From: Robin Murphy <robin.murphy@arm.com>
To: Keqian Zhu <zhukeqian1@huawei.com>, Will Deacon <will@kernel.org>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>,
iommu <iommu@lists.linux-foundation.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
Yang Yingliang <yangyingliang@huawei.com>
Subject: Re: [PATCH 1/1] iommu/arm-smmu-v3: add support for BBML
Date: Wed, 27 Jan 2021 09:39:38 +0000 [thread overview]
Message-ID: <319e3532-4555-7431-9d6f-3c3b7c11a5d9@arm.com> (raw)
In-Reply-To: <32f4752f-6954-183a-a0c1-b5d719c85b67@huawei.com>
On 2021-01-27 07:36, Keqian Zhu wrote:
>
>
> On 2021/1/27 10:01, Leizhen (ThunderTown) wrote:
>>
>>
>> On 2021/1/26 18:12, Will Deacon wrote:
>>> On Mon, Jan 25, 2021 at 08:23:40PM +0000, Robin Murphy wrote:
>>>> Now we probably will need some degreee of BBML feature awareness for the
>>>> sake of SVA if and when we start using it for CPU pagetables, but I still
>>>> cannot see any need to consider it in io-pgtable.
>>>
>>> Agreed; I don't think this is something that io-pgtable should have to care
>>> about.
> Hi,
>
> I have a question here :-).
> If the old table is not live, then the break procedure seems unnecessary. Do I miss something?
The MMU is allowed to prefetch translations at any time, so not
following the proper update procedure could still potentially lead to a
TLB conflict, even if there's no device traffic to worry about disrupting.
Robin.
> Thanks,
> Keqian
>
>>
>> Yes, the SVA works in stall mode, and the failed device access requests are not
>> discarded.
>>
>> Let me look for examples. The BBML usage scenario was told by a former colleague.
>>
>>>
>>> Will
>>>
>>> .
>>>
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>> .
>>
> _______________________________________________
> iommu mailing list
> iommu@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/iommu
>
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next prev parent reply other threads:[~2021-01-27 9:41 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-26 3:42 [PATCH 1/1] iommu/arm-smmu-v3: add support for BBML Zhen Lei
2021-01-22 12:51 ` Will Deacon
2021-01-22 13:00 ` Robin Murphy
2021-01-22 13:21 ` Leizhen (ThunderTown)
2021-01-22 13:26 ` Will Deacon
2021-01-23 10:20 ` Leizhen (ThunderTown)
2021-01-25 19:54 ` Robin Murphy
2021-01-23 10:08 ` Leizhen (ThunderTown)
2021-01-25 20:23 ` Robin Murphy
2021-01-26 10:12 ` Will Deacon
2021-01-27 2:01 ` Leizhen (ThunderTown)
2021-01-27 7:36 ` Keqian Zhu
2021-01-27 9:39 ` Robin Murphy [this message]
2021-01-28 15:18 ` Keqian Zhu
2021-01-28 16:17 ` Robin Murphy
2021-01-29 6:12 ` Keqian Zhu
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