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From: Will Deacon <will@kernel.org>
To: Yanan Wang <wangyanan55@huawei.com>
Cc: jiangkunkun@huawei.com, Gavin Shan <gshan@redhat.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Marc Zyngier <maz@kernel.org>,
	wangjingyi11@huawei.com, Quentin Perret <qperret@google.com>,
	lushenming@huawei.com, linux-kernel@vger.kernel.org,
	yezengruan@huawei.com, James Morse <james.morse@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	yuzenghui@huawei.com, wanghaibin.wang@huawei.com,
	zhukeqian1@huawei.com,
	Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: Re: [PATCH v2 0/3] Fix several bugs in KVM stage 2 translation
Date: Tue, 1 Dec 2020 20:59:48 +0000	[thread overview]
Message-ID: <20201201205948.GA28178@willie-the-truck> (raw)
In-Reply-To: <20201201201034.116760-1-wangyanan55@huawei.com>

On Wed, Dec 02, 2020 at 04:10:31AM +0800, Yanan Wang wrote:
> When installing a new pte entry or updating an old valid entry in stage 2
> translation, we use get_page()/put_page() to record page_count of the page-table
> pages. PATCH 1/3 aims to fix incorrect use of get_page()/put_page() in stage 2,
> which might make page-table pages unable to be freed when unmapping a range.
> 
> When dirty logging of a guest with hugepages is finished, we should merge tables
> back into a block entry if adjustment of huge mapping is found necessary.
> In addition to installing the block entry, we should not only free the non-huge
> page-table pages but also invalidate all the TLB entries of non-huge mappings for
> the block. PATCH 2/3 adds enough TLBI when merging tables into a block entry.
> 
> The rewrite of page-table code and fault handling add two different handlers
> for "just relaxing permissions" and "map by stage2 page-table walk", that's
> good improvement. Yet, in function user_mem_abort(), conditions where we choose
> the above two fault handlers are not strictly distinguished. This will causes
> guest errors such as infinite-loop (soft lockup will occur in result), because of
> calling the inappropriate fault handler. So, a solution that can strictly
> distinguish conditions is introduced in PATCH 3/3.

For the series:

Acked-by: Will Deacon <will@kernel.org>

Thanks for reporting these, helping me to understand the issues and then
spinning a v2 so promptly.

Will

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  parent reply	other threads:[~2020-12-01 21:01 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-01 20:10 [PATCH v2 0/3] Fix several bugs in KVM stage 2 translation Yanan Wang
2020-12-01 20:10 ` [PATCH v2 1/3] KVM: arm64: Fix possible memory leak in kvm stage2 Yanan Wang
2020-12-01 20:10 ` [PATCH v2 2/3] KVM: arm64: Fix handling of merging tables into a block entry Yanan Wang
2020-12-01 20:10 ` [PATCH v2 3/3] KVM: arm64: Add usage of stage 2 fault lookup level in user_mem_abort() Yanan Wang
2020-12-01 20:59 ` Will Deacon [this message]
2020-12-02 12:00   ` [PATCH v2 0/3] Fix several bugs in KVM stage 2 translation wangyanan (Y)
2020-12-02 12:23     ` Marc Zyngier
2020-12-02 12:50       ` wangyanan (Y)
2020-12-02 12:24 ` Marc Zyngier

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