6.6-stable review patch. If anyone has any objections, please let me know.
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From: Joao Martins joao.m.martins@oracle.com
[ Upstream commit 4bbcbc6ea2fa379632a24c14cfb47aa603816ac6 ]
For small bitmaps that aren't PAGE_SIZE aligned *and* that are less than 512 pages in bitmap length, use an extra page to be able to cover the entire range e.g. [1M..3G] which would be iterated more efficiently in a single iteration, rather than two.
Fixes: b058ea3ab5af ("vfio/iova_bitmap: refactor iova_bitmap_set() to better handle page boundaries") Link: https://lore.kernel.org/r/20240202133415.23819-10-joao.m.martins@oracle.com Signed-off-by: Joao Martins joao.m.martins@oracle.com Tested-by: Avihai Horon avihaih@nvidia.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/vfio/iova_bitmap.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/vfio/iova_bitmap.c b/drivers/vfio/iova_bitmap.c index 26ad0912cfea4..7af5b204990bb 100644 --- a/drivers/vfio/iova_bitmap.c +++ b/drivers/vfio/iova_bitmap.c @@ -175,18 +175,19 @@ static int iova_bitmap_get(struct iova_bitmap *bitmap) bitmap->mapped_base_index) * sizeof(*bitmap->bitmap), PAGE_SIZE);
- /* - * We always cap at max number of 'struct page' a base page can fit. - * This is, for example, on x86 means 2M of bitmap data max. - */ - npages = min(npages, PAGE_SIZE / sizeof(struct page *)); - /* * Bitmap address to be pinned is calculated via pointer arithmetic * with bitmap u64 word index. */ addr = bitmap->bitmap + bitmap->mapped_base_index;
+ /* + * We always cap at max number of 'struct page' a base page can fit. + * This is, for example, on x86 means 2M of bitmap data max. + */ + npages = min(npages + !!offset_in_page(addr), + PAGE_SIZE / sizeof(struct page *)); + ret = pin_user_pages_fast((unsigned long)addr, npages, FOLL_WRITE, mapped->pages); if (ret <= 0)