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From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
	Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org
Subject: [PATCH V2] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size
Date: Wed, 11 Aug 2021 16:41:15 +0530	[thread overview]
Message-ID: <1628680275-16578-1-git-send-email-anshuman.khandual@arm.com> (raw)

Even though ID_AA64MMFR0.PARANGE reports 52 bit PA size support, it cannot
be enabled as guest IPA size on 4K or 16K page size configurations. Hence
kvm_ipa_limit must be restricted to 48 bits. This change achieves required
IPA capping.

Before the commit c9b69a0cf0b4 ("KVM: arm64: Don't constrain maximum IPA
size based on host configuration"), the problem here would have been just
latent via PHYS_MASK_SHIFT (which earlier in turn capped kvm_ipa_limit),
which remains capped at 48 bits on 4K and 16K configs.

Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-kernel@vger.kernel.org
Fixes: c9b69a0cf0b4 ("KVM: arm64: Don't constrain maximum IPA size based on host configuration")
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
This applies on v5.14-rc5

Changes in V2:

- Replaced IS_ENABLED() based check with PAGE_SIZE based one per Marc
- Moved the conditional code block near parange assignment per Marc

Changes in V1:

https://lore.kernel.org/lkml/1628657549-27584-1-git-send-email-anshuman.khandual@arm.com/

 arch/arm64/kvm/reset.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index cba7872..78d4bd8 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -317,6 +317,14 @@ int kvm_set_ipa_limit(void)
 	mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
 	parange = cpuid_feature_extract_unsigned_field(mmfr0,
 				ID_AA64MMFR0_PARANGE_SHIFT);
+	/*
+	 * IPA size beyond 48 bits could not be supported
+	 * on either 4K or 16K page size. Hence let's cap
+	 * it to 48 bits, in case it's reported as larger
+	 * on the system.
+	 */
+	if (PAGE_SIZE != SZ_64K)
+		parange = min(parange, (unsigned int)ID_AA64MMFR0_PARANGE_48);
 
 	/*
 	 * Check with ARMv8.5-GTG that our PAGE_SIZE is supported at
-- 
2.7.4


WARNING: multiple messages have this Message-ID (diff)
From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	linux-kernel@vger.kernel.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	kvmarm@lists.cs.columbia.edu
Subject: [PATCH V2] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size
Date: Wed, 11 Aug 2021 16:41:15 +0530	[thread overview]
Message-ID: <1628680275-16578-1-git-send-email-anshuman.khandual@arm.com> (raw)

Even though ID_AA64MMFR0.PARANGE reports 52 bit PA size support, it cannot
be enabled as guest IPA size on 4K or 16K page size configurations. Hence
kvm_ipa_limit must be restricted to 48 bits. This change achieves required
IPA capping.

Before the commit c9b69a0cf0b4 ("KVM: arm64: Don't constrain maximum IPA
size based on host configuration"), the problem here would have been just
latent via PHYS_MASK_SHIFT (which earlier in turn capped kvm_ipa_limit),
which remains capped at 48 bits on 4K and 16K configs.

Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-kernel@vger.kernel.org
Fixes: c9b69a0cf0b4 ("KVM: arm64: Don't constrain maximum IPA size based on host configuration")
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
This applies on v5.14-rc5

Changes in V2:

- Replaced IS_ENABLED() based check with PAGE_SIZE based one per Marc
- Moved the conditional code block near parange assignment per Marc

Changes in V1:

https://lore.kernel.org/lkml/1628657549-27584-1-git-send-email-anshuman.khandual@arm.com/

 arch/arm64/kvm/reset.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index cba7872..78d4bd8 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -317,6 +317,14 @@ int kvm_set_ipa_limit(void)
 	mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
 	parange = cpuid_feature_extract_unsigned_field(mmfr0,
 				ID_AA64MMFR0_PARANGE_SHIFT);
+	/*
+	 * IPA size beyond 48 bits could not be supported
+	 * on either 4K or 16K page size. Hence let's cap
+	 * it to 48 bits, in case it's reported as larger
+	 * on the system.
+	 */
+	if (PAGE_SIZE != SZ_64K)
+		parange = min(parange, (unsigned int)ID_AA64MMFR0_PARANGE_48);
 
 	/*
 	 * Check with ARMv8.5-GTG that our PAGE_SIZE is supported at
-- 
2.7.4

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

WARNING: multiple messages have this Message-ID (diff)
From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
	Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org
Subject: [PATCH V2] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size
Date: Wed, 11 Aug 2021 16:41:15 +0530	[thread overview]
Message-ID: <1628680275-16578-1-git-send-email-anshuman.khandual@arm.com> (raw)

Even though ID_AA64MMFR0.PARANGE reports 52 bit PA size support, it cannot
be enabled as guest IPA size on 4K or 16K page size configurations. Hence
kvm_ipa_limit must be restricted to 48 bits. This change achieves required
IPA capping.

Before the commit c9b69a0cf0b4 ("KVM: arm64: Don't constrain maximum IPA
size based on host configuration"), the problem here would have been just
latent via PHYS_MASK_SHIFT (which earlier in turn capped kvm_ipa_limit),
which remains capped at 48 bits on 4K and 16K configs.

Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: kvmarm@lists.cs.columbia.edu
Cc: linux-kernel@vger.kernel.org
Fixes: c9b69a0cf0b4 ("KVM: arm64: Don't constrain maximum IPA size based on host configuration")
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
This applies on v5.14-rc5

Changes in V2:

- Replaced IS_ENABLED() based check with PAGE_SIZE based one per Marc
- Moved the conditional code block near parange assignment per Marc

Changes in V1:

https://lore.kernel.org/lkml/1628657549-27584-1-git-send-email-anshuman.khandual@arm.com/

 arch/arm64/kvm/reset.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index cba7872..78d4bd8 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -317,6 +317,14 @@ int kvm_set_ipa_limit(void)
 	mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
 	parange = cpuid_feature_extract_unsigned_field(mmfr0,
 				ID_AA64MMFR0_PARANGE_SHIFT);
+	/*
+	 * IPA size beyond 48 bits could not be supported
+	 * on either 4K or 16K page size. Hence let's cap
+	 * it to 48 bits, in case it's reported as larger
+	 * on the system.
+	 */
+	if (PAGE_SIZE != SZ_64K)
+		parange = min(parange, (unsigned int)ID_AA64MMFR0_PARANGE_48);
 
 	/*
 	 * Check with ARMv8.5-GTG that our PAGE_SIZE is supported at
-- 
2.7.4


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

             reply	other threads:[~2021-08-11 11:10 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-11 11:11 Anshuman Khandual [this message]
2021-08-11 11:11 ` [PATCH V2] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size Anshuman Khandual
2021-08-11 11:11 ` Anshuman Khandual
2021-08-11 15:02 ` Marc Zyngier
2021-08-11 15:02   ` Marc Zyngier
2021-08-11 15:02   ` Marc Zyngier

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