Re: [PATCH v4 5/6] iommu/dma: Simplify calls to iommu_setup_dma_ops()

From: Eric Auger <eric.auger@redhat.com>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>,
	rjw@rjwysocki.net, lenb@kernel.org, joro@8bytes.org,
	mst@redhat.com
Cc: will@kernel.org, catalin.marinas@arm.com,
	baolu.lu@linux.intel.com, dwmw2@infradead.org,
	linux-acpi@vger.kernel.org, iommu@lists.linux-foundation.org,
	virtualization@lists.linux-foundation.org,
	linux-arm-kernel@lists.infradead.org, sebastien.boeuf@intel.com,
	robin.murphy@arm.com, kevin.tian@intel.com,
	lorenzo.pieralisi@arm.com, guohanjun@huawei.com,
	sudeep.holla@arm.com
Subject: Re: [PATCH v4 5/6] iommu/dma: Simplify calls to iommu_setup_dma_ops()
Date: Wed, 16 Jun 2021 17:50:49 +0200	[thread overview]
Message-ID: <210dbd62-cd04-209c-eec9-f0a4e706264d@redhat.com> (raw)
In-Reply-To: <20210610075130.67517-6-jean-philippe@linaro.org>

Hi Jean,

On 6/10/21 9:51 AM, Jean-Philippe Brucker wrote:
> dma-iommu uses the address bounds described in domain->geometry during
> IOVA allocation. The address size parameters of iommu_setup_dma_ops()
> are useful for describing additional limits set by the platform
> firmware, but aren't needed for drivers that call this function from
> probe_finalize(). The base parameter can be zero because dma-iommu
> already removes the first IOVA page, and the limit parameter can be
> U64_MAX because it's only checked against the domain geometry. Simplify
> calls to iommu_setup_dma_ops().
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Eric
> ---
>  drivers/iommu/amd/iommu.c   |  9 +--------
>  drivers/iommu/dma-iommu.c   |  4 +++-
>  drivers/iommu/intel/iommu.c | 10 +---------
>  3 files changed, 5 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> index 94b96d81fcfd..d3123bc05c08 100644
> --- a/drivers/iommu/amd/iommu.c
> +++ b/drivers/iommu/amd/iommu.c
> @@ -1708,14 +1708,7 @@ static struct iommu_device *amd_iommu_probe_device(struct device *dev)
>  
>  static void amd_iommu_probe_finalize(struct device *dev)
>  {
> -	struct iommu_domain *domain;
> -
> -	/* Domains are initialized for this device - have a look what we ended up with */
> -	domain = iommu_get_domain_for_dev(dev);
> -	if (domain->type == IOMMU_DOMAIN_DMA)
> -		iommu_setup_dma_ops(dev, IOVA_START_PFN << PAGE_SHIFT, U64_MAX);
> -	else
> -		set_dma_ops(dev, NULL);
> +	iommu_setup_dma_ops(dev, 0, U64_MAX);
>  }
>  
>  static void amd_iommu_release_device(struct device *dev)
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index c62e19bed302..175f8eaeb5b3 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -1322,7 +1322,9 @@ void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit)
>  	if (domain->type == IOMMU_DOMAIN_DMA) {
>  		if (iommu_dma_init_domain(domain, dma_base, dma_limit, dev))
>  			goto out_err;
> -		dev->dma_ops = &iommu_dma_ops;
> +		set_dma_ops(dev, &iommu_dma_ops);
> +	} else {
> +		set_dma_ops(dev, NULL);
>  	}
>  
>  	return;
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 85f18342603c..8d866940692a 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -5165,15 +5165,7 @@ static void intel_iommu_release_device(struct device *dev)
>  
>  static void intel_iommu_probe_finalize(struct device *dev)
>  {
> -	dma_addr_t base = IOVA_START_PFN << VTD_PAGE_SHIFT;
> -	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
> -	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
> -
> -	if (domain && domain->type == IOMMU_DOMAIN_DMA)
> -		iommu_setup_dma_ops(dev, base,
> -				    __DOMAIN_MAX_ADDR(dmar_domain->gaw));
> -	else
> -		set_dma_ops(dev, NULL);
> +	iommu_setup_dma_ops(dev, 0, U64_MAX);
>  }
>  
>  static void intel_iommu_get_resv_regions(struct device *device,

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