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Commit aa429318 authored by Alex Williamson's avatar Alex Williamson
Browse files

vfio/type1: Add extension to test DMA cache coherence of IOMMU 



Now that the type1 IOMMU backend can support IOMMU_CACHE, we need to
be able to test whether coherency is currently enforced.  Add an
extension for this.

Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 1ef3e2bc

drivers/vfio/vfio_iommu_type1.c

+21 −0
Original line number Diff line number Diff line
@@ -867,6 +867,23 @@ static void vfio_iommu_type1_release(void *iommu_data) 
	kfree(iommu);

}



static int vfio_domains_have_iommu_cache(struct vfio_iommu *iommu)

{

	struct vfio_domain *domain;

	int ret = 1;



	mutex_lock(&iommu->lock);

	list_for_each_entry(domain, &iommu->domain_list, next) {

		if (!(domain->prot & IOMMU_CACHE)) {

			ret = 0;

			break;

		}

	}

	mutex_unlock(&iommu->lock);



	return ret;

}



static long vfio_iommu_type1_ioctl(void *iommu_data,

				   unsigned int cmd, unsigned long arg)

{
@@ -878,6 +895,10 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, 
		case VFIO_TYPE1_IOMMU:

		case VFIO_TYPE1v2_IOMMU:

			return 1;

		case VFIO_DMA_CC_IOMMU:

			if (!iommu)

				return 0;

			return vfio_domains_have_iommu_cache(iommu);

		default:

			return 0;

		}

include/uapi/linux/vfio.h

+5 −0
Original line number Diff line number Diff line
@@ -24,6 +24,11 @@ 
#define VFIO_TYPE1_IOMMU		1

#define VFIO_SPAPR_TCE_IOMMU		2

#define VFIO_TYPE1v2_IOMMU		3

/*

 * IOMMU enforces DMA cache coherence (ex. PCIe NoSnoop stripping).  This

 * capability is subject to change as groups are added or removed.

 */

#define VFIO_DMA_CC_IOMMU		4



/*

 * The IOCTL interface is designed for extensibility by embedding the