From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH] iommu/vt-d: Flush old iotlb for kdump when the device gets context mapped Date: Wed, 30 Nov 2016 15:26:43 +0100 Message-ID: <20161130142642.GJ2078@8bytes.org> References: <1479286950-21885-1-git-send-email-xlpang@redhat.com> <582C232F.6080205@redhat.com> <582D1A40.409@redhat.com> <20161129143547.GG2078@8bytes.org> <583E8A9B.7070906@redhat.com> <20161130090327.GA4192@x1> <20161130095334.GB4192@x1> <20161130102334.GC4192@x1> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20161130102334.GC4192@x1> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Baoquan He Cc: Don Brace , kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Dave Young , LKML , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Myron Stowe , David Woodhouse List-Id: iommu@lists.linux-foundation.org On Wed, Nov 30, 2016 at 06:23:34PM +0800, Baoquan He wrote: > OK, talked with Xunlei. The old cache could be entry with present bit > set. -EPARSE Anyway, what I was trying to say is, that the IOMMU TLB is tagged with domain-ids, and that there is also a context-cache which maps device-ids to domain-ids. If we update the context entry then we need to flush only the context entry, as it will point to a new domain-id then and future IOTLB lookups in the IOMMU will be using the new domain-id and do not match the old entries. Joerg