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Commit 0824c592 authored by Omer Peleg's avatar Omer Peleg Committed by David Woodhouse
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iommu/vt-d: avoid dev iotlb logic for domains with no dev iotlbs 



This patch avoids taking the device_domain_lock in iommu_flush_dev_iotlb()
for domains with no dev iotlb devices.

Signed-off-by: default avatarOmer Peleg <omer@cs.technion.ac.il>
[gvdl@google.com: fixed locking issues]
Signed-off-by: default avatarGodfrey van der Linden <gvdl@google.com>
[mad@cs.technion.ac.il: rebased and reworded the commit message]
Signed-off-by: default avatarAdam Morrison <mad@cs.technion.ac.il>
Reviewed-by: default avatarShaohua Li <shli@fb.com>
Reviewed-by: default avatarBen Serebrin <serebrin@google.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 769530e4

drivers/iommu/intel-iommu.c

+34 −0
Original line number Diff line number Diff line
@@ -391,6 +391,7 @@ struct dmar_domain { 
					 * domain ids are 16 bit wide according

					 * to VT-d spec, section 9.3 */



	bool has_iotlb_device;

	struct list_head devices;	/* all devices' list */

	struct iova_domain iovad;	/* iova's that belong to this domain */
@@ -1464,10 +1465,35 @@ iommu_support_dev_iotlb (struct dmar_domain *domain, struct intel_iommu *iommu, 
	return NULL;

}



static void domain_update_iotlb(struct dmar_domain *domain)

{

	struct device_domain_info *info;

	bool has_iotlb_device = false;



	assert_spin_locked(&device_domain_lock);



	list_for_each_entry(info, &domain->devices, link) {

		struct pci_dev *pdev;



		if (!info->dev || !dev_is_pci(info->dev))

			continue;



		pdev = to_pci_dev(info->dev);

		if (pdev->ats_enabled) {

			has_iotlb_device = true;

			break;

		}

	}



	domain->has_iotlb_device = has_iotlb_device;

}



static void iommu_enable_dev_iotlb(struct device_domain_info *info)

{

	struct pci_dev *pdev;



	assert_spin_locked(&device_domain_lock);



	if (!info || !dev_is_pci(info->dev))

		return;
@@ -1487,6 +1513,7 @@ static void iommu_enable_dev_iotlb(struct device_domain_info *info) 
#endif

	if (info->ats_supported && !pci_enable_ats(pdev, VTD_PAGE_SHIFT)) {

		info->ats_enabled = 1;

		domain_update_iotlb(info->domain);

		info->ats_qdep = pci_ats_queue_depth(pdev);

	}

}
@@ -1495,6 +1522,8 @@ static void iommu_disable_dev_iotlb(struct device_domain_info *info) 
{

	struct pci_dev *pdev;



	assert_spin_locked(&device_domain_lock);



	if (!dev_is_pci(info->dev))

		return;
@@ -1503,6 +1532,7 @@ static void iommu_disable_dev_iotlb(struct device_domain_info *info) 
	if (info->ats_enabled) {

		pci_disable_ats(pdev);

		info->ats_enabled = 0;

		domain_update_iotlb(info->domain);

	}

#ifdef CONFIG_INTEL_IOMMU_SVM

	if (info->pri_enabled) {
@@ -1523,6 +1553,9 @@ static void iommu_flush_dev_iotlb(struct dmar_domain *domain, 
	unsigned long flags;

	struct device_domain_info *info;



	if (!domain->has_iotlb_device)

		return;



	spin_lock_irqsave(&device_domain_lock, flags);

	list_for_each_entry(info, &domain->devices, link) {

		if (!info->ats_enabled)
@@ -1740,6 +1773,7 @@ static struct dmar_domain *alloc_domain(int flags) 
	memset(domain, 0, sizeof(*domain));

	domain->nid = -1;

	domain->flags = flags;

	domain->has_iotlb_device = false;

	INIT_LIST_HEAD(&domain->devices);



	return domain;