From: Catalin Marinas <catalin.marinas@arm.com>
To: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, maz@kernel.org,
will@kernel.org, oliver.upton@linux.dev, james.morse@arm.com,
suzuki.poulose@arm.com, yuzenghui@huawei.com,
zhukeqian1@huawei.com, jonathan.cameron@huawei.com,
linuxarm@huawei.com
Subject: Re: [RFC PATCH v2 6/8] KVM: arm64: Only write protect selected PTE
Date: Fri, 22 Sep 2023 17:00:40 +0100 [thread overview]
Message-ID: <ZQ26KE2bzEFYUpMc@arm.com> (raw)
In-Reply-To: <20230825093528.1637-7-shameerali.kolothum.thodi@huawei.com>
On Fri, Aug 25, 2023 at 10:35:26AM +0100, Shameer Kolothum wrote:
> From: Keqian Zhu <zhukeqian1@huawei.com>
>
> This function write protects all PTEs between the ffs and fls of mask.
> There may be unset bits between this range. It works well under pure
> software dirty log, as software dirty log is not working during this
> process.
>
> But it will unexpectly clear dirty status of PTE when hardware dirty
> log is enabled. So change it to only write protect selected PTE.
Ah, I did wonder about losing the dirty status. The equivalent to S1
would be for kvm_pgtable_stage2_wrprotect() to set a software dirty bit.
I'm only superficially familiar with how KVM does dirty tracking for
live migration. Does it need to first write-protect the pages and
disable DBM? Is DBM re-enabled later? Or does stage2_wp_range() with
your patches leave the DBM on? If the latter, the 'wp' aspect is a bit
confusing since DBM basically means writeable (and maybe clean). So
better to have something like stage2_clean_range().
--
Catalin
next prev parent reply other threads:[~2023-09-22 16:00 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-25 9:35 [RFC PATCH v2 0/8] KVM: arm64: Implement SW/HW combined dirty log Shameer Kolothum
2023-08-25 9:35 ` [RFC PATCH v2 1/8] arm64: cpufeature: Add API to report system support of HWDBM Shameer Kolothum
2023-08-25 9:35 ` [RFC PATCH v2 2/8] KVM: arm64: Add KVM_PGTABLE_WALK_HW_DBM for HW DBM support Shameer Kolothum
2023-09-15 22:05 ` Oliver Upton
2023-09-18 9:52 ` Shameerali Kolothum Thodi
2023-08-25 9:35 ` [RFC PATCH v2 3/8] KVM: arm64: Add some HW_DBM related pgtable interfaces Shameer Kolothum
2023-09-15 22:22 ` Oliver Upton
2023-09-18 9:53 ` Shameerali Kolothum Thodi
2023-09-22 15:24 ` Catalin Marinas
2023-09-22 17:49 ` Oliver Upton
2023-09-25 8:04 ` Shameerali Kolothum Thodi
2023-09-26 15:20 ` Catalin Marinas
2023-09-26 15:52 ` Shameerali Kolothum Thodi
2023-09-26 16:37 ` Catalin Marinas
2023-08-25 9:35 ` [RFC PATCH v2 4/8] KVM: arm64: Set DBM for previously writeable pages Shameer Kolothum
2023-09-15 22:54 ` Oliver Upton
2023-09-18 9:54 ` Shameerali Kolothum Thodi
2023-09-22 15:40 ` Catalin Marinas
2023-09-25 8:04 ` Shameerali Kolothum Thodi
2023-08-25 9:35 ` [RFC PATCH v2 5/8] KVM: arm64: Add some HW_DBM related mmu interfaces Shameer Kolothum
2023-08-25 9:35 ` [RFC PATCH v2 6/8] KVM: arm64: Only write protect selected PTE Shameer Kolothum
2023-09-22 16:00 ` Catalin Marinas [this message]
2023-09-22 16:59 ` Oliver Upton
2023-09-26 15:58 ` Catalin Marinas
2023-09-26 16:10 ` Catalin Marinas
2023-08-25 9:35 ` [RFC PATCH v2 7/8] KVM: arm64: Add KVM_CAP_ARM_HW_DBM Shameer Kolothum
2023-08-25 9:35 ` [RFC PATCH v2 8/8] KVM: arm64: Start up SW/HW combined dirty log Shameer Kolothum
2023-09-13 17:30 ` [RFC PATCH v2 0/8] KVM: arm64: Implement " Oliver Upton
2023-09-14 9:47 ` Shameerali Kolothum Thodi
2023-09-15 0:36 ` Oliver Upton
2023-09-18 9:55 ` Shameerali Kolothum Thodi
2023-09-20 21:12 ` Oliver Upton
2023-10-12 7:51 ` Shameerali Kolothum Thodi
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