Re: [PATCH 07/24] iommu/dma: Move domain lookup into __iommu_dma_{map, unmap}

From: Robin Murphy <robin.murphy@arm.com>
To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>,
	Christoph Hellwig <hch@lst.de>
Cc: Tom Murphy <tmurphy@arista.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Linuxarm <linuxarm@huawei.com>,
	"iommu@lists.linux-foundation.org"
	<iommu@lists.linux-foundation.org>,
	"Wangzhou \(B\)" <wangzhou1@hisilicon.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 07/24] iommu/dma: Move domain lookup into __iommu_dma_{map, unmap}
Date: Mon, 29 Jul 2019 14:13:44 +0100	[thread overview]
Message-ID: <9027b5f1-545b-e11b-ca8f-f1e0bd701634@arm.com> (raw)
In-Reply-To: <5FC3163CFD30C246ABAA99954A238FA83F328FAB@lhreml524-mbb.china.huawei.com>

Hi Shameer,

On 29/07/2019 13:12, Shameerali Kolothum Thodi wrote:
> Hi Robin,
> 
>> -----Original Message-----
>> From: iommu-bounces@lists.linux-foundation.org
>> [mailto:iommu-bounces@lists.linux-foundation.org] On Behalf Of Christoph
>> Hellwig
>> Sent: 20 May 2019 08:30
>> To: Robin Murphy <robin.murphy@arm.com>
>> Cc: Tom Murphy <tmurphy@arista.com>; Catalin Marinas
>> <catalin.marinas@arm.com>; Will Deacon <will.deacon@arm.com>;
>> linux-kernel@vger.kernel.org; iommu@lists.linux-foundation.org;
>> linux-arm-kernel@lists.infradead.org
>> Subject: [PATCH 07/24] iommu/dma: Move domain lookup into
>> __iommu_dma_{map, unmap}
>>
>> From: Robin Murphy <robin.murphy@arm.com>
>>
>> Most of the callers don't care, and the couple that do already have the
>> domain to hand for other reasons are in slow paths where the (trivial)
>> overhead of a repeated lookup will be utterly immaterial.
> 
> On a Hisilicon ARM64 platform with 5.3-rc1, a F_TRANSALTION error from
> smmuv3 is reported when an attempt is made to assign a ixgbe vf dev to a
> Guest.
> 
> [  196.747107] arm-smmu-v3 arm-smmu-v3.0.auto: event 0x10 received:
> [  196.747109] arm-smmu-v3 arm-smmu-v3.0.auto: 0x00000180 00000010
> [  196.747110] arm-smmu-v3 arm-smmu-v3.0.auto: 0x0000020100000000
> [  196.747111] arm-smmu-v3 arm-smmu-v3.0.auto: 0x00000000ffffe040
> [  196.747113] arm-smmu-v3 arm-smmu-v3.0.auto: 0x00000000ffffe000
> 
> Git bisect points to this patch.
> 
> Please see below.
[...]
>> *iommu_dma_get_msi_page(struct device *dev,
>>   	if (!msi_page)
>>   		return NULL;
>>
>> -	iova = __iommu_dma_map(dev, msi_addr, size, prot, domain);
>> +	iova = __iommu_dma_map(dev, msi_addr, size, prot);
> 
> I think the domain here is retrieved using iommu_get_domain_for_dev()
> which may not be the default domain returned by iommu_get_dma_domain().

Urgh, yes, how did I manage to miss that? :(

I doubt this patch reverts cleanly, but I don't think it needs to be 
completely undone anyway; give me a moment...

Robin.

> 
> Please check and let me know.
> 
> Thanks,
> Shameer
> 
>>   	if (iova == DMA_MAPPING_ERROR)
>>   		goto out_free_page;
>> --
>> 2.20.1
>>
>> _______________________________________________
>> iommu mailing list
>> iommu@lists.linux-foundation.org
>> https://lists.linuxfoundation.org/mailman/listinfo/iommu

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