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From: Alex Williamson <alex.williamson@redhat.com>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Kevin Tian <kevin.tian@intel.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Ashok Raj <ashok.raj@intel.com>,
	kvm@vger.kernel.org, Cornelia Huck <cohuck@redhat.com>,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v4 5/5] iommu/vt-d: Add is_aux_domain support
Date: Thu, 10 Sep 2020 16:05:56 -0600	[thread overview]
Message-ID: <20200910160556.15fe7acd@w520.home> (raw)
In-Reply-To: <20200901033422.22249-6-baolu.lu@linux.intel.com>

On Tue,  1 Sep 2020 11:34:22 +0800
Lu Baolu <baolu.lu@linux.intel.com> wrote:

> With subdevice information opt-in through iommu_ops.aux_at(de)tach_dev()
> interfaces, the vendor iommu driver is able to learn the knowledge about
> the relationships between the subdevices and the aux-domains. Implement
> is_aux_domain() support based on the relationship knowledges.
> 
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>  drivers/iommu/intel/iommu.c | 125 ++++++++++++++++++++++++++----------
>  include/linux/intel-iommu.h |  17 +++--
>  2 files changed, 103 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 3c12fd06856c..50431c7b2e71 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -334,6 +334,8 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
>  				     struct device *dev);
>  static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
>  					    dma_addr_t iova);
> +static bool intel_iommu_dev_feat_enabled(struct device *dev,
> +					 enum iommu_dev_features feat);
>  
>  #ifdef CONFIG_INTEL_IOMMU_DEFAULT_ON
>  int dmar_disabled = 0;
> @@ -1832,6 +1834,7 @@ static struct dmar_domain *alloc_domain(int flags)
>  		domain->flags |= DOMAIN_FLAG_USE_FIRST_LEVEL;
>  	domain->has_iotlb_device = false;
>  	INIT_LIST_HEAD(&domain->devices);
> +	INIT_LIST_HEAD(&domain->subdevices);
>  
>  	return domain;
>  }
> @@ -2580,7 +2583,7 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
>  	info->iommu = iommu;
>  	info->pasid_table = NULL;
>  	info->auxd_enabled = 0;
> -	INIT_LIST_HEAD(&info->auxiliary_domains);
> +	INIT_LIST_HEAD(&info->subdevices);
>  
>  	if (dev && dev_is_pci(dev)) {
>  		struct pci_dev *pdev = to_pci_dev(info->dev);
> @@ -5137,21 +5140,28 @@ static void intel_iommu_domain_free(struct iommu_domain *domain)
>  		domain_exit(to_dmar_domain(domain));
>  }
>  
> -/*
> - * Check whether a @domain could be attached to the @dev through the
> - * aux-domain attach/detach APIs.
> - */
> -static inline bool
> -is_aux_domain(struct device *dev, struct iommu_domain *domain)
> +/* Lookup subdev_info in the domain's subdevice siblings. */
> +static struct subdev_info *
> +subdev_lookup_domain(struct dmar_domain *domain, struct device *dev,
> +		     struct device *subdev)
>  {
> -	struct device_domain_info *info = get_domain_info(dev);
> +	struct subdev_info *sinfo = NULL, *tmp;
>  
> -	return info && info->auxd_enabled &&
> -			domain->type == IOMMU_DOMAIN_UNMANAGED;
> +	assert_spin_locked(&device_domain_lock);
> +
> +	list_for_each_entry(tmp, &domain->subdevices, link_domain) {
> +		if ((!dev || tmp->pdev == dev) && tmp->dev == subdev) {
> +			sinfo = tmp;
> +			break;
> +		}
> +	}
> +
> +	return sinfo;
>  }
>  
> -static void auxiliary_link_device(struct dmar_domain *domain,
> -				  struct device *dev)
> +static void
> +subdev_link_device(struct dmar_domain *domain, struct device *dev,
> +		   struct subdev_info *sinfo)
>  {
>  	struct device_domain_info *info = get_domain_info(dev);
>  
> @@ -5159,12 +5169,13 @@ static void auxiliary_link_device(struct dmar_domain *domain,
>  	if (WARN_ON(!info))
>  		return;
>  
> -	domain->auxd_refcnt++;
> -	list_add(&domain->auxd, &info->auxiliary_domains);
> +	list_add(&info->subdevices, &sinfo->link_phys);
> +	list_add(&domain->subdevices, &sinfo->link_domain);
>  }
>  
> -static void auxiliary_unlink_device(struct dmar_domain *domain,
> -				    struct device *dev)
> +static void
> +subdev_unlink_device(struct dmar_domain *domain, struct device *dev,
> +		     struct subdev_info *sinfo)
>  {
>  	struct device_domain_info *info = get_domain_info(dev);
>  
> @@ -5172,24 +5183,30 @@ static void auxiliary_unlink_device(struct dmar_domain *domain,
>  	if (WARN_ON(!info))
>  		return;
>  
> -	list_del(&domain->auxd);
> -	domain->auxd_refcnt--;
> +	list_del(&sinfo->link_phys);
> +	list_del(&sinfo->link_domain);
> +	kfree(sinfo);
>  
> -	if (!domain->auxd_refcnt && domain->default_pasid > 0)
> +	if (list_empty(&domain->subdevices) && domain->default_pasid > 0)
>  		ioasid_free(domain->default_pasid);
>  }
>  
> -static int aux_domain_add_dev(struct dmar_domain *domain,
> -			      struct device *dev)
> +static int aux_domain_add_dev(struct dmar_domain *domain, struct device *dev,
> +			      struct device *subdev)
>  {
>  	int ret;
>  	unsigned long flags;
>  	struct intel_iommu *iommu;
> +	struct subdev_info *sinfo;
>  
>  	iommu = device_to_iommu(dev, NULL, NULL);
>  	if (!iommu)
>  		return -ENODEV;
>  
> +	sinfo = kzalloc(sizeof(*sinfo), GFP_KERNEL);
> +	if (!sinfo)
> +		return -ENOMEM;
> +
>  	if (domain->default_pasid <= 0) {
>  		int pasid;
>  
> @@ -5199,7 +5216,8 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
>  				     NULL);
>  		if (pasid == INVALID_IOASID) {
>  			pr_err("Can't allocate default pasid\n");
> -			return -ENODEV;
> +			ret = -ENODEV;
> +			goto pasid_failed;
>  		}
>  		domain->default_pasid = pasid;
>  	}
> @@ -5225,7 +5243,10 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
>  		goto table_failed;
>  	spin_unlock(&iommu->lock);
>  
> -	auxiliary_link_device(domain, dev);
> +	sinfo->dev = subdev;
> +	sinfo->domain = domain;
> +	sinfo->pdev = dev;
> +	subdev_link_device(domain, dev, sinfo);


