
Cc: kvmarm@...ts.cs.columbia.edu
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org

Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
---
Changes in V2:

- Used cpuid_feature_extract_unsigned_field() per Mark

Changes in V1: (https://patchwork.kernel.org/patch/11541913/)

 arch/arm64/kernel/cpufeature.c |  3 ++-
 arch/arm64/kvm/reset.c         | 11 ++++++++---
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 30917fe7942a..958a96947c2c 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2201,7 +2201,8 @@ void verify_hyp_capabilities(void)
 	}
 
 	/* Verify IPA range */
-	parange = mmfr0 & 0x7;
+	parange = cpuid_feature_extract_unsigned_field(mmfr0,
+				ID_AA64MMFR0_PARANGE_SHIFT);
 	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());
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 841b492ff334..bd9f66a81e1e 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -348,8 +348,11 @@ u32 get_kvm_ipa_limit(void)
 void kvm_set_ipa_limit(void)
 {
 	unsigned int ipa_max, pa_max, va_max, parange;
+	u64 mmfr0;
 
-	parange = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1) & 0x7;
+	mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
+	parange = cpuid_feature_extract_unsigned_field(mmfr0,
+				ID_AA64MMFR0_PARANGE_SHIFT);
 	pa_max = id_aa64mmfr0_parange_to_phys_shift(parange);
 
 	/* Clamp the IPA limit to the PA size supported by the kernel */
@@ -395,7 +398,7 @@ void kvm_set_ipa_limit(void)
  */
 int kvm_arm_setup_stage2(struct kvm *kvm, unsigned long type)
 {
-	u64 vtcr = VTCR_EL2_FLAGS;
+	u64 vtcr = VTCR_EL2_FLAGS, mmfr0;
 	u32 parange, phys_shift;
 	u8 lvls;
 
@@ -411,7 +414,9 @@ 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;
+	mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
+	parange = cpuid_feature_extract_unsigned_field(mmfr0,
+				ID_AA64MMFR0_PARANGE_SHIFT);
 	if (parange > ID_AA64MMFR0_PARANGE_MAX)
 		parange = ID_AA64MMFR0_PARANGE_MAX;
 	vtcr |= parange << VTCR_EL2_PS_SHIFT;
-- 
2.20.1