From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com ([192.55.52.115]:25423 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752862AbdDEHoa (ORCPT ); Wed, 5 Apr 2017 03:44:30 -0400 From: Jani Nikula To: Daniel Vetter , Xiong Zhang Cc: intel-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, stable@vger.kernel.org Subject: Re: [Intel-gfx] [PATCH V4] drm/i915: Enhanced disable access to stolen memory as a guest In-Reply-To: <20170405065032.co65xgsqvkgtnokb@phenom.ffwll.local> References: <1491358106-26329-1-git-send-email-xiong.y.zhang@intel.com> <20170405065032.co65xgsqvkgtnokb@phenom.ffwll.local> Date: Wed, 05 Apr 2017 10:44:25 +0300 Message-ID: <87h9231ep2.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: stable-owner@vger.kernel.org List-ID: On Wed, 05 Apr 2017, Daniel Vetter wrote: > On Wed, Apr 05, 2017 at 10:08:26AM +0800, Xiong Zhang wrote: >> Stolen memory is in RMRR and has identity mapping in iommu, so >> gt could access stolen memory in host OS. While RMRR isn't supported >> by kvm, both EPT and guest iommu domain lack of maaping for stolen memory, >> so both vcpu and gt couldn't access stolen memory in guest. >> >> commit "04a68a3 drm/i915/gvt: Disable access to stolen memory as a guest" >> isn't enough in IGD passthrough environment where vgt code doesn't run. This >> patch detects i915 running as a guest through the existence of emulated ISA >> bridge. >> >> v2:GVT-g may run in non qemu (Zhenyu) >> v3:Make commit message clear (Daniel) >> v4:Fix typo >> >> References: c875d2c iommu/vt-d: Exclude devices using RMRRs from IOMMU API domains What does it mean to References: a commit? The message text doesn't say anything about this commit. Does this patch fix commit 04a68a3 or c875d2c? If so, there should be a Fixes: tag. The canonical format for commit references is 04a68a35ce6d ("drm/i915/gvt: Disable access to stolen memory as a guest") c875d2c1b808 ("iommu/vt-d: Exclude devices using RMRRs from IOMMU API domains") In particular, note that 12 digits is preferred for sha1 references to avoid ambiguity in the kernel git repo. >> Link: https://access.redhat.com/sites/default/files/attachments/rmrr-wp1.pdf Please use References: for stuff like this. Link: is reserved for the backlink to the patch and discussion. >> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99028 >> >> Signed-off-by: Xiong Zhang >> Reviewed-by: Zhenyu Wang >> Cc: stable@vger.kernel.org With a Fixes: tag it would be possible to decide which stable kernels to backport to. > Yeah, commit message is now much improved. I'm sorry, but from the fixes backports POV it still lacks clarity. I wouldn't know if and where this should be backported. BR, Jani. > > Reviewed-by: Daniel Vetter > >> --- >> drivers/gpu/drm/i915/i915_drv.c | 1 + >> drivers/gpu/drm/i915/i915_drv.h | 1 + >> drivers/gpu/drm/i915/i915_gem_stolen.c | 4 ++-- >> 3 files changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c >> index 03d9e45..8b807a9 100644 >> --- a/drivers/gpu/drm/i915/i915_drv.c >> +++ b/drivers/gpu/drm/i915/i915_drv.c >> @@ -223,6 +223,7 @@ static void intel_detect_pch(struct drm_i915_private *dev_priv) >> PCI_SUBVENDOR_ID_REDHAT_QUMRANET && >> pch->subsystem_device == >> PCI_SUBDEVICE_ID_QEMU)) { >> + dev_priv->run_on_qemu = true; >> dev_priv->pch_type = >> intel_virt_detect_pch(dev_priv); >> } else >> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h >> index a5947a4..ad95c87 100644 >> --- a/drivers/gpu/drm/i915/i915_drv.h >> +++ b/drivers/gpu/drm/i915/i915_drv.h >> @@ -2145,6 +2145,7 @@ struct drm_i915_private { >> struct intel_uncore uncore; >> >> struct i915_virtual_gpu vgpu; >> + bool run_on_qemu; >> >> struct intel_gvt *gvt; >> >> diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c >> index f3abdc2..6a011b0 100644 >> --- a/drivers/gpu/drm/i915/i915_gem_stolen.c >> +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c >> @@ -409,8 +409,8 @@ int i915_gem_init_stolen(struct drm_i915_private *dev_priv) >> >> mutex_init(&dev_priv->mm.stolen_lock); >> >> - if (intel_vgpu_active(dev_priv)) { >> - DRM_INFO("iGVT-g active, disabling use of stolen memory\n"); >> + if (dev_priv->run_on_qemu || intel_vgpu_active(dev_priv)) { >> + DRM_INFO("Running in guest, disabling use of stolen memory\n"); >> return 0; >> } >> >> -- >> 1.9.1 >> -- Jani Nikula, Intel Open Source Technology Center