The unlink path frees sinfo, would it make more sense to pass subdev,
domain, and dev to the link function and let it allocate the sinfo
struct and return it on success?  I'm not sure if you're pre-allocating
it to avoid something hard to unwind, but it feels asymmetric between
the link and unlink semantics.  Thanks,

Alex


>  
>  	spin_unlock_irqrestore(&device_domain_lock, flags);
>  
> @@ -5236,27 +5257,36 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
>  attach_failed:
>  	spin_unlock(&iommu->lock);
>  	spin_unlock_irqrestore(&device_domain_lock, flags);
> -	if (!domain->auxd_refcnt && domain->default_pasid > 0)
> +	if (list_empty(&domain->subdevices) && domain->default_pasid > 0)
>  		ioasid_free(domain->default_pasid);
> +pasid_failed:
> +	kfree(sinfo);
>  
>  	return ret;
>  }
>  
> -static void aux_domain_remove_dev(struct dmar_domain *domain,
> -				  struct device *dev)
> +static void
> +aux_domain_remove_dev(struct dmar_domain *domain, struct device *dev,
> +		      struct device *subdev)
>  {
>  	struct device_domain_info *info;
>  	struct intel_iommu *iommu;
> +	struct subdev_info *sinfo;
>  	unsigned long flags;
>  
> -	if (!is_aux_domain(dev, &domain->domain))
> +	if (!intel_iommu_dev_feat_enabled(dev, IOMMU_DEV_FEAT_AUX) ||
> +	    domain->domain.type != IOMMU_DOMAIN_UNMANAGED)
>  		return;
>  
>  	spin_lock_irqsave(&device_domain_lock, flags);
>  	info = get_domain_info(dev);
>  	iommu = info->iommu;
> -
> -	auxiliary_unlink_device(domain, dev);
> +	sinfo = subdev_lookup_domain(domain, dev, subdev);
> +	if (!sinfo) {
> +		spin_unlock_irqrestore(&device_domain_lock, flags);
> +		return;
> +	}
> +	subdev_unlink_device(domain, dev, sinfo);
>  
>  	spin_lock(&iommu->lock);
>  	intel_pasid_tear_down_entry(iommu, dev, domain->default_pasid, false);
> @@ -5319,7 +5349,8 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
>  		return -EPERM;
>  	}
>  
> -	if (is_aux_domain(dev, domain))
> +	if (intel_iommu_dev_feat_enabled(dev, IOMMU_DEV_FEAT_AUX) &&
> +	    domain->type == IOMMU_DOMAIN_UNMANAGED)
>  		return -EPERM;
>  
>  	/* normally dev is not mapped */
> @@ -5344,14 +5375,15 @@ intel_iommu_aux_attach_device(struct iommu_domain *domain,
>  {
>  	int ret;
>  
> -	if (!is_aux_domain(dev, domain))
> +	if (!intel_iommu_dev_feat_enabled(dev, IOMMU_DEV_FEAT_AUX) ||
> +	    domain->type != IOMMU_DOMAIN_UNMANAGED)
>  		return -EPERM;
>  
>  	ret = prepare_domain_attach_device(domain, dev);
>  	if (ret)
>  		return ret;
>  
> -	return aux_domain_add_dev(to_dmar_domain(domain), dev);
> +	return aux_domain_add_dev(to_dmar_domain(domain), dev, subdev);
>  }
>  
>  static void intel_iommu_detach_device(struct iommu_domain *domain,
> @@ -5364,7 +5396,7 @@ static void
>  intel_iommu_aux_detach_device(struct iommu_domain *domain, struct device *dev,
>  			      struct device *subdev)
>  {
> -	aux_domain_remove_dev(to_dmar_domain(domain), dev);
> +	aux_domain_remove_dev(to_dmar_domain(domain), dev, subdev);
>  }
>  
>  /*
> @@ -6020,6 +6052,32 @@ static bool intel_iommu_is_attach_deferred(struct iommu_domain *domain,
>  	return attach_deferred(dev);
>  }
>  
> +static int
> +intel_iommu_domain_get_attr(struct iommu_domain *domain,
> +			    enum iommu_attr attr, void *data)
> +{
> +	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
> +	unsigned long flags;
> +	int ret;
> +
> +	if (domain->type != IOMMU_DOMAIN_UNMANAGED)
> +		return -EINVAL;
> +
> +	switch (attr) {
