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 86935C433EF for ; Wed, 10 Nov 2021 09:31:13 +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 3FB9A61207 for ; Wed, 10 Nov 2021 09:31:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3FB9A61207 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 BC60E6E44D; Wed, 10 Nov 2021 09:31:07 +0000 (UTC) Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTPS id 94BBE6E123; Wed, 10 Nov 2021 09:31:05 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10163"; a="232482169" X-IronPort-AV: E=Sophos;i="5.87,223,1631602800"; d="scan'208";a="232482169" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Nov 2021 01:31:04 -0800 X-IronPort-AV: E=Sophos;i="5.87,223,1631602800"; d="scan'208";a="582588283" 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 01:30:50 -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> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc Message-ID: <4d1a0ab9-e0d8-2ed9-1fc4-9ffaf2f19bef@linux.intel.com> Date: Wed, 10 Nov 2021 09:30:48 +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: <6e8c55a7-45b6-57ab-35f7-d522401efccb@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 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. Regards, Tvrtko > > A possible way could look like this: > > static bool intel_vtd_active(struct drm_i915_private *i915) > { >         struct iommu_domain *domain; > >         domain = iommu_get_domain_for_dev(i915->drm.dev); > >         if (domain && (domain->type & __IOMMU_DOMAIN_PAGING)) >                 return true; > >     ... ... > } > > Actually I don't like this either since it checks the domain->type out > of the iommu subsystem. We could refactor this later by export an iommu > interface for this check. > > Best regards, > baolu