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=-13.6 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,URIBL_BLOCKED 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 DC2E6C432BE for ; Fri, 23 Jul 2021 17:48:11 +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 A914F60C51 for ; Fri, 23 Jul 2021 17:48:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A914F60C51 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=jlekstrand.net 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 579186F9E7; Fri, 23 Jul 2021 17:48:10 +0000 (UTC) Received: from mail-yb1-xb2e.google.com (mail-yb1-xb2e.google.com [IPv6:2607:f8b0:4864:20::b2e]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2AD346F9DD for ; Fri, 23 Jul 2021 17:48:09 +0000 (UTC) Received: by mail-yb1-xb2e.google.com with SMTP id z18so3507109ybg.8 for ; Fri, 23 Jul 2021 10:48:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=jlekstrand-net.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=o/R6Aa/nrNSrQK0OadKko9FGpwjJc4dzlZwULHZXrLE=; b=yAZZqMd90mNDlsH9edJqy/ffgfbfJ3o3ZkXfHHsEQ4E0whFSrYKaOpYDBjFgwNXR9+ 34SpNA4TvO3qbt3zMaAQiU0uVvef9YGSGz01YYo8eympProoHZaGym9JmQYVd0W3khRt G0hiQ5snRmIJ3lTlI82JfKV0isxgT1rTz68x63m2EnIOaiXFoNOnWsVek0JSCnCPgfIE JGrpP/nLLZjvDaYmqj+Wc8tU5ebBHzYpV/dNUEqpJQaliUyz+75f1GI+JDYz8Gr3yT6q YndEjkPHGoboRI9Sk+8F2E/lEMcFDyEWZj0u69Y6LeKYwXGVnkqUYQ4gBj7hW6Qg7IxJ thNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=o/R6Aa/nrNSrQK0OadKko9FGpwjJc4dzlZwULHZXrLE=; b=bO1qk2FG7P2+my+ccdJJOHxEj7zbvEyQB4OpGFXGBxpSdNHfsIpyZimjiICd6A1X/L JkQyLbS64anloVvk5DOzDHImNUnwgXeauMsYTZHBAGkAhcxntPNlQm0unZKVtF4FTb9A kL5DlwNnmzVpDjGd67uGz4NBIe2VoSr+SmJEcxIhd0En9IP+Wg4B1I0jhM698Gfbfcqk GItR/GEwxUkfQHAfkzYnuHZha1B/P++Fd7JdBrCIsZYPenPN8p8b/MYhjVdGzwztWkN+ GWtLh+wWte8zBNQqS2hXUtT3ekX8lrWR0flUIdsLN7O2X7UAT8tdZ4XaiZQWKNhZ5+h9 TCdQ== X-Gm-Message-State: AOAM533WDtx//VyFJoZBdboF1AdIEBoImMvI6kRhPGh0sUKZ0CfJrZp3 dF911rAHXn8tuuYIE/NIpoucsxPQj9Xr8YFjKtqbOQ== X-Google-Smtp-Source: ABdhPJz3NMApVRcPjEjYEXOAGlCItJhgzFzsK92LzDhdNrM/R5W+OpSM9t3eU7YFiKdATyaLUuJnQOnmUMmzaSoBGyA= X-Received: by 2002:a25:7647:: with SMTP id r68mr7969484ybc.432.1627062488117; Fri, 23 Jul 2021 10:48:08 -0700 (PDT) MIME-Version: 1.0 References: <20210723113405.427004-1-matthew.auld@intel.com> In-Reply-To: <20210723113405.427004-1-matthew.auld@intel.com> From: Jason Ekstrand Date: Fri, 23 Jul 2021 12:47:57 -0500 Message-ID: Subject: Re: [PATCH] drm/i915/userptr: Probe existence of backing struct pages upon creation To: Matthew Auld Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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_Hellstr=C3=B6m?= , Tvrtko Ursulin , Jordan Justen , Intel GFX , Tvrtko Ursulin , Maling list - DRI developers , Chris Wilson , Kenneth Graunke , Daniel Vetter Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12044 On Fri, Jul 23, 2021 at 6:35 AM Matthew Auld wrote= : > > 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 Hellstr=C3=B6m > 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/dr= m/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 =3D { > > #endif > > +static int > +probe_range(struct mm_struct *mm, unsigned long addr, unsigned long len) > +{ > + const unsigned long end =3D addr + len; > + struct vm_area_struct *vma; > + int ret =3D -EFAULT; > + > + mmap_read_lock(mm); > + for (vma =3D find_vma(mm, addr); vma; vma =3D vma->vm_next) { > + /* Check for holes, note that we also update the addr bel= ow */ > + if (vma->vm_start > addr) > + break; > + > + if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) > + break; > + > + if (vma->vm_end >=3D end) { > + ret =3D 0; > + break; > + } > + > + addr =3D vma->vm_end; > + } > + mmap_read_unlock(mm); > + > + return ret; > +} > + > /* > * Creates a new mm object that wraps some normal memory from the proces= s > * 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 =3D probe_range(current->mm, args->user_ptr, args->us= er_size); > + if (ret) > + return ret; > + } > + > #ifdef CONFIG_MMU_NOTIFIER > obj =3D i915_gem_object_alloc(); > if (obj =3D=3D 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 e= rror 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 va= lid. > + * For example if some garbage address is given to the kernel, th= en this > + * should complain. > + * > + * Returns -EFAULT if the probe failed. > + * > + * Note that this doesn't populate the backing pages, and also do= esn't > + * guarantee that the object will remain valid when the object is > + * eventually used. > + * > + * The kernel supports this feature if I915_PARAM_HAS_USERPTR_PRO= BE > + * 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 >