> +	case DOMAIN_ATTR_IS_AUX:
> +		spin_lock_irqsave(&device_domain_lock, flags);
> +		ret = !IS_ERR_OR_NULL(subdev_lookup_domain(dmar_domain,
> +							   NULL, data));
> +		spin_unlock_irqrestore(&device_domain_lock, flags);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
>  static int
>  intel_iommu_domain_set_attr(struct iommu_domain *domain,
>  			    enum iommu_attr attr, void *data)
> @@ -6073,6 +6131,7 @@ const struct iommu_ops intel_iommu_ops = {
>  	.domain_alloc		= intel_iommu_domain_alloc,
>  	.domain_free		= intel_iommu_domain_free,
>  	.domain_set_attr	= intel_iommu_domain_set_attr,
> +	.domain_get_attr	= intel_iommu_domain_get_attr,
>  	.attach_dev		= intel_iommu_attach_device,
>  	.detach_dev		= intel_iommu_detach_device,
>  	.aux_attach_dev		= intel_iommu_aux_attach_device,
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index b1ed2f25f7c0..47ba1904c691 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -526,11 +526,9 @@ struct dmar_domain {
>  					/* Domain ids per IOMMU. Use u16 since
>  					 * domain ids are 16 bit wide according
>  					 * to VT-d spec, section 9.3 */
> -	unsigned int	auxd_refcnt;	/* Refcount of auxiliary attaching */
> -
>  	bool has_iotlb_device;
>  	struct list_head devices;	/* all devices' list */
> -	struct list_head auxd;		/* link to device's auxiliary list */
> +	struct list_head subdevices;	/* all subdevices' list */
>  	struct iova_domain iovad;	/* iova's that belong to this domain */
>  
>  	struct dma_pte	*pgd;		/* virtual address */
> @@ -603,14 +601,21 @@ struct intel_iommu {
>  	struct dmar_drhd_unit *drhd;
>  };
>  
> +/* Per subdevice private data */
> +struct subdev_info {
> +	struct list_head link_phys;	/* link to phys device siblings */
> +	struct list_head link_domain;	/* link to domain siblings */
> +	struct device *pdev;		/* physical device derived from */
> +	struct device *dev;		/* subdevice node */
> +	struct dmar_domain *domain;	/* aux-domain */
> +};
> +
>  /* PCI domain-device relationship */
>  struct device_domain_info {
>  	struct list_head link;	/* link to domain siblings */
>  	struct list_head global; /* link to global list */
>  	struct list_head table;	/* link to pasid table */
> -	struct list_head auxiliary_domains; /* auxiliary domains
> -					     * attached to this device
> -					     */
> +	struct list_head subdevices; /* subdevices sibling */
>  	u32 segment;		/* PCI segment number */
>  	u8 bus;			/* PCI bus number */
>  	u8 devfn;		/* PCI devfn number */

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  reply	other threads:[~2020-09-10 22:06 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-01  3:34 [PATCH v4 0/5] iommu aux-domain APIs extensions Lu Baolu
2020-09-01  3:34 ` [PATCH v4 1/5] iommu: Add optional subdev in aux_at(de)tach ops Lu Baolu
2020-09-10 22:05   ` Alex Williamson
2020-09-14  2:48     ` Lu Baolu
2020-09-01  3:34 ` [PATCH v4 2/5] iommu: Add iommu_at(de)tach_subdev_group() Lu Baolu
2020-09-10 22:05   ` Alex Williamson
2020-09-14  3:02     ` Lu Baolu
2020-09-01  3:34 ` [PATCH v4 3/5] iommu: Add iommu_aux_get_domain_for_dev() Lu Baolu
2020-09-01  3:34 ` [PATCH v4 4/5] vfio/type1: Use iommu_aux_at(de)tach_group() APIs Lu Baolu
2020-09-01  3:34 ` [PATCH v4 5/5] iommu/vt-d: Add is_aux_domain support Lu Baolu
2020-09-10 22:05   ` Alex Williamson [this message]
2020-09-14  5:01     ` Lu Baolu

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