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Commit 2aac6304 authored by Omer Peleg's avatar Omer Peleg Committed by David Woodhouse
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iommu/vt-d: change intel-iommu to use IOVA frame numbers 



Make intel-iommu map/unmap/invalidate work with IOVA pfns instead of
pointers to "struct iova". This avoids using the iova struct from the IOVA
red-black tree and the resulting explicit find_iova() on unmap.

This patch will allow us to cache IOVAs in the next patch, in order to
avoid rbtree operations for the majority of map/unmap operations.

Note: In eliminating the find_iova() operation, we have also eliminated
the sanity check previously done in the unmap flow. Arguably, this was
overhead that is better avoided in production code, but it could be
brought back as a debug option for driver development.

Signed-off-by: default avatarOmer Peleg <omer@cs.technion.ac.il>
[mad@cs.technion.ac.il: rebased, fixed to not break iova api, 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 0824c592

drivers/iommu/intel-iommu.c

+29 −32
Original line number Diff line number Diff line
@@ -459,7 +459,7 @@ static LIST_HEAD(dmar_rmrr_units); 
static void flush_unmaps_timeout(unsigned long data);



struct deferred_flush_entry {

	struct iova *iova;

	unsigned long iova_pfn;

	unsigned long nrpages;

	struct dmar_domain *domain;

	struct page *freelist;
@@ -3353,7 +3353,7 @@ static int __init init_dmars(void) 
}



/* This takes a number of _MM_ pages, not VTD pages */

static struct iova *intel_alloc_iova(struct device *dev,

static unsigned long intel_alloc_iova(struct device *dev,

				     struct dmar_domain *domain,

				     unsigned long nrpages, uint64_t dma_mask)

{
@@ -3373,16 +3373,16 @@ static struct iova *intel_alloc_iova(struct device *dev, 
		iova = alloc_iova(&domain->iovad, nrpages,

				  IOVA_PFN(DMA_BIT_MASK(32)), 1);

		if (iova)

			return iova;

			return iova->pfn_lo;

	}

	iova = alloc_iova(&domain->iovad, nrpages, IOVA_PFN(dma_mask), 1);

	if (unlikely(!iova)) {

		pr_err("Allocating %ld-page iova for %s failed",

		       nrpages, dev_name(dev));

		return NULL;

		return 0;

	}



	return iova;

	return iova->pfn_lo;

}



static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
@@ -3480,7 +3480,7 @@ static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr, 
{

	struct dmar_domain *domain;

	phys_addr_t start_paddr;

	struct iova *iova;

	unsigned long iova_pfn;

	int prot = 0;

	int ret;

	struct intel_iommu *iommu;
@@ -3498,8 +3498,8 @@ static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr, 
	iommu = domain_get_iommu(domain);

	size = aligned_nrpages(paddr, size);



	iova = intel_alloc_iova(dev, domain, dma_to_mm_pfn(size), dma_mask);

	if (!iova)

	iova_pfn = intel_alloc_iova(dev, domain, dma_to_mm_pfn(size), dma_mask);

	if (!iova_pfn)

		goto error;



	/*
@@ -3517,7 +3517,7 @@ static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr, 
	 * might have two guest_addr mapping to the same host paddr, but this

	 * is not a big problem

	 */

	ret = domain_pfn_mapping(domain, mm_to_dma_pfn(iova->pfn_lo),

	ret = domain_pfn_mapping(domain, mm_to_dma_pfn(iova_pfn),

				 mm_to_dma_pfn(paddr_pfn), size, prot);

	if (ret)

		goto error;
@@ -3525,18 +3525,18 @@ static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr, 
	/* it's a non-present to present mapping. Only flush if caching mode */

	if (cap_caching_mode(iommu->cap))

		iommu_flush_iotlb_psi(iommu, domain,

				      mm_to_dma_pfn(iova->pfn_lo),

				      mm_to_dma_pfn(iova_pfn),

				      size, 0, 1);

	else

		iommu_flush_write_buffer(iommu);



	start_paddr = (phys_addr_t)iova->pfn_lo << PAGE_SHIFT;

	start_paddr = (phys_addr_t)iova_pfn << PAGE_SHIFT;

	start_paddr += paddr & ~PAGE_MASK;

	return start_paddr;



error:

	if (iova)

