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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 830F6C433F5 for ; Wed, 10 Nov 2021 12:09:09 +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 4190660FED for ; Wed, 10 Nov 2021 12:09:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4190660FED Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.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 EF3596E12A; Wed, 10 Nov 2021 12:09:06 +0000 (UTC) Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by gabe.freedesktop.org (Postfix) with ESMTPS id 091846E11F; Wed, 10 Nov 2021 12:09:04 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10163"; a="232601913" X-IronPort-AV: E=Sophos;i="5.87,223,1631602800"; d="scan'208";a="232601913" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Nov 2021 04:08:56 -0800 X-IronPort-AV: E=Sophos;i="5.87,223,1631602800"; d="scan'208";a="582692961" Received: from dkeohane-mobl1.ger.corp.intel.com (HELO [10.213.222.153]) ([10.213.222.153]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Nov 2021 04:08:54 -0800 To: Lu Baolu , Intel-gfx@lists.freedesktop.org References: <20211109121759.170915-1-tvrtko.ursulin@linux.intel.com> <6e8c55a7-45b6-57ab-35f7-d522401efccb@linux.intel.com> <4d1a0ab9-e0d8-2ed9-1fc4-9ffaf2f19bef@linux.intel.com> <7b2e1427-69cf-8f5d-0c15-73c4e602953d@linux.intel.com> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc Message-ID: <2a1ae709-19f8-7983-b171-98ec2f3f010a@linux.intel.com> Date: Wed, 10 Nov 2021 12:08:53 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <7b2e1427-69cf-8f5d-0c15-73c4e602953d@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [Intel-gfx] [PATCH] drm/i915: Use per device iommu check 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: dri-devel@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On 10/11/2021 12:04, Lu Baolu wrote: > On 2021/11/10 17:30, Tvrtko Ursulin wrote: >> >> On 10/11/2021 07:12, Lu Baolu wrote: >>> Hi Tvrtko, >>> >>> On 2021/11/9 20:17, Tvrtko Ursulin wrote: >>>> From: Tvrtko Ursulin >>>> >>>> On igfx + dgfx setups, it appears that intel_iommu=igfx_off option only >>>> disables the igfx iommu. Stop relying on global intel_iommu_gfx_mapped >>>> and probe presence of iommu domain per device to accurately reflect its >>>> status. >>>> >>>> Signed-off-by: Tvrtko Ursulin >>>> Cc: Lu Baolu >>>> --- >>>> Baolu, is my understanding here correct? Maybe I am confused by both >>>> intel_iommu_gfx_mapped and dmar_map_gfx being globals in the >>>> intel_iommu >>>> driver. But it certainly appears the setup can assign some iommu ops >>>> (and >>>> assign the discrete i915 to iommu group) when those two are set to off. >>> >>> diff --git a/drivers/gpu/drm/i915/i915_drv.h >>> b/drivers/gpu/drm/i915/i915_drv.h >>> index e967cd08f23e..9fb38a54f1fe 100644 >>> --- a/drivers/gpu/drm/i915/i915_drv.h >>> +++ b/drivers/gpu/drm/i915/i915_drv.h >>> @@ -1763,26 +1763,27 @@ static inline bool run_as_guest(void) >>>   #define HAS_D12_PLANE_MINIMIZATION(dev_priv) >>> (IS_ROCKETLAKE(dev_priv) || \ >>>                             IS_ALDERLAKE_S(dev_priv)) >>> >>> -static inline bool intel_vtd_active(void) >>> +static inline bool intel_vtd_active(struct drm_i915_private *i915) >>>   { >>> -#ifdef CONFIG_INTEL_IOMMU >>> -    if (intel_iommu_gfx_mapped) >>> +    if (iommu_get_domain_for_dev(i915->drm.dev)) >>>           return true; >>> -#endif >>> >>>       /* Running as a guest, we assume the host is enforcing VT'd */ >>>       return run_as_guest(); >>>   } >>> >>> Have you verified this change? I am afraid that >>> iommu_get_domain_for_dev() always gets a valid iommu domain even >>> intel_iommu_gfx_mapped == 0. >> >> Yes it seems to work as is: >> >> default: >> >> # grep -i iommu /sys/kernel/debug/dri/*/i915_capabilities >> /sys/kernel/debug/dri/0/i915_capabilities:iommu: enabled >> /sys/kernel/debug/dri/1/i915_capabilities:iommu: enabled >> >> intel_iommu=igfx_off: >> >> # grep -i iommu /sys/kernel/debug/dri/*/i915_capabilities >> /sys/kernel/debug/dri/0/i915_capabilities:iommu: disabled >> /sys/kernel/debug/dri/1/i915_capabilities:iommu: enabled >> >> On my system dri device 0 is integrated graphics and 1 is discrete. > > The drm device 0 has a dedicated iommu. When the user request igfx not > mapped, the VT-d implementation will turn it off to save power. But for > shared iommu, you definitely will get it enabled. Sorry I am not following, what exactly do you mean? Is there a platform with integrated graphics without a dedicated iommu, in which case intel_iommu=igfx_off results in intel_iommu_gfx_mapped == 0 and iommu_get_domain_for_dev returning non-NULL? Regards, Tvrtko