Re: [PATCH 05/26] iommu/vt-d: Calculate translation in domain_context_mapping_one

[Alex Williamson <alex.williamson@redhat.com>]

On Wed, 2015-08-05 at 17:18 +0200, Joerg Roedel wrote:
> From: Joerg Roedel <jroedel@suse.de>
> 
> There is no reason to pass the translation type through
> multiple layers. It can also be determined in the
> domain_context_mapping_one function directly.
> 
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
>  drivers/iommu/intel-iommu.c | 50 ++++++++++++++++++++++-----------------------
>  1 file changed, 24 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 58fc4bb..1a934f8 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -364,7 +364,8 @@ static inline int first_pte_in_page(struct dma_pte *pte)
>  static struct dmar_domain *si_domain;
>  static int hw_pass_through = 1;
>  
> -/* domain represents a virtual machine, more than one devices
> +/*
> + * Domain represents a virtual machine, more than one devices
>   * across iommus may be owned in one domain, e.g. kvm guest.
>   */
>  #define DOMAIN_FLAG_VIRTUAL_MACHINE	(1 << 0)
> @@ -638,6 +639,11 @@ static inline int domain_type_is_vm(struct dmar_domain *domain)
>  	return domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE;
>  }
>  
> +static inline int domain_type_is_si(struct dmar_domain *domain)
> +{
> +	return domain->flags & DOMAIN_FLAG_STATIC_IDENTITY;
> +}
> +
>  static inline int domain_type_is_vm_or_si(struct dmar_domain *domain)
>  {
>  	return domain->flags & (DOMAIN_FLAG_VIRTUAL_MACHINE |
> @@ -1904,21 +1910,24 @@ static void domain_exit(struct dmar_domain *domain)
>  
>  static int domain_context_mapping_one(struct dmar_domain *domain,
>  				      struct intel_iommu *iommu,
> -				      u8 bus, u8 devfn, int translation)
> +				      u8 bus, u8 devfn)
>  {
> +	int translation = CONTEXT_TT_MULTI_LEVEL;
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> +	struct device_domain_info *info = NULL;
>  	struct context_entry *context;
>  	unsigned long flags;
>  	struct dma_pte *pgd;
>  	int id;
>  	int agaw;
> -	struct device_domain_info *info = NULL;
> +
> +	translation = CONTEXT_TT_MULTI_LEVEL;
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I'm sure this is already part of your cleanup.

> +	if (hw_pass_through && domain_type_is_si(domain))
> +		translation = CONTEXT_TT_PASS_THROUGH;
>  
>  	pr_debug("Set context mapping for %02x:%02x.%d\n",
>  		bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
>  
>  	BUG_ON(!domain->pgd);
> -	BUG_ON(translation != CONTEXT_TT_PASS_THROUGH &&
> -	       translation != CONTEXT_TT_MULTI_LEVEL);
>  
>  	spin_lock_irqsave(&iommu->lock, flags);
>  	context = iommu_context_addr(iommu, bus, devfn, 1);
> @@ -2010,7 +2019,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
>  struct domain_context_mapping_data {
>  	struct dmar_domain *domain;
>  	struct intel_iommu *iommu;
> -	int translation;
>  };
>  
>  static int domain_context_mapping_cb(struct pci_dev *pdev,
> @@ -2019,13 +2027,11 @@ static int domain_context_mapping_cb(struct pci_dev *pdev,
>  	struct domain_context_mapping_data *data = opaque;
>  
>  	return domain_context_mapping_one(data->domain, data->iommu,
> -					  PCI_BUS_NUM(alias), alias & 0xff,
> -					  data->translation);
> +					  PCI_BUS_NUM(alias), alias & 0xff);
>  }
>  
>  static int
> -domain_context_mapping(struct dmar_domain *domain, struct device *dev,
> -		       int translation)
> +domain_context_mapping(struct dmar_domain *domain, struct device *dev)
>  {
>  	struct intel_iommu *iommu;
>  	u8 bus, devfn;
> @@ -2036,12 +2042,10 @@ domain_context_mapping(struct dmar_domain *domain, struct device *dev,
>  		return -ENODEV;
>  
>  	if (!dev_is_pci(dev))
> -		return domain_context_mapping_one(domain, iommu, bus, devfn,
> -						  translation);
> +		return domain_context_mapping_one(domain, iommu, bus, devfn);
>  
>  	data.domain = domain;
>  	data.iommu = iommu;
> -	data.translation = translation;
>  
>  	return pci_for_each_dma_alias(to_pci_dev(dev),
>  				      &domain_context_mapping_cb, &data);
> @@ -2508,7 +2512,7 @@ static int iommu_prepare_identity_map(struct device *dev,
>  		goto error;
>  
>  	/* context entry init */
> -	ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
> +	ret = domain_context_mapping(domain, dev);
>  	if (ret)
>  		goto error;
>  
> @@ -2621,8 +2625,7 @@ static int identity_mapping(struct device *dev)
>  	return 0;
>  }
>  
> -static int domain_add_dev_info(struct dmar_domain *domain,
> -			       struct device *dev, int translation)
> +static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
>  {
>  	struct dmar_domain *ndomain;
>  	struct intel_iommu *iommu;
> @@ -2637,7 +2640,7 @@ static int domain_add_dev_info(struct dmar_domain *domain,
>  	if (ndomain != domain)
>  		return -EBUSY;
>  
> -	ret = domain_context_mapping(domain, dev, translation);
> +	ret = domain_context_mapping(domain, dev);
>  	if (ret) {
>  		domain_remove_one_dev_info(domain, dev);
>  		return ret;
> @@ -2782,9 +2785,7 @@ static int __init dev_prepare_static_identity_mapping(struct device *dev, int hw
>  	if (!iommu_should_identity_map(dev, 1))
>  		return 0;
>  
> -	ret = domain_add_dev_info(si_domain, dev,
> -				  hw ? CONTEXT_TT_PASS_THROUGH :
> -				       CONTEXT_TT_MULTI_LEVEL);
> +	ret = domain_add_dev_info(si_domain, dev);
>  	if (!ret)
>  		pr_info("%s identity mapping for device %s\n",
>  			hw ? "Hardware" : "Software", dev_name(dev));
> @@ -3311,7 +3312,7 @@ static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
>  
>  	/* make sure context mapping is ok */
>  	if (unlikely(!domain_context_mapped(dev))) {
> -		ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
> +		ret = domain_context_mapping(domain, dev);
>  		if (ret) {
>  			pr_err("Domain context map for %s failed\n",
>  			       dev_name(dev));
> @@ -3366,10 +3367,7 @@ static int iommu_no_mapping(struct device *dev)
>  		 */
>  		if (iommu_should_identity_map(dev, 0)) {
>  			int ret;
> -			ret = domain_add_dev_info(si_domain, dev,
> -						  hw_pass_through ?
> -						  CONTEXT_TT_PASS_THROUGH :
> -						  CONTEXT_TT_MULTI_LEVEL);
> +			ret = domain_add_dev_info(si_domain, dev);
>  			if (!ret) {
>  				pr_info("64bit %s uses identity mapping\n",
>  					dev_name(dev));
> @@ -4786,7 +4784,7 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
>  		dmar_domain->agaw--;
>  	}
>  
> -	return domain_add_dev_info(dmar_domain, dev, CONTEXT_TT_MULTI_LEVEL);
> +	return domain_add_dev_info(dmar_domain, dev);
>  }
>  
>  static void intel_iommu_detach_device(struct iommu_domain *domain,