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From: Quentin Perret <qperret@google.com>
To: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	kernel-team@android.com, kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 02/20] KVM: arm64: Add support for creating kernel-agnostic stage-1 page tables
Date: Fri, 31 Jul 2020 09:36:06 +0100
Message-ID: <20200731083606.GA3213389@google.com> (raw)
In-Reply-To: <20200731082208.GA26291@willie-the-truck>

On Friday 31 Jul 2020 at 09:22:15 (+0100), Will Deacon wrote:
> No, I think you're right. The hyp stage-1 PGD is always a single page, so I
> can simplify the free() path.

OK, cool. The current code does support concatenated pgds for the hyp
stage 1, which is what confused me. Would you mind adding something to
the commit message explaining why this is no longer needed or something?
Or at least mention it here so I understand :) ?

> At one point, I had a common free() path for
> stage-1 and stage-2, but that didn't last very long, as the stage-2
> page-table pages are refcounted so you end up having to deal with them
> differently anyway.

Right, though refcounting the pages for stage 1 might be a good idea
too. The current code does it, and I think we'll need it later on for
the Protected KVM stuff as unmap() will be needed for stage 1 as well.
I'm fine if this is done in a separate series, though. I don't think we
need any of that just yet, so we can definitely start 'simple'.

Cheers,
Quentin
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Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-30 15:33 [PATCH 00/20] KVM: arm64: Rewrite page-table code and fault handling Will Deacon
2020-07-30 15:33 ` [PATCH 01/20] KVM: arm64: Add stand-alone page-table walker infrastructure Will Deacon
2020-07-30 15:33 ` [PATCH 02/20] KVM: arm64: Add support for creating kernel-agnostic stage-1 page tables Will Deacon
2020-07-31  8:14   ` Quentin Perret
2020-07-31  8:19     ` Quentin Perret
2020-07-31  8:22       ` Will Deacon
2020-07-31  8:36         ` Quentin Perret [this message]
2020-07-31  9:06           ` Quentin Perret
2020-07-30 15:33 ` [PATCH 03/20] KVM: arm64: Use generic allocator for hyp stage-1 page-tables Will Deacon
2020-07-30 15:33 ` [PATCH 04/20] KVM: arm64: Add support for creating kernel-agnostic stage-2 page tables Will Deacon
2020-07-30 15:33 ` [PATCH 05/20] KVM: arm64: Add support for stage-2 map()/unmap() in generic page-table Will Deacon
2020-07-30 15:33 ` [PATCH 06/20] KVM: arm64: Convert kvm_phys_addr_ioremap() to generic page-table API Will Deacon
2020-07-30 15:33 ` [PATCH 07/20] KVM: arm64: Convert kvm_set_spte_hva() " Will Deacon
2020-07-30 15:33 ` [PATCH 08/20] KVM: arm64: Convert unmap_stage2_range() " Will Deacon
2020-07-30 15:33 ` [PATCH 09/20] KVM: arm64: Add support for stage-2 page-aging in generic page-table Will Deacon
2020-07-30 15:33 ` [PATCH 10/20] KVM: arm64: Convert page-aging and access faults to generic page-table API Will Deacon
2020-07-30 15:33 ` [PATCH 11/20] KVM: arm64: Add support for stage-2 write-protect in generic page-table Will Deacon
2020-07-30 15:33 ` [PATCH 12/20] KVM: arm64: Convert write-protect operation to generic page-table API Will Deacon
2020-07-30 15:33 ` [PATCH 13/20] KVM: arm64: Add support for stage-2 cache flushing in generic page-table Will Deacon
2020-07-30 15:34 ` [PATCH 14/20] KVM: arm64: Convert memslot cache-flushing code to generic page-table API Will Deacon
2020-07-30 15:34 ` [PATCH 15/20] KVM: arm64: Add support for relaxing stage-2 perms in generic page-table code Will Deacon
2020-07-30 15:34 ` [PATCH 16/20] KVM: arm64: Convert user_mem_abort() to generic page-table API Will Deacon
2020-07-30 15:34 ` [PATCH 17/20] KVM: arm64: Check the cookie instead of the pgd when modifying page-table Will Deacon
2020-07-30 15:34 ` [PATCH 18/20] KVM: arm64: Remove unused page-table code Will Deacon
2020-07-30 15:34 ` [PATCH 19/20] KVM: arm64: Remove unused 'pgd' field from 'struct kvm_s2_mmu' Will Deacon
2020-07-30 15:34 ` [PATCH 20/20] KVM: arm64: Don't constrain maximum IPA size based on host configuration Will Deacon
2020-08-03  8:17 ` [PATCH 00/20] KVM: arm64: Rewrite page-table code and fault handling Andrew Jones
2020-08-03 17:12   ` Quentin Perret

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