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Commit 7f760ddd authored by Joerg Roedel's avatar Joerg Roedel
Browse files

x86/amd-iommu: Cleanup attach/detach_device code 



This patch cleans up the attach_device and detach_device
paths and fixes reference counting while at it.

Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
parent 7c392cbe

arch/x86/kernel/amd_iommu.c

+58 −44
Original line number Diff line number Diff line
@@ -1329,7 +1329,6 @@ static bool dma_ops_domain(struct protection_domain *domain) 


static void set_dte_entry(u16 devid, struct protection_domain *domain)

{

	struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];

	u64 pte_root = virt_to_phys(domain->pt_root);



	BUG_ON(amd_iommu_pd_table[devid] != NULL);
@@ -1344,18 +1343,11 @@ static void set_dte_entry(u16 devid, struct protection_domain *domain) 


	amd_iommu_pd_table[devid] = domain;



	/* Do reference counting */

	domain->dev_iommu[iommu->index] += 1;

	domain->dev_cnt                 += 1;



	/* Flush the changes DTE entry */

	iommu_queue_inv_dev_entry(iommu, devid);

}



static void clear_dte_entry(u16 devid)

{

	struct protection_domain *domain = amd_iommu_pd_table[devid];

	struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];



	BUG_ON(domain == NULL);
@@ -1368,11 +1360,51 @@ static void clear_dte_entry(u16 devid) 
	amd_iommu_dev_table[devid].data[2] = 0;



	amd_iommu_apply_erratum_63(devid);

}



static void do_attach(struct device *dev, struct protection_domain *domain)

{

	struct iommu_dev_data *dev_data;

	struct amd_iommu *iommu;

	u16 devid;



	devid    = get_device_id(dev);

	iommu    = amd_iommu_rlookup_table[devid];

	dev_data = get_dev_data(dev);



	/* Update data structures */

	dev_data->domain = domain;

	list_add(&dev_data->list, &domain->dev_list);

	set_dte_entry(devid, domain);



	/* Do reference counting */

	domain->dev_iommu[iommu->index] += 1;

	domain->dev_cnt                 += 1;



	/* Flush the DTE entry */

	iommu_queue_inv_dev_entry(iommu, devid);

}



static void do_detach(struct device *dev)

{

	struct iommu_dev_data *dev_data;

	struct amd_iommu *iommu;

	u16 devid;



	devid    = get_device_id(dev);

	iommu    = amd_iommu_rlookup_table[devid];

	dev_data = get_dev_data(dev);



	/* decrease reference counters */

	domain->dev_iommu[iommu->index] -= 1;

	domain->dev_cnt                 -= 1;

	dev_data->domain->dev_iommu[iommu->index] -= 1;

	dev_data->domain->dev_cnt                 -= 1;



	/* Update data structures */

	dev_data->domain = NULL;

	list_del(&dev_data->list);

	clear_dte_entry(devid);



	/* Flush the DTE entry */

	iommu_queue_inv_dev_entry(iommu, devid);

}
@@ -1384,12 +1416,10 @@ static int __attach_device(struct device *dev, 
			   struct protection_domain *domain)

{

	struct iommu_dev_data *dev_data, *alias_data;

	u16 devid, alias;



	devid      = get_device_id(dev);

	alias      = amd_iommu_alias_table[devid];

	dev_data   = get_dev_data(dev);

	alias_data = get_dev_data(dev_data->alias);



	if (!alias_data)

		return -EINVAL;
@@ -1406,21 +1436,16 @@ static int __attach_device(struct device *dev, 
		return -EBUSY;



	/* Do real assignment */

	if (alias != devid) {

		if (alias_data->domain == NULL) {

			alias_data->domain = domain;

			list_add(&alias_data->list, &domain->dev_list);

			set_dte_entry(alias, domain);

		}

	if (dev_data->alias != dev) {

		alias_data = get_dev_data(dev_data->alias);

		if (alias_data->domain == NULL)

			do_attach(dev_data->alias, domain);



		atomic_inc(&alias_data->bind);

	}



	if (dev_data->domain == NULL) {

		dev_data->domain = domain;

		list_add(&dev_data->list, &domain->dev_list);

		set_dte_entry(devid, domain);

	}

	if (dev_data->domain == NULL)

		do_attach(dev, domain);



	atomic_inc(&dev_data->bind);
@@ -1459,35 +1484,24 @@ static int attach_device(struct device *dev, 
 */

static void __detach_device(struct device *dev)

{

	u16 devid = get_device_id(dev), alias;

	struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];

	struct iommu_dev_data *dev_data = get_dev_data(dev);

	struct iommu_dev_data *alias_data;

	unsigned long flags;



	BUG_ON(!iommu);

	BUG_ON(!dev_data->domain);



	devid = get_device_id(dev);

	alias = get_device_id(dev_data->alias);

	spin_lock_irqsave(&dev_data->domain->lock, flags);



	if (devid != alias) {

	if (dev_data->alias != dev) {

		alias_data = get_dev_data(dev_data->alias);

		if (atomic_dec_and_test(&alias_data->bind)) {

			spin_lock_irqsave(&alias_data->domain->lock, flags);

			clear_dte_entry(alias);

			list_del(&alias_data->list);

			spin_unlock_irqrestore(&alias_data->domain->lock, flags);

			alias_data->domain = NULL;

		}

		if (atomic_dec_and_test(&alias_data->bind))

			do_detach(dev_data->alias);

	}



	if (atomic_dec_and_test(&dev_data->bind)) {

		spin_lock_irqsave(&dev_data->domain->lock, flags);

		clear_dte_entry(devid);

		list_del(&dev_data->list);

	if (atomic_dec_and_test(&dev_data->bind))

		do_detach(dev);



	spin_unlock_irqrestore(&dev_data->domain->lock, flags);

		dev_data->domain = NULL;

	}



	/*

	 * If we run in passthrough mode the device must be assigned to the