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Message-ID: <c735459b-ba25-d1e5-b20f-4205fab67060@linux.ibm.com>
Date:   Mon, 2 Jan 2023 19:18:20 +0100
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Subject: Re: [PATCH v3 1/7] s390/ism: Set DMA coherent mask
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To:     Niklas Schnelle <schnelle@linux.ibm.com>,
        Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Wenjia Zhang <wenjia@linux.ibm.com>
Cc:     Matthew Rosato <mjrosato@linux.ibm.com>,
        Gerd Bayer <gbayer@linux.ibm.com>,
        Pierre Morel <pmorel@linux.ibm.com>, iommu@lists.linux.dev,
        linux-s390@vger.kernel.org, borntraeger@linux.ibm.com,
        hca@linux.ibm.com, gor@linux.ibm.com,
        gerald.schaefer@linux.ibm.com, agordeev@linux.ibm.com,
        svens@linux.ibm.com, linux-kernel@vger.kernel.org,
        Julian Ruess <julianr@linux.ibm.com>
References: <20230102115619.2088685-1-schnelle@linux.ibm.com>
 <20230102115619.2088685-2-schnelle@linux.ibm.com>
From:   Alexandra Winter <wintera@linux.ibm.com>
In-Reply-To: <20230102115619.2088685-2-schnelle@linux.ibm.com>
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On 02.01.23 12:56, Niklas Schnelle wrote:
> A future change will convert the DMA API implementation from the
> architecture specific arch/s390/pci/pci_dma.c to using the common code
> drivers/iommu/dma-iommu.c which the utilizes the same IOMMU hardware
> through the s390-iommu driver. Unlike the s390 specific DMA API this
> requires devices to correctly call set the coherent mask to be allowed
			^^^correctly set ^^^	
> to use IOVAs >2^32 in dma_alloc_coherent(). This was however not done
> for ISM devices. ISM requires such addresses since currently the DMA
> aperture for PCI devices starts at 2^32 and all calls to
> dma_alloc_coherent() would thus fail.
> 
> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
> ---
> v1 -> v2:
> - Use dma_set_mask_and_coherent() (Christoph Hellwig)
> 
>  drivers/s390/net/ism_drv.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/s390/net/ism_drv.c b/drivers/s390/net/ism_drv.c
> index dfd401d9e362..aba03b613296 100644
> --- a/drivers/s390/net/ism_drv.c
> +++ b/drivers/s390/net/ism_drv.c
> @@ -557,7 +557,7 @@ static int ism_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>  	if (ret)
>  		goto err_disable;
>  
> -	ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
> +	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
>  	if (ret)
>  		goto err_resource;
>  

Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>