Commit 7c1b058c authored by Robin Murphy's avatar Robin Murphy Committed by Joerg Roedel
Browse files

iommu/dma: Handle IOMMU API reserved regions 



Now that it's simple to discover the necessary reservations for a given
device/IOMMU combination, let's wire up the appropriate handling. Basic
reserved regions and direct-mapped regions we simply have to carve out
of IOVA space (the IOMMU core having already mapped the latter before
attaching the device). For hardware MSI regions, we also pre-populate
the cookie with matching msi_pages. That way, irqchip drivers which
normally assume MSIs to require mapping at the IOMMU can keep working
without having to special-case their iommu_dma_map_msi_msg() hook, or
indeed be aware at all of quirks preventing the IOMMU from translating
certain addresses.

Reviewed-by: default avatarEric Auger <eric.auger@redhat.com>
Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 938f1bbe

drivers/iommu/dma-iommu.c

+69 −7
Original line number Diff line number Diff line
@@ -184,6 +184,66 @@ static void iova_reserve_pci_windows(struct pci_dev *dev, 
	}

}



static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie,

		phys_addr_t start, phys_addr_t end)

{

	struct iova_domain *iovad = &cookie->iovad;

	struct iommu_dma_msi_page *msi_page;

	int i, num_pages;



	start -= iova_offset(iovad, start);

	num_pages = iova_align(iovad, end - start) >> iova_shift(iovad);



	msi_page = kcalloc(num_pages, sizeof(*msi_page), GFP_KERNEL);

	if (!msi_page)

		return -ENOMEM;



	for (i = 0; i < num_pages; i++) {

		msi_page[i].phys = start;

		msi_page[i].iova = start;

		INIT_LIST_HEAD(&msi_page[i].list);

		list_add(&msi_page[i].list, &cookie->msi_page_list);

		start += iovad->granule;

	}



	return 0;

}



static int iova_reserve_iommu_regions(struct device *dev,

		struct iommu_domain *domain)

{

	struct iommu_dma_cookie *cookie = domain->iova_cookie;

	struct iova_domain *iovad = &cookie->iovad;

	struct iommu_resv_region *region;

	LIST_HEAD(resv_regions);

	int ret = 0;



	if (dev_is_pci(dev))

		iova_reserve_pci_windows(to_pci_dev(dev), iovad);



	iommu_get_resv_regions(dev, &resv_regions);

	list_for_each_entry(region, &resv_regions, list) {

		unsigned long lo, hi;



		/* We ARE the software that manages these! */

		if (region->type == IOMMU_RESV_SW_MSI)

			continue;



		lo = iova_pfn(iovad, region->start);

		hi = iova_pfn(iovad, region->start + region->length - 1);

		reserve_iova(iovad, lo, hi);



		if (region->type == IOMMU_RESV_MSI)

			ret = cookie_init_hw_msi_region(cookie, region->start,

					region->start + region->length);

		if (ret)

			break;

	}

	iommu_put_resv_regions(dev, &resv_regions);



	return ret;

}



/**

 * iommu_dma_init_domain - Initialise a DMA mapping domain

 * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
@@ -202,7 +262,6 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, 
	struct iommu_dma_cookie *cookie = domain->iova_cookie;

	struct iova_domain *iovad = &cookie->iovad;

	unsigned long order, base_pfn, end_pfn;

	bool pci = dev && dev_is_pci(dev);



	if (!cookie || cookie->type != IOMMU_DMA_IOVA_COOKIE)

		return -EINVAL;
@@ -232,7 +291,7 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, 
	 * leave the cache limit at the top of their range to save an rb_last()

	 * traversal on every allocation.

	 */

	if (pci)

	if (dev && dev_is_pci(dev))

		end_pfn &= DMA_BIT_MASK(32) >> order;



	/* start_pfn is always nonzero for an already-initialised domain */
@@ -247,12 +306,15 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, 
		 * area cache limit down for the benefit of the smaller one.

		 */

		iovad->dma_32bit_pfn = min(end_pfn, iovad->dma_32bit_pfn);

	} else {

		init_iova_domain(iovad, 1UL << order, base_pfn, end_pfn);

		if (pci)

			iova_reserve_pci_windows(to_pci_dev(dev), iovad);



		return 0;

	}



	init_iova_domain(iovad, 1UL << order, base_pfn, end_pfn);

	if (!dev)

		return 0;



	return iova_reserve_iommu_regions(dev, domain);

}

EXPORT_SYMBOL(iommu_dma_init_domain);

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