From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH 1/1] iommu/vt-d: Leave scalable mode default off Date: Wed, 30 Jan 2019 17:24:33 +0100 Message-ID: <20190130162433.ac3gzibnurwgubzf@8bytes.org> References: <20190124023132.20410-1-baolu.lu@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190124023132.20410-1-baolu.lu@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Lu Baolu Cc: David Woodhouse , ashok.raj@intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Liu Yi L , Jacob Pan List-Id: iommu@lists.linux-foundation.org On Thu, Jan 24, 2019 at 10:31:32AM +0800, Lu Baolu wrote: > Commit 765b6a98c1de3 ("iommu/vt-d: Enumerate the scalable > mode capability") enables VT-d scalable mode if hardware > advertises the capability. As we will bring up different > features and use cases to upstream in different patch > series, it will leave some intermediate kernel versions > which support partial features. Hence, end user might run > into problems when they use such kernels on bare metals > or virtualization environments. > > This leaves scalable mode default off and end users could > turn it on with "intel-iommu=sm_on" only when they have > clear ideas about which scalable features are supported > in the kernel. > > Cc: Liu Yi L > Cc: Jacob Pan > Suggested-by: Ashok Raj > Suggested-by: Kevin Tian > Signed-off-by: Lu Baolu Applied to iommu/fixes, thanks.