Re: [PATCH 5/8] iommu/dart: Use static global identity domains

From: Janne Grunau <janne@jannau.net>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alyssa Rosenzweig <alyssa@rosenzweig.io>,
	asahi@lists.linux.dev, Lu Baolu <baolu.lu@linux.intel.com>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	David Woodhouse <dwmw2@infradead.org>,
	iommu@lists.linux.dev, Joerg Roedel <joro@8bytes.org>,
	Kevin Tian <kevin.tian@intel.com>,
	linux-arm-kernel@lists.infradead.org,
	linuxppc-dev@lists.ozlabs.org, Hector Martin <marcan@marcan.st>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Sven Peter <sven@svenpeter.dev>, Will Deacon <will@kernel.org>
Subject: Re: [PATCH 5/8] iommu/dart: Use static global identity domains
Date: Tue, 26 Sep 2023 20:49:41 +0200	[thread overview]
Message-ID: <ZRMnxQvYErphUs1M@robin> (raw)
In-Reply-To: <5-v1-8060f06462cc+c0a39-dart_paging_jgg@nvidia.com>

Hej,

On Fri, Sep 22, 2023 at 02:07:56PM -0300, Jason Gunthorpe wrote:
> Move to the new static global for identity domains. Move the identity
> specific code to apple_dart_attach_dev_identity().
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/iommu/apple-dart.c | 41 ++++++++++++++++++++++++++++----------
>  1 file changed, 30 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
> index 6bc2ad2207c3da..424f779ccc34df 100644
> --- a/drivers/iommu/apple-dart.c
> +++ b/drivers/iommu/apple-dart.c
> @@ -658,11 +658,7 @@ static int apple_dart_attach_dev(struct iommu_domain *domain,
>  	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
>  	struct apple_dart_domain *dart_domain = to_dart_domain(domain);
>  
> -	if (cfg->stream_maps[0].dart->force_bypass &&
> -	    domain->type != IOMMU_DOMAIN_IDENTITY)
> -		return -EINVAL;
> -	if (!cfg->stream_maps[0].dart->supports_bypass &&
> -	    domain->type == IOMMU_DOMAIN_IDENTITY)
> +	if (cfg->stream_maps[0].dart->force_bypass)
>  		return -EINVAL;
>  
>  	ret = apple_dart_finalize_domain(domain, cfg);
> @@ -683,15 +679,37 @@ static int apple_dart_attach_dev(struct iommu_domain *domain,
>  		for_each_stream_map(i, cfg, stream_map)
>  			apple_dart_hw_disable_dma(stream_map);
>  		break;
> -	case IOMMU_DOMAIN_IDENTITY:
> -		for_each_stream_map(i, cfg, stream_map)
> -			apple_dart_hw_enable_bypass(stream_map);
> -		break;
> +	default:
> +		return -EINVAL;
>  	}
>  
>  	return ret;
>  }
>  
> +static int apple_dart_attach_dev_identity(struct iommu_domain *domain,
> +					  struct device *dev)
> +{
> +	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
> +	struct apple_dart_stream_map *stream_map;
> +	int i;
> +
> +	if (!cfg->stream_maps[0].dart->supports_bypass)
> +		return -EINVAL;
> +
> +	for_each_stream_map(i, cfg, stream_map)
> +		apple_dart_hw_enable_bypass(stream_map);
> +	return 0;
> +}
> +
> +static const struct iommu_domain_ops apple_dart_identity_ops = {
> +	.attach_dev = apple_dart_attach_dev_identity,
> +};
> +
> +static struct iommu_domain apple_dart_identity_domain = {
> +	.type = IOMMU_DOMAIN_IDENTITY,
> +	.ops = &apple_dart_identity_ops,
> +};
> +
>  static struct iommu_device *apple_dart_probe_device(struct device *dev)
>  {
>  	struct apple_dart_master_cfg *cfg = dev_iommu_priv_get(dev);
> @@ -722,7 +740,7 @@ static struct iommu_domain *apple_dart_domain_alloc(unsigned int type)
>  	struct apple_dart_domain *dart_domain;
>  
>  	if (type != IOMMU_DOMAIN_DMA && type != IOMMU_DOMAIN_UNMANAGED &&
> -	    type != IOMMU_DOMAIN_IDENTITY && type != IOMMU_DOMAIN_BLOCKED)
> +	    type != IOMMU_DOMAIN_BLOCKED)
>  		return NULL;
>  
>  	dart_domain = kzalloc(sizeof(*dart_domain), GFP_KERNEL);
> @@ -732,7 +750,7 @@ static struct iommu_domain *apple_dart_domain_alloc(unsigned int type)
>  	mutex_init(&dart_domain->init_lock);
>  
>  	/* no need to allocate pgtbl_ops or do any other finalization steps */
> -	if (type == IOMMU_DOMAIN_IDENTITY || type == IOMMU_DOMAIN_BLOCKED)
> +	if (type == IOMMU_DOMAIN_BLOCKED)
>  		dart_domain->finalized = true;
>  
>  	return &dart_domain->domain;
> @@ -947,6 +965,7 @@ static void apple_dart_get_resv_regions(struct device *dev,
>  }
>  
>  static const struct iommu_ops apple_dart_iommu_ops = {
> +	.identity_domain = &apple_dart_identity_domain,
>  	.domain_alloc = apple_dart_domain_alloc,
>  	.probe_device = apple_dart_probe_device,
>  	.release_device = apple_dart_release_device,

Reviewed-by: Janne Grunau <j@jannau.net>

best reagrds,
Janne