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Subject[PATCH v3 1/6] iommu: Handle freelists when using deferred flushing in iommu drivers
Date
From: Tom Murphy <murphyt7@tcd.ie>

Allow the iommu_unmap_fast to return newly freed page table pages and
pass the freelist to queue_iova in the dma-iommu ops path.

This is useful for iommu drivers (in this case the intel iommu driver)
which need to wait for the ioTLB to be flushed before newly
free/unmapped page table pages can be freed. This way we can still batch
ioTLB free operations and handle the freelists.

Signed-off-by: Tom Murphy <murphyt7@tcd.ie>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/dma-iommu.c | 30 ++++++++++++++------
drivers/iommu/intel/iommu.c | 55 ++++++++++++++++++++++++-------------
include/linux/iommu.h | 1 +
3 files changed, 59 insertions(+), 27 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 5141d49a046b..82c071b2d5c8 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -50,6 +50,18 @@ struct iommu_dma_cookie {
struct iommu_domain *fq_domain;
};

+static void iommu_dma_entry_dtor(unsigned long data)
+{
+ struct page *freelist = (struct page *)data;
+
+ while (freelist) {
+ unsigned long p = (unsigned long)page_address(freelist);
+
+ freelist = freelist->freelist;
+ free_page(p);
+ }
+}
+
static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie)
{
if (cookie->type == IOMMU_DMA_IOVA_COOKIE)
@@ -344,7 +356,8 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
if (!cookie->fq_domain && !iommu_domain_get_attr(domain,
DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr) && attr) {
cookie->fq_domain = domain;
- init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all, NULL);
+ init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all,
+ iommu_dma_entry_dtor);
}

if (!dev)
@@ -438,7 +451,7 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain,
}

static void iommu_dma_free_iova(struct iommu_dma_cookie *cookie,
- dma_addr_t iova, size_t size)
+ dma_addr_t iova, size_t size, struct page *freelist)
{
struct iova_domain *iovad = &cookie->iovad;

@@ -447,7 +460,8 @@ static void iommu_dma_free_iova(struct iommu_dma_cookie *cookie,
cookie->msi_iova -= size;
else if (cookie->fq_domain) /* non-strict mode */
queue_iova(iovad, iova_pfn(iovad, iova),
- size >> iova_shift(iovad), 0);
+ size >> iova_shift(iovad),
+ (unsigned long)freelist);
else
free_iova_fast(iovad, iova_pfn(iovad, iova),
size >> iova_shift(iovad));
@@ -472,7 +486,7 @@ static void __iommu_dma_unmap(struct device *dev, dma_addr_t dma_addr,

if (!cookie->fq_domain)
iommu_tlb_sync(domain, &iotlb_gather);
- iommu_dma_free_iova(cookie, dma_addr, size);
+ iommu_dma_free_iova(cookie, dma_addr, size, iotlb_gather.freelist);
}

static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
@@ -494,7 +508,7 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
return DMA_MAPPING_ERROR;

if (iommu_map_atomic(domain, iova, phys - iova_off, size, prot)) {
- iommu_dma_free_iova(cookie, iova, size);
+ iommu_dma_free_iova(cookie, iova, size, NULL);
return DMA_MAPPING_ERROR;
}
return iova + iova_off;
@@ -649,7 +663,7 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
out_free_sg:
sg_free_table(&sgt);
out_free_iova:
- iommu_dma_free_iova(cookie, iova, size);
+ iommu_dma_free_iova(cookie, iova, size, NULL);
out_free_pages:
__iommu_dma_free_pages(pages, count);
return NULL;
@@ -900,7 +914,7 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
return __finalise_sg(dev, sg, nents, iova);

out_free_iova:
- iommu_dma_free_iova(cookie, iova, iova_len);
+ iommu_dma_free_iova(cookie, iova, iova_len, NULL);
out_restore_sg:
__invalidate_sg(sg, nents);
return 0;
@@ -1194,7 +1208,7 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
return msi_page;

out_free_iova:
- iommu_dma_free_iova(cookie, iova, size);
+ iommu_dma_free_iova(cookie, iova, size, NULL);
out_free_page:
kfree(msi_page);
return NULL;
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 87b17bac04c2..63ee30c689a7 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1208,17 +1208,17 @@ static struct page *dma_pte_clear_level(struct dmar_domain *domain, int level,
pages can only be freed after the IOTLB flush has been done. */
static struct page *domain_unmap(struct dmar_domain *domain,
unsigned long start_pfn,
- unsigned long last_pfn)
+ unsigned long last_pfn,
+ struct page *freelist)
{
- struct page *freelist;
-
BUG_ON(!domain_pfn_supported(domain, start_pfn));
BUG_ON(!domain_pfn_supported(domain, last_pfn));
BUG_ON(start_pfn > last_pfn);

