From: Quentin Perret <qperret@google.com>
To: Marc Zyngier <maz@kernel.org>
Cc: Yanan Wang <wangyanan55@huawei.com>,
Will Deacon <will@kernel.org>,
Alexandru Elisei <alexandru.elisei@arm.com>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org,
Catalin Marinas <catalin.marinas@arm.com>,
James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Gavin Shan <gshan@redhat.com>,
wanghaibin.wang@huawei.com, zhukeqian1@huawei.com,
yuzenghui@huawei.com
Subject: Re: [PATCH v5 2/6] KVM: arm64: Move D-cache flush to the fault handlers
Date: Wed, 2 Jun 2021 10:49:50 +0000 [thread overview]
Message-ID: <YLdiTnfuhMimU4dE@google.com> (raw)
In-Reply-To: <877djc1sca.wl-maz@kernel.org>
On Wednesday 02 Jun 2021 at 11:19:49 (+0100), Marc Zyngier wrote:
> On Thu, 15 Apr 2021 12:50:28 +0100,
> > @@ -583,6 +589,7 @@ static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level,
> > {
> > kvm_pte_t new, old = *ptep;
> > u64 granule = kvm_granule_size(level), phys = data->phys;
> > + struct kvm_pgtable *pgt = data->mmu->pgt;
> > struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops;
> >
> > if (!kvm_block_mapping_supported(addr, end, phys, level))
> > @@ -606,6 +613,13 @@ static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level,
> > stage2_put_pte(ptep, data->mmu, addr, level, mm_ops);
> > }
> >
> > + /* Perform CMOs before installation of the guest stage-2 PTE */
> > + if (pgt->flags & KVM_PGTABLE_S2_GUEST) {
> > + if (stage2_pte_cacheable(pgt, new) && !stage2_has_fwb(pgt))
> > + __flush_dcache_area(mm_ops->phys_to_virt(phys),
> > + granule);
> > + }
>
> Rather than this, why not provide new callbacks in mm_ops, even if we
> have to provide one that is specific to guests (and let the protected
> stuff do its own thing)?
Ack, an optional callback in the mm_ops sounds much nicer.
> One thing I really dislike though is that the page-table code is
> starting to be littered with things that are not directly related to
> page tables. We are re-creating the user_mem_abort() mess in a
> different place.
+1, we should probably keep the page-table code as close as possible
to a standalone and architecturally-compliant library as opposed to a
mess of unrelated logic, simply because that will lead to a cleaner and
more maintainable design in the long run, and because that will ease the
interoperability with EL2 in protected mode.
Thanks,
Quentin
next prev parent reply other threads:[~2021-06-02 10:51 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-15 11:50 [PATCH v5 0/6] KVM: arm64: Improve efficiency of stage2 page table Yanan Wang
2021-04-15 11:50 ` [PATCH v5 1/6] KVM: arm64: Introduce KVM_PGTABLE_S2_GUEST stage-2 flag Yanan Wang
2021-06-02 10:43 ` Quentin Perret
2021-06-03 12:36 ` wangyanan (Y)
2021-04-15 11:50 ` [PATCH v5 2/6] KVM: arm64: Move D-cache flush to the fault handlers Yanan Wang
[not found] ` <877djc1sca.wl-maz@kernel.org>
2021-06-02 10:49 ` Quentin Perret [this message]
2021-06-03 12:33 ` wangyanan (Y)
2021-04-15 11:50 ` [PATCH v5 3/6] KVM: arm64: Add mm_ops member for structure stage2_attr_data Yanan Wang
2021-04-15 11:50 ` [PATCH v5 4/6] KVM: arm64: Provide invalidate_icache_range at non-VHE EL2 Yanan Wang
[not found] ` <875yyw1s73.wl-maz@kernel.org>
2021-06-03 12:34 ` wangyanan (Y)
2021-04-15 11:50 ` [PATCH v5 5/6] KVM: arm64: Move I-cache flush to the fault handlers Yanan Wang
2021-06-02 10:58 ` Quentin Perret
2021-06-03 12:35 ` wangyanan (Y)
2021-04-15 11:50 ` [PATCH v5 6/6] KVM: arm64: Distinguish cases of memcache allocations completely Yanan Wang
2021-06-02 11:07 ` Quentin Perret
2021-06-03 12:52 ` wangyanan (Y)
2021-05-12 12:54 ` [PATCH v5 0/6] KVM: arm64: Improve efficiency of stage2 page table wangyanan (Y)
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