From patchwork Tue Oct 13 13:22:26 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 7385341 Return-Path: X-Original-To: patchwork-intel-gfx@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id B1C23BEEA4 for ; Tue, 13 Oct 2015 13:22:52 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B33EB205B3 for ; Tue, 13 Oct 2015 13:22:51 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id 28F4B205F7 for ; Tue, 13 Oct 2015 13:22:46 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9CE5C6E363; Tue, 13 Oct 2015 06:22:45 -0700 (PDT) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [87.106.93.118]) by gabe.freedesktop.org (Postfix) with ESMTP id 2A7676E363 for ; Tue, 13 Oct 2015 06:22:44 -0700 (PDT) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from haswell.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 46557701-1500048 for multiple; Tue, 13 Oct 2015 14:22:40 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Tue, 13 Oct 2015 14:22:28 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Tue, 13 Oct 2015 14:22:26 +0100 Message-Id: <1444742546-27401-1-git-send-email-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.6.1 MIME-Version: 1.0 X-Originating-IP: 78.156.65.138 X-Country: code=GB country="United Kingdom" ip=78.156.65.138 Cc: Daniel Vetter , stable@vger.kernel.org Subject: [Intel-gfx] [PATCH] drm/i915: Deny wrapping an userptr into a framebuffer X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Pinning a userptr onto the hardware raises interesting questions about the lifetime of such a surface as the framebuffer extends that life beyond the client's address space. That is the hardware will need to keep scanning out from the backing storage even after the client wants to remap its address space. As the hardware pins the backing storage, the userptr becomes invalid and this raises a WARN when the clients tries to unmap its address space. The situation can be even more complicated when the buffer is passed between processes, between a client and display server, where the lifetime and hardware access is even more confusing. Deny it. Signed-off-by: Chris Wilson Cc: Daniel Vetter Cc: Tvrtko Ursulin Cc: Micha? Winiarski Cc: stable@vger.kernel.org Reviewed-by: Tvrtko Ursulin Reviewed-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_gem_userptr.c | 5 ++++- drivers/gpu/drm/i915/intel_display.c | 5 +++++ 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c index 2dd911ab3019..3ce1b557f7c4 100644 --- a/drivers/gpu/drm/i915/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c @@ -974,7 +974,10 @@ out: * Also note, that the object created here is not currently a "first class" * object, in that several ioctls are banned. These are the CPU access * ioctls: mmap(), pwrite and pread. In practice, you are expected to use - * direct access via your pointer rather than use those ioctls. + * direct access via your pointer rather than use those ioctls. Another + * restriction is that we do not allow userptr surfaces to be pinned to the + * hardware and so we reject any attempt to create a framebuffer out of a + * userptr. * * If you think this is a good interface to use to pass GPU memory between * drivers, please use dma-buf instead. In fact, wherever possible use diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index b89131654a0e..d1deaedcc4ce 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -14116,6 +14116,11 @@ static int intel_user_framebuffer_create_handle(struct drm_framebuffer *fb, struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb); struct drm_i915_gem_object *obj = intel_fb->obj; + if (obj->userptr.mm) { + DRM_DEBUG("attempting to use a userptr for a framebuffer, denied\n"); + return -EINVAL; + } + return drm_gem_handle_create(file, &obj->base, handle); }