From 707d561f77b5e2a6f90c9786bee44ee7a8dedc7e Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Mon, 7 Sep 2020 13:24:25 +0200 Subject: drm: allow limiting the scatter list size. Add drm_device argument to drm_prime_pages_to_sg(), so we can call dma_max_mapping_size() to figure the segment size limit and call into __sg_alloc_table_from_pages() with the correct limit. This fixes virtio-gpu with sev. Possibly it'll fix other bugs too given that drm seems to totaly ignore segment size limits so far ... v2: place max_segment in drm driver not gem object. v3: move max_segment next to the other gem fields. v4: just use dma_max_mapping_size(). Signed-off-by: Gerd Hoffmann Reviewed-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20200907112425.15610-2-kraxel@redhat.com --- drivers/gpu/drm/drm_prime.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'drivers/gpu/drm/drm_prime.c') diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 1693aa7c14b5..8a6a3c99b7d8 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -802,9 +802,11 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = { * * This is useful for implementing &drm_gem_object_funcs.get_sg_table. */ -struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int nr_pages) +struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev, + struct page **pages, unsigned int nr_pages) { struct sg_table *sg = NULL; + size_t max_segment = 0; int ret; sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL); @@ -813,8 +815,13 @@ struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int nr_page goto out; } - ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0, - nr_pages << PAGE_SHIFT, GFP_KERNEL); + if (dev) + max_segment = dma_max_mapping_size(dev->dev); + if (max_segment == 0 || max_segment > SCATTERLIST_MAX_SEGMENT) + max_segment = SCATTERLIST_MAX_SEGMENT; + ret = __sg_alloc_table_from_pages(sg, pages, nr_pages, 0, + nr_pages << PAGE_SHIFT, + max_segment, GFP_KERNEL); if (ret) goto out; -- cgit v1.2.3