From: Oliver Upton <oliver.upton@linux.dev>
To: Ryan Roberts <ryan.roberts@arm.com>
Cc: Marc Zyngier <maz@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH v1 10/12] KVM: arm64: Rework logic to en/decode VTCR_EL2.{SL0, SL2} fields
Date: Tue, 20 Dec 2022 00:06:49 +0000 [thread overview]
Message-ID: <Y6D8mYpSY0K8EGO4@google.com> (raw)
In-Reply-To: <20221206135930.3277585-11-ryan.roberts@arm.com>
Hi Ryan,
On Tue, Dec 06, 2022 at 01:59:28PM +0000, Ryan Roberts wrote:
> In order to support 5 level translation, FEAT_LPA2 introduces the 1-bit
> SL2 field within VTCR_EL2 to extend the existing 2-bit SL0 field. The
> SL2[0]:SL0[1:0] encodings have no simple algorithmic relationship to the
> start levels they represent (that I can find, at least), so replace the
> existing macros with functions that do lookups to encode and decode the
> values. These new functions no longer make hardcoded assumptions about
> the maximum level and instead rely on KVM_PGTABLE_FIRST_LEVEL and
> KVM_PGTABLE_LAST_LEVEL.
>
> This is preparatory work for enabling 52-bit IPA for 4KB and 16KB pages
> with FEAT_LPA2.
>
> No functional change intended.
>
> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Why do we need to support 5-level paging at stage-2?
A configuration of start_level = 0, T0SZ = 12 with 4K paging would
result in 16 concatenated tables at level 0, avoiding the level -1
lookup altogether.
--
Thanks,
Oliver
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next prev parent reply other threads:[~2022-12-20 0:32 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-06 13:59 [PATCH v1 00/12] KVM: arm64: Support FEAT_LPA2 at hyp s1 and vm s2 Ryan Roberts
2022-12-06 13:59 ` [PATCH v1 01/12] arm64/mm: Add FEAT_LPA2 specific ID_AA64MMFR0.TGRAN[2] Ryan Roberts
2022-12-14 19:16 ` Oliver Upton
2022-12-15 0:53 ` Oliver Upton
2022-12-06 13:59 ` [PATCH v1 02/12] arm64/mm: Update tlb invalidation routines for FEAT_LPA2 Ryan Roberts
2022-12-06 13:59 ` [PATCH v1 03/12] KVM: arm64: Add new (V)TCR_EL2 field definitions " Ryan Roberts
2022-12-06 13:59 ` [PATCH v1 04/12] KVM: arm64: Plumbing to enable multiple pgtable formats Ryan Roberts
2022-12-06 13:59 ` [PATCH v1 05/12] KVM: arm64: Maintain page-table format info in struct kvm_pgtable Ryan Roberts
2022-12-19 19:45 ` Oliver Upton
2022-12-06 13:59 ` [PATCH v1 06/12] KVM: arm64: Use LPA2 page-tables for stage2 if HW supports it Ryan Roberts
2022-12-06 13:59 ` [PATCH v1 07/12] KVM: arm64: Use LPA2 page-tables for hyp stage1 " Ryan Roberts
2022-12-06 13:59 ` [PATCH v1 08/12] KVM: arm64: Insert PS field at TCR_EL2 assembly time Ryan Roberts
2022-12-06 13:59 ` [PATCH v1 09/12] KVM: arm64: Convert translation level parameter to s8 Ryan Roberts
2022-12-06 13:59 ` [PATCH v1 10/12] KVM: arm64: Rework logic to en/decode VTCR_EL2.{SL0, SL2} fields Ryan Roberts
2022-12-20 0:06 ` Oliver Upton [this message]
2022-12-20 9:01 ` Ryan Roberts
2022-12-20 18:08 ` Oliver Upton
2022-12-06 13:59 ` [PATCH v1 11/12] KVM: arm64: Support upto 5 levels of translation in kvm_pgtable Ryan Roberts
2022-12-06 13:59 ` [PATCH v1 12/12] KVM: arm64: Allow guests with >48-bit IPA size on FEAT_LPA2 systems Ryan Roberts
2022-12-15 0:52 ` [PATCH v1 00/12] KVM: arm64: Support FEAT_LPA2 at hyp s1 and vm s2 Oliver Upton
2022-12-15 9:33 ` Ryan Roberts
2022-12-15 18:12 ` Oliver Upton
2022-12-20 18:28 ` Oliver Upton
2023-02-20 14:17 ` Ryan Roberts
2023-02-22 20:42 ` Oliver Upton
2023-02-23 9:53 ` Catalin Marinas
2022-12-15 9:35 ` Marc Zyngier
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