This is a note to let you know that I've just added the patch titled
vfio/type1: Prepare for batched pinning with struct vfio_batch
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vfio-type1-prepare-for-batched-pinning-with-struct-v.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 50a5be8af5e4cad083f350e90abe6477bc28a963
Author: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Date: Fri Feb 19 11:13:04 2021 -0500
vfio/type1: Prepare for batched pinning with struct vfio_batch
[ Upstream commit 4b6c33b3229678e38a6b0bbd4367d4b91366b523 ]
Get ready to pin more pages at once with struct vfio_batch, which
represents a batch of pinned pages.
The struct has a fallback page pointer to avoid two unlikely scenarios:
pointlessly allocating a page if disable_hugepages is enabled or failing
the whole pinning operation if the kernel can't allocate memory.
vaddr_get_pfn() becomes vaddr_get_pfns() to prepare for handling
multiple pages, though for now only one page is stored in the pages
array.
Signed-off-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
Stable-dep-of: 873aefb376bb ("vfio/type1: Unpin zero pages")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 2d26244f9c32..0c15cffd5ef1 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -98,6 +98,12 @@ struct vfio_dma {
unsigned long *bitmap;
};
+struct vfio_batch {
+ struct page **pages; /* for pin_user_pages_remote */
+ struct page *fallback_page; /* if pages alloc fails */
+ int capacity; /* length of pages array */
+};
+
struct vfio_group {
struct iommu_group *iommu_group;
struct list_head next;
@@ -428,6 +434,31 @@ static int put_pfn(unsigned long pfn, int prot)
return 0;
}
+#define VFIO_BATCH_MAX_CAPACITY (PAGE_SIZE / sizeof(struct page *))
+
+static void vfio_batch_init(struct vfio_batch *batch)
+{
+ if (unlikely(disable_hugepages))
+ goto fallback;
+
+ batch->pages = (struct page **) __get_free_page(GFP_KERNEL);
+ if (!batch->pages)
+ goto fallback;
+
+ batch->capacity = VFIO_BATCH_MAX_CAPACITY;
+ return;
+
+fallback:
+ batch->pages = &batch->fallback_page;
+ batch->capacity = 1;
+}
+
+static void vfio_batch_fini(struct vfio_batch *batch)
+{
+ if (batch->capacity == VFIO_BATCH_MAX_CAPACITY)
+ free_page((unsigned long)batch->pages);
+}
+
static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm,
unsigned long vaddr, unsigned long *pfn,
bool write_fault)
@@ -468,10 +499,10 @@ static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm,
* Returns the positive number of pfns successfully obtained or a negative
* error code.
*/
-static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
- int prot, unsigned long *pfn)
+static int vaddr_get_pfns(struct mm_struct *mm, unsigned long vaddr,
+ long npages, int prot, unsigned long *pfn,
+ struct page **pages)
{
- struct page *page[1];
struct vm_area_struct *vma;
unsigned int flags = 0;
int ret;
@@ -480,10 +511,10 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
flags |= FOLL_WRITE;
mmap_read_lock(mm);
- ret = pin_user_pages_remote(mm, vaddr, 1, flags | FOLL_LONGTERM,
- page, NULL, NULL);
- if (ret == 1) {
- *pfn = page_to_pfn(page[0]);
+ ret = pin_user_pages_remote(mm, vaddr, npages, flags | FOLL_LONGTERM,
+ pages, NULL, NULL);
+ if (ret > 0) {
+ *pfn = page_to_pfn(pages[0]);
goto done;
}
@@ -516,7 +547,7 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
*/
static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
long npage, unsigned long *pfn_base,
- unsigned long limit)
+ unsigned long limit, struct vfio_batch *batch)
{
unsigned long pfn = 0;
long ret, pinned = 0, lock_acct = 0;
@@ -527,7 +558,8 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
if (!current->mm)
return -ENODEV;
- ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, pfn_base);
+ ret = vaddr_get_pfns(current->mm, vaddr, 1, dma->prot, pfn_base,
+ batch->pages);
if (ret < 0)
return ret;
@@ -554,7 +586,8 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
/* Lock all the consecutive pages from pfn_base */
for (vaddr += PAGE_SIZE, iova += PAGE_SIZE; pinned < npage;
pinned++, vaddr += PAGE_SIZE, iova += PAGE_SIZE) {
- ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, &pfn);
+ ret = vaddr_get_pfns(current->mm, vaddr, 1, dma->prot, &pfn,
+ batch->pages);
if (ret < 0)
break;
@@ -617,6 +650,7 @@ static long vfio_unpin_pages_remote(struct vfio_dma *dma, dma_addr_t iova,
static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr,
unsigned long *pfn_base, bool do_accounting)
{
+ struct page *pages[1];
struct mm_struct *mm;
int ret;
@@ -624,7 +658,7 @@ static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr,
if (!mm)
return -ENODEV;
- ret = vaddr_get_pfn(mm, vaddr, dma->prot, pfn_base);
+ ret = vaddr_get_pfns(mm, vaddr, 1, dma->prot, pfn_base, pages);
if (ret == 1 && do_accounting && !is_invalid_reserved_pfn(*pfn_base)) {
ret = vfio_lock_acct(dma, 1, true);
if (ret) {
@@ -1270,15 +1304,19 @@ static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma,
{
dma_addr_t iova = dma->iova;
unsigned long vaddr = dma->vaddr;
+ struct vfio_batch batch;
size_t size = map_size;
long npage;
unsigned long pfn, limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
int ret = 0;
+ vfio_batch_init(&batch);
+
while (size) {
/* Pin a contiguous chunk of memory */
npage = vfio_pin_pages_remote(dma, vaddr + dma->size,
- size >> PAGE_SHIFT, &pfn, limit);
+ size >> PAGE_SHIFT, &pfn, limit,
+ &batch);
if (npage <= 0) {
WARN_ON(!npage);
ret = (int)npage;
@@ -1298,6 +1336,7 @@ static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma,
dma->size += npage << PAGE_SHIFT;
}
+ vfio_batch_fini(&batch);
dma->iommu_mapped = true;
if (ret)
@@ -1456,6 +1495,7 @@ static int vfio_bus_type(struct device *dev, void *data)
static int vfio_iommu_replay(struct vfio_iommu *iommu,
struct vfio_domain *domain)
{
+ struct vfio_batch batch;
struct vfio_domain *d = NULL;
struct rb_node *n;
unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
@@ -1466,6 +1506,8 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu,
d = list_first_entry(&iommu->domain_list,
struct vfio_domain, next);
+ vfio_batch_init(&batch);
+
n = rb_first(&iommu->dma_list);
for (; n; n = rb_next(n)) {
@@ -1513,7 +1555,8 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu,
npage = vfio_pin_pages_remote(dma, vaddr,
n >> PAGE_SHIFT,
- &pfn, limit);
+ &pfn, limit,
+ &batch);
if (npage <= 0) {
WARN_ON(!npage);
ret = (int)npage;
@@ -1546,6 +1589,7 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu,
dma->iommu_mapped = true;
}
+ vfio_batch_fini(&batch);
return 0;
unwind:
@@ -1586,6 +1630,7 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu,
}
}
+ vfio_batch_fini(&batch);
return ret;
}
