From patchwork Sun Feb 25 07:57:01 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kasireddy, Vivek" X-Patchwork-Id: 13570764 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CEF74C54798 for ; Sun, 25 Feb 2024 08:24:22 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B28B110E169; Sun, 25 Feb 2024 08:24:14 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="cMYJOgvQ"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.17]) by gabe.freedesktop.org (Postfix) with ESMTPS id CC78310E252 for ; Sun, 25 Feb 2024 08:24:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1708849454; x=1740385454; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=OFY0cfHR/dm9OGHwjR/w6MaeqHarFwrIQpExmOosGtk=; b=cMYJOgvQDW8bxqat9Wp1DMhPigbXdgQoISUepjUPX0h2SUmykZt6z2BJ GdQmiwP2YfKy2M/4LTJWq9wSXWm7Y0PlAaAh9vjRFgT84qAHhBJ1/wRfI 42YVdAETlq5tBwIAZhvXC7/HaF7gBJvrp7ZEKDYxS1wdPxvHmWVKDKZqi bnTu/hD2yLk5UZPmYLFKJXPxGhZnc67k2X3qGmUWukVXVI5OLxCQAicWB qKKByLYL7FHJxv3VpX6SXPgIbuwAtn5iEorZlPtGdXSL+JraEkZ1QOWOc 3e3gRbJW5V7ve5x3b/ygxUVnIeGZy7iV9Jh1xykku7ZQawJkU5K733LRh g==; X-IronPort-AV: E=McAfee;i="6600,9927,10994"; a="2988379" X-IronPort-AV: E=Sophos;i="6.06,183,1705392000"; d="scan'208";a="2988379" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by fmvoesa111.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Feb 2024 00:24:13 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.06,183,1705392000"; d="scan'208";a="6783260" Received: from vkasired-desk2.fm.intel.com ([10.105.128.132]) by orviesa006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Feb 2024 00:24:13 -0800 From: Vivek Kasireddy To: dri-devel@lists.freedesktop.org, linux-mm@kvack.org Cc: Vivek Kasireddy , David Hildenbrand , Daniel Vetter , Mike Kravetz , Hugh Dickins , Peter Xu , Jason Gunthorpe , Gerd Hoffmann , Dongwon Kim , Junxiao Chang Subject: [PATCH v12 5/8] udmabuf: Add back support for mapping hugetlb pages Date: Sat, 24 Feb 2024 23:57:01 -0800 Message-ID: <20240225080008.1019653-6-vivek.kasireddy@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240225080008.1019653-1-vivek.kasireddy@intel.com> References: <20240225080008.1019653-1-vivek.kasireddy@intel.com> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" A user or admin can configure a VMM (Qemu) Guest's memory to be backed by hugetlb pages for various reasons. However, a Guest OS would still allocate (and pin) buffers that are backed by regular 4k sized pages. In order to map these buffers and create dma-bufs for them on the Host, we first need to find the hugetlb pages where the buffer allocations are located and then determine the offsets of individual chunks (within those pages) and use this information to eventually populate a scatterlist. Testcase: default_hugepagesz=2M hugepagesz=2M hugepages=2500 options were passed to the Host kernel and Qemu was launched with these relevant options: qemu-system-x86_64 -m 4096m.... -device virtio-gpu-pci,max_outputs=1,blob=true,xres=1920,yres=1080 -display gtk,gl=on -object memory-backend-memfd,hugetlb=on,id=mem1,size=4096M -machine memory-backend=mem1 Replacing -display gtk,gl=on with -display gtk,gl=off above would exercise the mmap handler. Cc: David Hildenbrand Cc: Daniel Vetter Cc: Mike Kravetz Cc: Hugh Dickins Cc: Peter Xu Cc: Jason Gunthorpe Cc: Gerd Hoffmann Cc: Dongwon Kim Cc: Junxiao Chang Acked-by: Mike Kravetz (v2) Signed-off-by: Vivek Kasireddy --- drivers/dma-buf/udmabuf.c | 122 +++++++++++++++++++++++++++++++------- 1 file changed, 101 insertions(+), 21 deletions(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index 820c993c8659..274defd3fa3e 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -28,6 +29,7 @@ struct udmabuf { struct page **pages; struct sg_table *sg; struct miscdevice *device; + pgoff_t *offsets; }; static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf) @@ -41,6 +43,8 @@ static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf) return VM_FAULT_SIGBUS; pfn = page_to_pfn(ubuf->pages[pgoff]); + pfn += ubuf->offsets[pgoff] >> PAGE_SHIFT; + return vmf_insert_pfn(vma, vmf->address, pfn); } @@ -90,23 +94,29 @@ static struct sg_table *get_sg_table(struct device *dev, struct dma_buf *buf, { struct udmabuf *ubuf = buf->priv; struct sg_table *sg; + struct scatterlist *sgl; + unsigned int i = 0; int ret; sg = kzalloc(sizeof(*sg), GFP_KERNEL); if (!sg) return ERR_PTR(-ENOMEM); - ret = sg_alloc_table_from_pages(sg, ubuf->pages, ubuf->pagecount, - 0, ubuf->pagecount << PAGE_SHIFT, - GFP_KERNEL); + + ret = sg_alloc_table(sg, ubuf->pagecount, GFP_KERNEL); if (ret < 0) - goto err; + goto err_alloc; + + for_each_sg(sg->sgl, sgl, ubuf->pagecount, i) + sg_set_page(sgl, ubuf->pages[i], PAGE_SIZE, ubuf->offsets[i]); + ret = dma_map_sgtable(dev, sg, direction, 0); if (ret < 0) - goto err; + goto err_map; return sg; -err: +err_map: sg_free_table(sg); +err_alloc: kfree(sg); return ERR_PTR(ret); } @@ -143,6 +153,7 @@ static void release_udmabuf(struct dma_buf *buf) for (pg = 0; pg < ubuf->pagecount; pg++) put_page(ubuf->pages[pg]); + kfree(ubuf->offsets); kfree(ubuf->pages); kfree(ubuf); } @@ -196,17 +207,77 @@ static const struct dma_buf_ops udmabuf_ops = { #define SEALS_WANTED (F_SEAL_SHRINK) #define SEALS_DENIED (F_SEAL_WRITE) +static int handle_hugetlb_pages(struct udmabuf *ubuf, struct file *memfd, + pgoff_t offset, pgoff_t pgcnt, + pgoff_t *pgbuf) +{ + struct hstate *hpstate = hstate_file(memfd); + pgoff_t mapidx = offset >> huge_page_shift(hpstate); + pgoff_t subpgoff = (offset & ~huge_page_mask(hpstate)) >> PAGE_SHIFT; + pgoff_t maxsubpgs = huge_page_size(hpstate) >> PAGE_SHIFT; + struct page *hpage = NULL; + struct folio *folio; + pgoff_t pgidx; + + mapidx <<= huge_page_order(hpstate); + for (pgidx = 0; pgidx < pgcnt; pgidx++) { + if (!hpage) { + folio = __filemap_get_folio(memfd->f_mapping, + mapidx, + FGP_ACCESSED, 0); + if (IS_ERR(folio)) + return PTR_ERR(folio); + + hpage = &folio->page; + } + + get_page(hpage); + ubuf->pages[*pgbuf] = hpage; + ubuf->offsets[*pgbuf] = subpgoff << PAGE_SHIFT; + (*pgbuf)++; + if (++subpgoff == maxsubpgs) { + put_page(hpage); + hpage = NULL; + subpgoff = 0; + mapidx += pages_per_huge_page(hpstate); + } + } + + if (hpage) + put_page(hpage); + + return 0; +} + +static int handle_shmem_pages(struct udmabuf *ubuf, struct file *memfd, + pgoff_t offset, pgoff_t pgcnt, + pgoff_t *pgbuf) +{ + pgoff_t pgidx, pgoff = offset >> PAGE_SHIFT; + struct page *page; + + for (pgidx = 0; pgidx < pgcnt; pgidx++) { + page = shmem_read_mapping_page(memfd->f_mapping, + pgoff + pgidx); + if (IS_ERR(page)) + return PTR_ERR(page); + + ubuf->pages[*pgbuf] = page; + (*pgbuf)++; + } + + return 0; +} + static long udmabuf_create(struct miscdevice *device, struct udmabuf_create_list *head, struct udmabuf_create_item *list) { DEFINE_DMA_BUF_EXPORT_INFO(exp_info); struct file *memfd = NULL; - struct address_space *mapping = NULL; struct udmabuf *ubuf; struct dma_buf *buf; - pgoff_t pgoff, pgcnt, pgidx, pgbuf = 0, pglimit; - struct page *page; + pgoff_t pgcnt, pgbuf = 0, pglimit; int seals, ret = -EINVAL; u32 i, flags; @@ -234,6 +305,12 @@ static long udmabuf_create(struct miscdevice *device, ret = -ENOMEM; goto err; } + ubuf->offsets = kcalloc(ubuf->pagecount, sizeof(*ubuf->offsets), + GFP_KERNEL); + if (!ubuf->offsets) { + ret = -ENOMEM; + goto err; + } pgbuf = 0; for (i = 0; i < head->count; i++) { @@ -241,8 +318,7 @@ static long udmabuf_create(struct miscdevice *device, memfd = fget(list[i].memfd); if (!memfd) goto err; - mapping = memfd->f_mapping; - if (!shmem_mapping(mapping)) + if (!shmem_file(memfd) && !is_file_hugepages(memfd)) goto err; seals = memfd_fcntl(memfd, F_GET_SEALS, 0); if (seals == -EINVAL) @@ -251,16 +327,19 @@ static long udmabuf_create(struct miscdevice *device, if ((seals & SEALS_WANTED) != SEALS_WANTED || (seals & SEALS_DENIED) != 0) goto err; - pgoff = list[i].offset >> PAGE_SHIFT; - pgcnt = list[i].size >> PAGE_SHIFT; - for (pgidx = 0; pgidx < pgcnt; pgidx++) { - page = shmem_read_mapping_page(mapping, pgoff + pgidx); - if (IS_ERR(page)) { - ret = PTR_ERR(page); - goto err; - } - ubuf->pages[pgbuf++] = page; - } + + pgcnt = list[i].size >> PAGE_SHIFT; + if (is_file_hugepages(memfd)) + ret = handle_hugetlb_pages(ubuf, memfd, + list[i].offset, + pgcnt, &pgbuf); + else + ret = handle_shmem_pages(ubuf, memfd, + list[i].offset, + pgcnt, &pgbuf); + if (ret < 0) + goto err; + fput(memfd); memfd = NULL; } @@ -287,6 +366,7 @@ static long udmabuf_create(struct miscdevice *device, put_page(ubuf->pages[--pgbuf]); if (memfd) fput(memfd); + kfree(ubuf->offsets); kfree(ubuf->pages); kfree(ubuf); return ret;