[RFC 4/7] iommu/dma-iommu: Handle freelists in the dma-iommu api path

Tom Murphy
2019-05-04T13:23:20Z

Currently the iova flush queue implementation in the dma-iommu api path
doesn't handle freelists. Change the unmap_fast code to allow it to
return any freelists which need to be handled.

Signed-off-by: Tom Murphy <tmurphy@arista.com>
---
drivers/iommu/dma-iommu.c | 39 +++++++++++++++++++++++----------
drivers/iommu/iommu.c | 10 +++++----
drivers/vfio/vfio_iommu_type1.c | 2 +-
include/linux/iommu.h | 3 ++-
4 files changed, 36 insertions(+), 18 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index fa5713a4f6f8..82ba500886b4 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -49,6 +49,18 @@ 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 != NULL) {
+ 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)
@@ -313,7 +325,8 @@ 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)
@@ -393,7 +406,7 @@ 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;

@@ -402,7 +415,8 @@ 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));
@@ -414,14 +428,15 @@ static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t dma_addr,
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iova_domain *iovad = &cookie->iovad;
size_t iova_off = iova_offset(iovad, dma_addr);
+ struct page *freelist;

dma_addr -= iova_off;
size = iova_align(iovad, size + iova_off);

- WARN_ON(iommu_unmap_fast(domain, dma_addr, size) != size);
+ WARN_ON(iommu_unmap_fast(domain, dma_addr, size, &freelist) != size);
if (!cookie->fq_domain)
- iommu_tlb_sync(domain);
- iommu_dma_free_iova(cookie, dma_addr, size);
+ iommu_flush_iotlb_range(domain, dma_addr, size, freelist);
+ iommu_dma_free_iova(cookie, dma_addr, size, freelist);
}

static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
@@ -441,7 +456,7 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
return DMA_MAPPING_ERROR;

if (iommu_map(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;
@@ -600,7 +615,7 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
struct iova_domain *iovad = &cookie->iovad;
bool coherent = dev_is_dma_coherent(dev);
int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
- pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
+ pgprot_t prot = pgprot_noncached(PAGE_KERNEL);
unsigned int count, min_size, alloc_sizes = domain->pgsize_bitmap;
struct page **pages;
struct sg_table sgt;
@@ -659,7 +674,7 @@ 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;
@@ -668,7 +683,7 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
static void *iommu_dma_alloc_contiguous_remap(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
- pgprot_t prot = arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs);
+ pgprot_t prot = pgprot_noncached(PAGE_KERNEL);
struct page *page;
void *addr;

@@ -1009,7 +1024,7 @@ 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;
@@ -1115,7 +1130,7 @@ static int iommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,
unsigned long pfn;
int ret;

- vma->vm_page_prot = arch_dma_mmap_pgprot(dev, vma->vm_page_prot, attrs);
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
return ret;
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 23918e7a0094..c7a7d9adb753 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1654,7 +1654,7 @@ EXPORT_SYMBOL_GPL(iommu_map);

static size_t __iommu_unmap(struct iommu_domain *domain,
unsigned long iova, size_t size,
- bool sync)
+ bool sync, struct page **freelist)
{
const struct iommu_ops *ops = domain->ops;
size_t unmapped_page, unmapped = 0;
@@ -1710,6 +1710,8 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
if (sync && ops->flush_iotlb_range)
ops->flush_iotlb_range(domain, orig_iova, unmapped,
freelist_head);
+ else if (freelist)
+ *freelist = freelist_head;

trace_unmap(orig_iova, size, unmapped);
return unmapped;
@@ -1718,14 +1720,14 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
size_t iommu_unmap(struct iommu_domain *domain,
unsigned long iova, size_t size)
{
- return __iommu_unmap(domain, iova, size, true);
+ return __iommu_unmap(domain, iova, size, true, NULL);
}
EXPORT_SYMBOL_GPL(iommu_unmap);

size_t iommu_unmap_fast(struct iommu_domain *domain,
- unsigned long iova, size_t size)
+ unsigned long iova, size_t size, struct page **freelist)
{
- return __iommu_unmap(domain, iova, size, false);
+ return __iommu_unmap(domain, iova, size, false, freelist);
}
EXPORT_SYMBOL_GPL(iommu_unmap_fast);

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 26c3f519b01a..5f58fcb1c2e1 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -710,7 +710,7 @@ static size_t unmap_unpin_fast(struct vfio_domain *domain,
struct vfio_regions *entry = kzalloc(sizeof(*entry), GFP_KERNEL);

if (entry) {
- unmapped = iommu_unmap_fast(domain->domain, *iova, len);
+ unmapped = iommu_unmap_fast(domain->domain, *iova, len, NULL);

if (!unmapped) {
kfree(entry);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 7e084eb1725f..f472cfee1c8c 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -310,7 +310,8 @@ extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
size_t size);
extern size_t iommu_unmap_fast(struct iommu_domain *domain,
- unsigned long iova, size_t size);
+ unsigned long iova, size_t size,
+ struct page **freelist);
extern size_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
struct scatterlist *sg,unsigned int nents, int prot);
extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova);
--
2.17.1