		__free_iova(&domain->iovad, iova);

	if (iova_pfn)

		free_iova(&domain->iovad, iova_pfn);

	pr_err("Device %s request: %zx@%llx dir %d --- failed\n",

		dev_name(dev), size, (unsigned long long)paddr, dir);

	return 0;
@@ -3576,7 +3576,7 @@ static void flush_unmaps(struct deferred_flush_data *flush_data) 
			unsigned long mask;

			struct deferred_flush_entry *entry =

						&flush_table->entries[j];

			struct iova *iova = entry->iova;

			unsigned long iova_pfn = entry->iova_pfn;

			unsigned long nrpages = entry->nrpages;

			struct dmar_domain *domain = entry->domain;

			struct page *freelist = entry->freelist;
@@ -3584,14 +3584,14 @@ static void flush_unmaps(struct deferred_flush_data *flush_data) 
			/* On real hardware multiple invalidations are expensive */

			if (cap_caching_mode(iommu->cap))

				iommu_flush_iotlb_psi(iommu, domain,

					mm_to_dma_pfn(iova->pfn_lo),

					mm_to_dma_pfn(iova_pfn),

					nrpages, !freelist, 0);

			else {

				mask = ilog2(nrpages);

				iommu_flush_dev_iotlb(domain,

						(uint64_t)iova->pfn_lo << PAGE_SHIFT, mask);

						(uint64_t)iova_pfn << PAGE_SHIFT, mask);

			}

			__free_iova(&domain->iovad, iova);

			free_iova(&domain->iovad, iova_pfn);

			if (freelist)

				dma_free_pagelist(freelist);

		}
@@ -3611,7 +3611,7 @@ static void flush_unmaps_timeout(unsigned long cpuid) 
	spin_unlock_irqrestore(&flush_data->lock, flags);

}



static void add_unmap(struct dmar_domain *dom, struct iova *iova,

static void add_unmap(struct dmar_domain *dom, unsigned long iova_pfn,

		      unsigned long nrpages, struct page *freelist)

{

	unsigned long flags;
@@ -3645,7 +3645,7 @@ static void add_unmap(struct dmar_domain *dom, struct iova *iova, 


	entry = &flush_data->tables[iommu_id].entries[entry_id];

	entry->domain = dom;

	entry->iova = iova;

	entry->iova_pfn = iova_pfn;

	entry->nrpages = nrpages;

	entry->freelist = freelist;
@@ -3664,7 +3664,7 @@ static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size) 
	struct dmar_domain *domain;

	unsigned long start_pfn, last_pfn;

	unsigned long nrpages;

	struct iova *iova;

	unsigned long iova_pfn;

	struct intel_iommu *iommu;

	struct page *freelist;
@@ -3676,13 +3676,10 @@ static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size) 


	iommu = domain_get_iommu(domain);



	iova = find_iova(&domain->iovad, IOVA_PFN(dev_addr));

	if (WARN_ONCE(!iova, "Driver unmaps unmatched page at PFN %llx\n",

		      (unsigned long long)dev_addr))

		return;

	iova_pfn = IOVA_PFN(dev_addr);



	nrpages = aligned_nrpages(dev_addr, size);

	start_pfn = mm_to_dma_pfn(iova->pfn_lo);

	start_pfn = mm_to_dma_pfn(iova_pfn);

	last_pfn = start_pfn + nrpages - 1;



	pr_debug("Device %s unmapping: pfn %lx-%lx\n",
@@ -3694,10 +3691,10 @@ static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size) 
		iommu_flush_iotlb_psi(iommu, domain, start_pfn,

				      nrpages, !freelist, 0);

		/* free iova */

		__free_iova(&domain->iovad, iova);

		free_iova(&domain->iovad, iova_pfn);

		dma_free_pagelist(freelist);

	} else {

		add_unmap(domain, iova, nrpages, freelist);

		add_unmap(domain, iova_pfn, nrpages, freelist);

		/*

		 * queue up the release of the unmap to save the 1/6th of the

		 * cpu used up by the iotlb flush operation...
@@ -3810,7 +3807,7 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele 
	struct dmar_domain *domain;

	size_t size = 0;

	int prot = 0;

	struct iova *iova = NULL;

	unsigned long iova_pfn;

	int ret;

	struct scatterlist *sg;

	unsigned long start_vpfn;
@@ -3829,9 +3826,9 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele 
	for_each_sg(sglist, sg, nelems, i)

		size += aligned_nrpages(sg->offset, sg->length);



	iova = intel_alloc_iova(dev, domain, dma_to_mm_pfn(size),

	iova_pfn = intel_alloc_iova(dev, domain, dma_to_mm_pfn(size),

				*dev->dma_mask);

	if (!iova) {

	if (!iova_pfn) {

		sglist->dma_length = 0;

		return 0;

	}
@@ -3846,13 +3843,13 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele 
	if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)

		prot |= DMA_PTE_WRITE;



	start_vpfn = mm_to_dma_pfn(iova->pfn_lo);

	start_vpfn = mm_to_dma_pfn(iova_pfn);



	ret = domain_sg_mapping(domain, start_vpfn, sglist, size, prot);

	if (unlikely(ret)) {

		dma_pte_free_pagetable(domain, start_vpfn,

				       start_vpfn + size - 1);

		__free_iova(&domain->iovad, iova);

		free_iova(&domain->iovad, iova_pfn);

		return 0;

	}