From patchwork Mon Jun 24 06:36:14 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kasireddy, Vivek" X-Patchwork-Id: 13709055 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 3852EC2BD05 for ; Mon, 24 Jun 2024 07:05:39 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D3FED10E368; Mon, 24 Jun 2024 07:05:37 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="Ybl10/Lx"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.21]) by gabe.freedesktop.org (Postfix) with ESMTPS id 67A6210E362 for ; Mon, 24 Jun 2024 07:05:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1719212726; x=1750748726; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=KWfvKYp6qtQmdJwHokBW0M3ksxOQNq0tWLBPfJBLXlM=; b=Ybl10/LxPDC+pCJ/oDLtMgOv5Krr4wKS+FPWYBSaPR8fO9LO/cUeBhhq cLOhWTXHX5G5V+YcRxs1Emn7QCZRXly6TGqBJvHY0EgEeTxSOvZTEAC97 zVdWzhCebt5DG4EBVPvswD2bTPZO0fhsxjYgLmNSvoX95djN7UYIZlUYQ XZdHLBpVRzuP8TR9uYeDFEEBvtJgYl2qqsLFPjjVhILpUHBbcCLtv+wFU LlRuZ/DF2AuqQgClumkAb0ZXJ6K1pmPMUbMIqxpnFDiVVg7vQhCq6wA9V GI+iECHf4EDhLmrhYHa6FNn9jP2NlkRz5Kf0gYEqBKDqe2bOsN1guHVqI Q==; X-CSE-ConnectionGUID: reU037XITsichqdnzMuQTQ== X-CSE-MsgGUID: rOhfYyjHQ9Ctnx1tgpxsMg== X-IronPort-AV: E=McAfee;i="6700,10204,11112"; a="16134965" X-IronPort-AV: E=Sophos;i="6.08,261,1712646000"; d="scan'208";a="16134965" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by orvoesa113.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2024 00:05:26 -0700 X-CSE-ConnectionGUID: ytc2l21XQmWELk9WFFK/Dw== X-CSE-MsgGUID: jiNoum31R2yQInzB0kiDZw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,261,1712646000"; d="scan'208";a="73955882" Received: from vkasired-desk2.fm.intel.com ([10.105.128.132]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2024 00:05:25 -0700 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 , Dave Airlie Subject: [PATCH v16 6/9] udmabuf: Add back support for mapping hugetlb pages Date: Sun, 23 Jun 2024 23:36:14 -0700 Message-ID: <20240624063952.1572359-7-vivek.kasireddy@intel.com> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240624063952.1572359-1-vivek.kasireddy@intel.com> References: <20240624063952.1572359-1-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) Acked-by: Dave Airlie Acked-by: Gerd Hoffmann 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;