From mboxrd@z Thu Jan 1 00:00:00 1970 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 9B223C432BE for ; Fri, 23 Jul 2021 11:35:06 +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 66ACE60E75 for ; Fri, 23 Jul 2021 11:35:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 66ACE60E75 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5CB9D6FABF; Fri, 23 Jul 2021 11:35:04 +0000 (UTC) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3E4F66F62A; Fri, 23 Jul 2021 11:35:02 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10053"; a="209969515" X-IronPort-AV: E=Sophos;i="5.84,263,1620716400"; d="scan'208";a="209969515" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jul 2021 04:35:01 -0700 X-IronPort-AV: E=Sophos;i="5.84,263,1620716400"; d="scan'208";a="471277641" Received: from rorykav-mobl.ger.corp.intel.com (HELO mwauld-desk1.intel.com) ([10.213.196.197]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jul 2021 04:34:58 -0700 From: Matthew Auld To: intel-gfx@lists.freedesktop.org Subject: [PATCH] drm/i915/userptr: Probe existence of backing struct pages upon creation Date: Fri, 23 Jul 2021 12:34:05 +0100 Message-Id: <20210723113405.427004-1-matthew.auld@intel.com> X-Mailer: git-send-email 2.26.3 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: , Cc: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , Tvrtko Ursulin , Jordan Justen , Tvrtko Ursulin , dri-devel@lists.freedesktop.org, Chris Wilson , Kenneth Graunke , Jason Ekstrand , Daniel Vetter Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Chris Wilson Jason Ekstrand requested a more efficient method than userptr+set-domain to determine if the userptr object was backed by a complete set of pages upon creation. To be more efficient than simply populating the userptr using get_user_pages() (as done by the call to set-domain or execbuf), we can walk the tree of vm_area_struct and check for gaps or vma not backed by struct page (VM_PFNMAP). The question is how to handle VM_MIXEDMAP which may be either struct page or pfn backed... With discrete we are going to drop support for set_domain(), so offering a way to probe the pages, without having to resort to dummy batches has been requested. v2: - add new query param for the PROBE flag, so userspace can easily check if the kernel supports it(Jason). - use mmap_read_{lock, unlock}. - add some kernel-doc. v3: - In the docs also mention that PROBE doesn't guarantee that the pages will remain valid by the time they are actually used(Tvrtko). - Add a small comment for the hole finding logic(Jason). - Move the param next to all the other params which just return true. Testcase: igt/gem_userptr_blits/probe Signed-off-by: Chris Wilson Signed-off-by: Matthew Auld Cc: Thomas Hellström Cc: Maarten Lankhorst Cc: Tvrtko Ursulin Cc: Jordan Justen Cc: Kenneth Graunke Cc: Jason Ekstrand Cc: Daniel Vetter Cc: Ramalingam C Reviewed-by: Tvrtko Ursulin Acked-by: Kenneth Graunke Reviewed-by: Jason Ekstrand --- drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 41 ++++++++++++++++++++- drivers/gpu/drm/i915/i915_getparam.c | 1 + include/uapi/drm/i915_drm.h | 20 ++++++++++ 3 files changed, 61 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c index 56edfeff8c02..468a7a617fbf 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c @@ -422,6 +422,34 @@ static const struct drm_i915_gem_object_ops i915_gem_userptr_ops = { #endif +static int +probe_range(struct mm_struct *mm, unsigned long addr, unsigned long len) +{ + const unsigned long end = addr + len; + struct vm_area_struct *vma; + int ret = -EFAULT; + + mmap_read_lock(mm); + for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) { + /* Check for holes, note that we also update the addr below */ + if (vma->vm_start > addr) + break; + + if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) + break; + + if (vma->vm_end >= end) { + ret = 0; + break; + } + + addr = vma->vm_end; + } + mmap_read_unlock(mm); + + return ret; +} + /* * Creates a new mm object that wraps some normal memory from the process * context - user memory. @@ -477,7 +505,8 @@ i915_gem_userptr_ioctl(struct drm_device *dev, } if (args->flags & ~(I915_USERPTR_READ_ONLY | - I915_USERPTR_UNSYNCHRONIZED)) + I915_USERPTR_UNSYNCHRONIZED | + I915_USERPTR_PROBE)) return -EINVAL; if (i915_gem_object_size_2big(args->user_size)) @@ -504,6 +533,16 @@ i915_gem_userptr_ioctl(struct drm_device *dev, return -ENODEV; } + if (args->flags & I915_USERPTR_PROBE) { + /* + * Check that the range pointed to represents real struct + * pages and not iomappings (at this moment in time!) + */ + ret = probe_range(current->mm, args->user_ptr, args->user_size); + if (ret) + return ret; + } + #ifdef CONFIG_MMU_NOTIFIER obj = i915_gem_object_alloc(); if (obj == NULL) diff --git a/drivers/gpu/drm/i915/i915_getparam.c b/drivers/gpu/drm/i915/i915_getparam.c index 24e18219eb50..bbb7cac43eb4 100644 --- a/drivers/gpu/drm/i915/i915_getparam.c +++ b/drivers/gpu/drm/i915/i915_getparam.c @@ -134,6 +134,7 @@ int i915_getparam_ioctl(struct drm_device *dev, void *data, case I915_PARAM_HAS_EXEC_FENCE_ARRAY: case I915_PARAM_HAS_EXEC_SUBMIT_FENCE: case I915_PARAM_HAS_EXEC_TIMELINE_FENCES: + case I915_PARAM_HAS_USERPTR_PROBE: /* For the time being all of these are always true; * if some supported hardware does not have one of these * features this value needs to be provided from diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index 975087553ea0..0d290535a6e5 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -674,6 +674,9 @@ typedef struct drm_i915_irq_wait { */ #define I915_PARAM_HAS_EXEC_TIMELINE_FENCES 55 +/* Query if the kernel supports the I915_USERPTR_PROBE flag. */ +#define I915_PARAM_HAS_USERPTR_PROBE 56 + /* Must be kept compact -- no holes and well documented */ typedef struct drm_i915_getparam { @@ -2222,12 +2225,29 @@ struct drm_i915_gem_userptr { * through the GTT. If the HW can't support readonly access, an error is * returned. * + * I915_USERPTR_PROBE: + * + * Probe the provided @user_ptr range and validate that the @user_ptr is + * indeed pointing to normal memory and that the range is also valid. + * For example if some garbage address is given to the kernel, then this + * should complain. + * + * Returns -EFAULT if the probe failed. + * + * Note that this doesn't populate the backing pages, and also doesn't + * guarantee that the object will remain valid when the object is + * eventually used. + * + * The kernel supports this feature if I915_PARAM_HAS_USERPTR_PROBE + * returns a non-zero value. + * * I915_USERPTR_UNSYNCHRONIZED: * * NOT USED. Setting this flag will result in an error. */ __u32 flags; #define I915_USERPTR_READ_ONLY 0x1 +#define I915_USERPTR_PROBE 0x2 #define I915_USERPTR_UNSYNCHRONIZED 0x80000000 /** * @handle: Returned handle for the object. -- 2.26.3