* [PATCH V2] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size
@ 2021-08-11 11:11 ` Anshuman Khandual
0 siblings, 0 replies; 6+ messages in thread
From: Anshuman Khandual @ 2021-08-11 11:11 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Anshuman Khandual, Marc Zyngier, James Morse, Alexandru Elisei,
Suzuki K Poulose, Catalin Marinas, Will Deacon, kvmarm,
linux-kernel
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
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH V2] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size
@ 2021-08-11 11:11 ` Anshuman Khandual
0 siblings, 0 replies; 6+ messages in thread
From: Anshuman Khandual @ 2021-08-11 11:11 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Will Deacon, Marc Zyngier, Anshuman Khandual, linux-kernel,
Catalin Marinas, kvmarm
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
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH V2] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size
@ 2021-08-11 11:11 ` Anshuman Khandual
0 siblings, 0 replies; 6+ messages in thread
From: Anshuman Khandual @ 2021-08-11 11:11 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Anshuman Khandual, Marc Zyngier, James Morse, Alexandru Elisei,
Suzuki K Poulose, Catalin Marinas, Will Deacon, kvmarm,
linux-kernel
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
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH V2] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size
2021-08-11 11:11 ` Anshuman Khandual
(?)
@ 2021-08-11 15:02 ` Marc Zyngier
-1 siblings, 0 replies; 6+ messages in thread
From: Marc Zyngier @ 2021-08-11 15:02 UTC (permalink / raw)
To: linux-arm-kernel, Anshuman Khandual
Cc: Catalin Marinas, Alexandru Elisei, James Morse, kvmarm,
linux-kernel, Suzuki K Poulose, Will Deacon
On Wed, 11 Aug 2021 16:41:15 +0530, Anshuman Khandual wrote:
> 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.
Applied to next, thanks!
[1/1] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size
commit: 5e5df9571c319fb107d7a523cc96fcc99961ee70
Cheers,
M.
--
Without deviation from the norm, progress is not possible.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH V2] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size
@ 2021-08-11 15:02 ` Marc Zyngier
0 siblings, 0 replies; 6+ messages in thread
From: Marc Zyngier @ 2021-08-11 15:02 UTC (permalink / raw)
To: linux-arm-kernel, Anshuman Khandual
Cc: Will Deacon, Catalin Marinas, linux-kernel, kvmarm
On Wed, 11 Aug 2021 16:41:15 +0530, Anshuman Khandual wrote:
> 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.
Applied to next, thanks!
[1/1] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size
commit: 5e5df9571c319fb107d7a523cc96fcc99961ee70
Cheers,
M.
--
Without deviation from the norm, progress is not possible.
_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH V2] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size
@ 2021-08-11 15:02 ` Marc Zyngier
0 siblings, 0 replies; 6+ messages in thread
From: Marc Zyngier @ 2021-08-11 15:02 UTC (permalink / raw)
To: linux-arm-kernel, Anshuman Khandual
Cc: Catalin Marinas, Alexandru Elisei, James Morse, kvmarm,
linux-kernel, Suzuki K Poulose, Will Deacon
On Wed, 11 Aug 2021 16:41:15 +0530, Anshuman Khandual wrote:
> 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.
Applied to next, thanks!
[1/1] KVM: arm64: Restrict IPA size to maximum 48 bits on 4K and 16K page size
commit: 5e5df9571c319fb107d7a523cc96fcc99961ee70
Cheers,
M.
--
Without deviation from the norm, progress is not possible.
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-08-11 15:04 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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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 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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