From patchwork Tue Jul 13 20:51:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Daniel Vetter X-Patchwork-Id: 12375025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7DCFCC07E96 for ; Tue, 13 Jul 2021 20:52:14 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 4C08761361 for ; Tue, 13 Jul 2021 20:52:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C08761361 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5B95F6E12E; Tue, 13 Jul 2021 20:52:04 +0000 (UTC) Received: from mail-wr1-x433.google.com (mail-wr1-x433.google.com [IPv6:2a00:1450:4864:20::433]) by gabe.freedesktop.org (Postfix) with ESMTPS id 78CCC89A08 for ; Tue, 13 Jul 2021 20:52:01 +0000 (UTC) Received: by mail-wr1-x433.google.com with SMTP id u1so411253wrs.1 for ; Tue, 13 Jul 2021 13:52:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=tb13L7U9dTCD6g70T53HTt4Zdsesm4ZnXBpaSFPW13w=; b=ZE05Y12a7V5jfYf3M4rfGrmXtIbZkpaEOKqRwBvqpdF6WVgvHYgmOlxZb0TrIWbDJg zJtba0xVTVEKWit7yauEX7Ll2j35Ys5tdQJsIFxi9ZsZiEHk2Byz55TIwiePzaPcddw0 2Q5Tyc2jB7dne2ntzJAvdaLzFnvt6NyLoLavw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=tb13L7U9dTCD6g70T53HTt4Zdsesm4ZnXBpaSFPW13w=; b=qbsTnSgu0edijF8n44+7GlVS3txAnPHDOx7uEPI71HZ5bmgs6J3V+fvAEsikDadfqO J1FbOxuRFAC6j6qBByBnIYIIoVz8VYpJD9NV+oWGHqVXy+rbr5K1OqbJ9IGp+EhRfu72 aGUiruNvweCxwgTI7B6ycCkOVMA1wnPy7CkjMdBc86XDaihAwftTzfU/CL+is/G2dPz2 wFhBXNA0poTimVOYX7CXxmMNjnHF2zWo0P/uJnsBYelICpRg7T62sQLS9VtIlzt2O+9f nXPejl/CSFlVdvq3jLbLHfOtk1/ziF+fECQ01ezDqPVM3+a8HHNrtVBwfiwySITiAA3L uTUg== X-Gm-Message-State: AOAM531ZA49pwrmW58B5dIz0X0j5eDxUzHqwGq7AuQdLBCce/CDgak3v 9Z1s/h6dyrVpNJWRJXQrmZiKWwno9/Ybaw== X-Google-Smtp-Source: ABdhPJxGX+4VmTvtDaSQVeWu7iGnr3LK8JR8WmSYlC0KYNHOE/Vk7imGwykovjH8SkAWboZLaVyy7Q== X-Received: by 2002:a5d:4e43:: with SMTP id r3mr8165252wrt.132.1626209520157; Tue, 13 Jul 2021 13:52:00 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id j10sm18642249wrt.35.2021.07.13.13.51.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Jul 2021 13:51:59 -0700 (PDT) From: Daniel Vetter To: Intel Graphics Development Date: Tue, 13 Jul 2021 22:51:50 +0200 Message-Id: <20210713205153.1896059-2-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210713205153.1896059-1-daniel.vetter@ffwll.ch> References: <20210713205153.1896059-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v4 1/4] dma-buf: Require VM_PFNMAP vma for mmap X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daniel Vetter , Matthew Wilcox , Sumit Semwal , linaro-mm-sig@lists.linaro.org, Jason Gunthorpe , John Stultz , DRI Development , Daniel Vetter , Suren Baghdasaryan , =?utf-8?q?Christian_K=C3=B6nig?= , linux-media@vger.kernel.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" tldr; DMA buffers aren't normal memory, expecting that you can use them like that (like calling get_user_pages works, or that they're accounting like any other normal memory) cannot be guaranteed. Since some userspace only runs on integrated devices, where all buffers are actually all resident system memory, there's a huge temptation to assume that a struct page is always present and useable like for any more pagecache backed mmap. This has the potential to result in a uapi nightmare. To stop this gap require that DMA buffer mmaps are VM_PFNMAP, which blocks get_user_pages and all the other struct page based infrastructure for everyone. In spirit this is the uapi counterpart to the kernel-internal CONFIG_DMABUF_DEBUG. Motivated by a recent patch which wanted to swich the system dma-buf heap to vm_insert_page instead of vm_insert_pfn. v2: Jason brought up that we also want to guarantee that all ptes have the pte_special flag set, to catch fast get_user_pages (on architectures that support this). Allowing VM_MIXEDMAP (like VM_SPECIAL does) would still allow vm_insert_page, but limiting to VM_PFNMAP will catch that. From auditing the various functions to insert pfn pte entires (vm_insert_pfn_prot, remap_pfn_range and all it's callers like dma_mmap_wc) it looks like VM_PFNMAP is already required anyway, so this should be the correct flag to check for. References: https://lore.kernel.org/lkml/CAKMK7uHi+mG0z0HUmNt13QCCvutuRVjpcR0NjRL12k-WbWzkRg@mail.gmail.com/ Acked-by: Christian König Cc: Jason Gunthorpe Cc: Suren Baghdasaryan Cc: Matthew Wilcox Cc: John Stultz Signed-off-by: Daniel Vetter Cc: Sumit Semwal Cc: "Christian König" Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Acked-by: Thomas Zimmermann --- Resending this so I can test the next two patches for vgem/shmem in intel-gfx-ci. Last round failed somehow, but I can't repro that at all locally here. No immediate plans to merge this patch here since ttm isn't addressed yet (and there we have the hugepte issue, for which I don't think we have a clear consensus yet). -Daniel --- drivers/dma-buf/dma-buf.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 510b42771974..65cbd7f0f16a 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -130,6 +130,7 @@ static struct file_system_type dma_buf_fs_type = { static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) { struct dma_buf *dmabuf; + int ret; if (!is_dma_buf_file(file)) return -EINVAL; @@ -145,7 +146,11 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) dmabuf->size >> PAGE_SHIFT) return -EINVAL; - return dmabuf->ops->mmap(dmabuf, vma); + ret = dmabuf->ops->mmap(dmabuf, vma); + + WARN_ON(!(vma->vm_flags & VM_PFNMAP)); + + return ret; } static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence) @@ -1276,6 +1281,8 @@ EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, unsigned long pgoff) { + int ret; + if (WARN_ON(!dmabuf || !vma)) return -EINVAL; @@ -1296,7 +1303,11 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, vma_set_file(vma, dmabuf->file); vma->vm_pgoff = pgoff; - return dmabuf->ops->mmap(dmabuf, vma); + ret = dmabuf->ops->mmap(dmabuf, vma); + + WARN_ON(!(vma->vm_flags & VM_PFNMAP)); + + return ret; } EXPORT_SYMBOL_GPL(dma_buf_mmap);