Re: [PATCH v7 1/7] iommu/arm-smmu-v3: Make default domain type of HiSilicon PTT device to identity

[John Garry <john.garry@huawei.com>]

On 07/04/2022 13:58, Yicong Yang wrote:
> The DMA operations of HiSilicon PTT device can only work properly with
> identical mappings. So add a quirk for the device to force the domain

I'm not sure if you meant to write "identity mappings".

> as passthrough.
> 
> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>

FWIW,

Reviewed-by: John Garry <john.garry@huawei.com>

> ---
>   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 16 ++++++++++++++++
>   1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 627a3ed5ee8f..5ec15ae2a9b1 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -2839,6 +2839,21 @@ static int arm_smmu_dev_disable_feature(struct device *dev,
>   	}
>   }
>   
> +#define IS_HISI_PTT_DEVICE(pdev)	((pdev)->vendor == PCI_VENDOR_ID_HUAWEI && \
> +					 (pdev)->device == 0xa12e)
> +
> +static int arm_smmu_def_domain_type(struct device *dev)
> +{
> +	if (dev_is_pci(dev)) {
> +		struct pci_dev *pdev = to_pci_dev(dev);
> +
> +		if (IS_HISI_PTT_DEVICE(pdev))
> +			return IOMMU_DOMAIN_IDENTITY;
> +	}
> +
> +	return 0;
> +}
> +
>   static struct iommu_ops arm_smmu_ops = {
>   	.capable		= arm_smmu_capable,
>   	.domain_alloc		= arm_smmu_domain_alloc,
> @@ -2856,6 +2871,7 @@ static struct iommu_ops arm_smmu_ops = {
>   	.sva_unbind		= arm_smmu_sva_unbind,
>   	.sva_get_pasid		= arm_smmu_sva_get_pasid,
>   	.page_response		= arm_smmu_page_response,
> +	.def_domain_type	= arm_smmu_def_domain_type,
>   	.pgsize_bitmap		= -1UL, /* Restricted during device attach */
>   	.owner			= THIS_MODULE,
>   	.default_domain_ops = &(const struct iommu_domain_ops) {