From: Ricardo Koller <ricarkol@google.com>
To: Oliver Upton <oliver.upton@linux.dev>
Cc: Ben Gardon <bgardon@google.com>,
pbonzini@redhat.com, maz@kernel.org, yuzenghui@huawei.com,
dmatlack@google.com, kvm@vger.kernel.org,
kvmarm@lists.linux.dev, qperret@google.com,
catalin.marinas@arm.com, andrew.jones@linux.dev,
seanjc@google.com, alexandru.elisei@arm.com,
suzuki.poulose@arm.com, eric.auger@redhat.com, gshan@redhat.com,
reijiw@google.com, rananta@google.com, ricarkol@gmail.com
Subject: Re: [PATCH 3/9] KVM: arm64: Add kvm_pgtable_stage2_split()
Date: Tue, 24 Jan 2023 09:18:33 -0800 [thread overview]
Message-ID: <CAOHnOrxGu2sU2+-M8+-nMiRc01BQvRug+S2rnBbK6HiCP_BMVw@mail.gmail.com> (raw)
In-Reply-To: <Y9ARN5hWlAYVFBoK@google.com>
On Tue, Jan 24, 2023 at 9:11 AM Oliver Upton <oliver.upton@linux.dev> wrote:
>
> On Tue, Jan 24, 2023 at 08:46:58AM -0800, Ricardo Koller wrote:
> > On Mon, Jan 23, 2023 at 05:03:23PM -0800, Ben Gardon wrote:
>
> [...]
>
> > > Would it be accurate to say:
> > > /* No huge pages can exist at the root level, so there's nothing to
> > > split here. */
> > >
> > > I think of "last level" as the lowest/leaf/4k level but
> > > KVM_PGTABLE_MAX_LEVELS - 1 is 3?
> >
> > Right, this is the 4k level.
> >
> > > Does ARM do the level numbering in
> > > reverse order to x86?
> >
> > Yes, it does. Interesting, x86 does
> >
> > iter->level--;
> >
> > while arm does:
> >
> > ret = __kvm_pgtable_walk(data, mm_ops, childp, level + 1);
> >
> > I don't think this numbering scheme is encoded anywhere in the PTEs, so
> > either architecture could use the other.
>
> The numbering we use in the page table walkers is deliberate, as it
> directly matches the Arm ARM. While we can certainly use either scheme
> I'd prefer we keep aligned with the architecture.
hehe, I was actually subtly suggesting our x86 friends to change their side.
>
> --
> Thanks,
> Oliver
next prev parent reply other threads:[~2023-01-24 17:18 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-13 3:49 [PATCH 0/9] KVM: arm64: Eager Huge-page splitting for dirty-logging Ricardo Koller
2023-01-13 3:49 ` [PATCH 1/9] KVM: arm64: Add KVM_PGTABLE_WALK_REMOVED into ctx->flags Ricardo Koller
2023-01-24 0:51 ` Ben Gardon
2023-01-24 0:56 ` Oliver Upton
2023-01-24 16:32 ` Ricardo Koller
2023-01-24 18:00 ` Ben Gardon
2023-01-26 18:48 ` Ricardo Koller
2023-01-24 16:30 ` Ricardo Koller
2023-01-13 3:49 ` [PATCH 2/9] KVM: arm64: Add helper for creating removed stage2 subtrees Ricardo Koller
2023-01-14 17:58 ` kernel test robot
2023-01-24 0:55 ` Ben Gardon
2023-01-24 16:35 ` Ricardo Koller
2023-01-24 17:07 ` Oliver Upton
2023-01-13 3:49 ` [PATCH 3/9] KVM: arm64: Add kvm_pgtable_stage2_split() Ricardo Koller
2023-01-24 1:03 ` Ben Gardon
2023-01-24 16:46 ` Ricardo Koller
2023-01-24 17:11 ` Oliver Upton
2023-01-24 17:18 ` Ricardo Koller [this message]
2023-01-24 17:48 ` David Matlack
2023-01-24 20:28 ` Oliver Upton
2023-02-06 9:20 ` Zheng Chuan
2023-02-06 16:28 ` Ricardo Koller
2023-01-13 3:49 ` [PATCH 4/9] KVM: arm64: Refactor kvm_arch_commit_memory_region() Ricardo Koller
2023-01-13 3:49 ` [PATCH 5/9] KVM: arm64: Add kvm_uninit_stage2_mmu() Ricardo Koller
2023-01-13 3:49 ` [PATCH 6/9] KVM: arm64: Split huge pages when dirty logging is enabled Ricardo Koller
2023-01-24 17:52 ` Ben Gardon
2023-01-24 22:19 ` Oliver Upton
2023-01-24 22:45 ` Oliver Upton
2023-01-26 18:45 ` Ricardo Koller
2023-01-26 19:25 ` Ricardo Koller
2023-01-26 20:10 ` Marc Zyngier
2023-01-27 15:45 ` Ricardo Koller
2023-01-30 21:18 ` Oliver Upton
2023-01-31 1:18 ` Sean Christopherson
2023-01-31 17:45 ` Oliver Upton
2023-01-31 17:54 ` Sean Christopherson
2023-01-31 19:06 ` Oliver Upton
2023-01-31 18:01 ` David Matlack
2023-01-31 18:19 ` Ricardo Koller
2023-01-31 18:35 ` Oliver Upton
2023-01-31 10:31 ` Marc Zyngier
2023-01-31 10:28 ` Marc Zyngier
2023-02-06 16:35 ` Ricardo Koller
2023-01-13 3:49 ` [PATCH 7/9] KVM: arm64: Open-code kvm_mmu_write_protect_pt_masked() Ricardo Koller
2023-01-13 3:49 ` [PATCH 8/9] KVM: arm64: Split huge pages during KVM_CLEAR_DIRTY_LOG Ricardo Koller
2023-01-13 3:50 ` [PATCH 9/9] KVM: arm64: Use local TLBI on permission relaxation Ricardo Koller
2023-01-24 0:48 ` [PATCH 0/9] KVM: arm64: Eager Huge-page splitting for dirty-logging Ben Gardon
2023-01-24 16:50 ` Ricardo Koller
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