From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Date: Thu, 23 Mar 2017 17:52:18 +0100 From: Joerg Roedel To: Jean-Philippe Brucker Subject: Re: [RFC PATCH 24/30] iommu: Specify PASID state when unbinding a task Message-ID: <20170323165218.GL7266@8bytes.org> References: <20170227195441.5170-1-jean-philippe.brucker@arm.com> <20170227195441.5170-25-jean-philippe.brucker@arm.com> <20170322154429.GE7266@8bytes.org> <20170322225320.GF7266@8bytes.org> <20170323143014.GK7266@8bytes.org> <20170323145311.GA22972@e106794-lin.localdomain> MIME-Version: 1.0 In-Reply-To: <20170323145311.GA22972@e106794-lin.localdomain> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Lorenzo Pieralisi , Shanker Donthineni , kvm@vger.kernel.org, Catalin Marinas , Sinan Kaya , Will Deacon , iommu@lists.linux-foundation.org, Harv Abdulhamid , Alex Williamson , linux-pci@vger.kernel.org, Bjorn Helgaas , Robin Murphy , David Woodhouse , linux-arm-kernel@lists.infradead.org, Nate Watterson Content-Type: text/plain; charset="us-ascii" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+bjorn=helgaas.com@lists.infradead.org List-ID: On Thu, Mar 23, 2017 at 03:52:14PM +0000, Jean-Philippe Brucker wrote: > On 23/03/17 14:30, Joerg Roedel wrote: > > Are you sure about the meaning of the stop-marker? Can you point me to > > where it is specified? > > The concept is introduced in the PCI ECN that adds PASIDs to the ATS > specification. I have the following link, which is probably behind a > wall: > > https://pcisig.com/sites/default/files/specification_documents/ECN-PASID-ATS-2011-03-31.pdf > > A Stop Marker is a PPR with flags Read=Write=0, Last=1, targeting the > PASID that is being decommissioned. In section 4.1.2, the specifications > details the two device-specific ways of stopping use of a PASID, with or > without a Stop Marker. When done with a Stop Marker, the function doesn't > have to wait for any outstanding PPR to return, the Stop Marker serves as > a PASID barrier. Thanks for that, I have a closer look. Is that stopper packet visible to software (e.g. is an entry created in the queue)? I have to check whether the AMD IOMMU makes this visible. Joerg _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel