Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH 1/1] iommu/arm-smmu-v3: add support for BBML
To:     Will Deacon <will@kernel.org>, Robin Murphy <robin.murphy@arm.com>
References: <20201126034230.777-1-thunder.leizhen@huawei.com>
 <20210122125132.GB24102@willie-the-truck>
 <aac11411-f6cd-f990-fe53-db0d8c07f3a0@huawei.com>
 <1bfd1ca0-953e-e943-f87e-144d5537bd0c@arm.com>
 <20210126101230.GA29204@willie-the-truck>
 <8a9685ec-67aa-824f-5429-f408bf79c5ab@huawei.com>
CC:     "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>,
        "Jean-Philippe Brucker" <jean-philippe@linaro.org>,
        Joerg Roedel <joro@8bytes.org>,
        "Yang Yingliang" <yangyingliang@huawei.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        iommu <iommu@lists.linux-foundation.org>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
From:   Keqian Zhu <zhukeqian1@huawei.com>
Message-ID: <32f4752f-6954-183a-a0c1-b5d719c85b67@huawei.com>
Date:   Wed, 27 Jan 2021 15:36:08 +0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101
 Thunderbird/45.7.1
MIME-Version: 1.0
In-Reply-To: <8a9685ec-67aa-824f-5429-f408bf79c5ab@huawei.com>
Content-Type: text/plain; charset="windows-1252"
Content-Transfer-Encoding: 7bit
Precedence: bulk


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?

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
> .
>