/* we don't need lock here; nobody else touches the iova range */
freelist = dma_pte_clear_level(domain, agaw_to_level(domain->agaw),
- domain->pgd, 0, start_pfn, last_pfn, NULL);
+ domain->pgd, 0, start_pfn, last_pfn,
+ freelist);

/* free pgd */
if (start_pfn == 0 && last_pfn == DOMAIN_MAX_PFN(domain->gaw)) {
@@ -1976,7 +1976,8 @@ static void domain_exit(struct dmar_domain *domain)
if (domain->pgd) {
struct page *freelist;

- freelist = domain_unmap(domain, 0, DOMAIN_MAX_PFN(domain->gaw));
+ freelist = domain_unmap(domain, 0,
+ DOMAIN_MAX_PFN(domain->gaw), NULL);
dma_free_pagelist(freelist);
}

@@ -3532,7 +3533,7 @@ static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size)
if (dev_is_pci(dev))
pdev = to_pci_dev(dev);

- freelist = domain_unmap(domain, start_pfn, last_pfn);
+ freelist = domain_unmap(domain, start_pfn, last_pfn, NULL);
if (intel_iommu_strict || (pdev && pdev->untrusted) ||
!has_iova_flush_queue(&domain->iovad)) {
iommu_flush_iotlb_psi(iommu, domain, start_pfn,
@@ -4595,7 +4596,8 @@ static int intel_iommu_memory_notifier(struct notifier_block *nb,
struct page *freelist;

freelist = domain_unmap(si_domain,
- start_vpfn, last_vpfn);
+ start_vpfn, last_vpfn,
+ NULL);

rcu_read_lock();
for_each_active_iommu(iommu, drhd)
@@ -5570,10 +5572,8 @@ static size_t intel_iommu_unmap(struct iommu_domain *domain,
struct iommu_iotlb_gather *gather)
{
struct dmar_domain *dmar_domain = to_dmar_domain(domain);
- struct page *freelist = NULL;
unsigned long start_pfn, last_pfn;
- unsigned int npages;
- int iommu_id, level = 0;
+ int level = 0;

/* Cope with horrid API which requires us to unmap more than the
size argument if it happens to be a large-page mapping. */
@@ -5585,22 +5585,38 @@ static size_t intel_iommu_unmap(struct iommu_domain *domain,
start_pfn = iova >> VTD_PAGE_SHIFT;
last_pfn = (iova + size - 1) >> VTD_PAGE_SHIFT;

- freelist = domain_unmap(dmar_domain, start_pfn, last_pfn);
-
- npages = last_pfn - start_pfn + 1;
-
- for_each_domain_iommu(iommu_id, dmar_domain)
- iommu_flush_iotlb_psi(g_iommus[iommu_id], dmar_domain,
- start_pfn, npages, !freelist, 0);
-
- dma_free_pagelist(freelist);
+ gather->freelist = domain_unmap(dmar_domain, start_pfn,
+ last_pfn, gather->freelist);

if (dmar_domain->max_addr == iova + size)
dmar_domain->max_addr = iova;

+ iommu_iotlb_gather_add_page(domain, gather, iova, size);
+
return size;
}

+static void intel_iommu_tlb_sync(struct iommu_domain *domain,
+ struct iommu_iotlb_gather *gather)
+{
+ struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+ unsigned long iova_pfn = IOVA_PFN(gather->start);
+ size_t size = gather->end - gather->start;
+ unsigned long start_pfn, last_pfn;
+ unsigned long nrpages;
+ int iommu_id;
+
+ nrpages = aligned_nrpages(gather->start, size);
+ start_pfn = mm_to_dma_pfn(iova_pfn);
+ last_pfn = start_pfn + nrpages - 1;
+
+ for_each_domain_iommu(iommu_id, dmar_domain)
+ iommu_flush_iotlb_psi(g_iommus[iommu_id], dmar_domain,
+ start_pfn, nrpages, !gather->freelist, 0);
+
+ dma_free_pagelist(gather->freelist);
+}
+
static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
dma_addr_t iova)
{
@@ -6060,6 +6076,7 @@ const struct iommu_ops intel_iommu_ops = {
.aux_get_pasid = intel_iommu_aux_get_pasid,
.map = intel_iommu_map,
.unmap = intel_iommu_unmap,
+ .iotlb_sync = intel_iommu_tlb_sync,
.iova_to_phys = intel_iommu_iova_to_phys,
.probe_device = intel_iommu_probe_device,
.probe_finalize = intel_iommu_probe_finalize,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index fee209efb756..f0d56360a976 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -180,6 +180,7 @@ struct iommu_iotlb_gather {
unsigned long start;
unsigned long end;
size_t pgsize;
+ struct page *freelist;
};

/**
--
2.17.1
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