From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55503) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ehDur-0003WJ-Lr for qemu-devel@nongnu.org; Thu, 01 Feb 2018 07:24:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ehDun-0000HN-MR for qemu-devel@nongnu.org; Thu, 01 Feb 2018 07:24:33 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33554) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ehDun-0000Gf-Cd for qemu-devel@nongnu.org; Thu, 01 Feb 2018 07:24:29 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 154F72815B for ; Thu, 1 Feb 2018 12:24:28 +0000 (UTC) References: <20180201112028.23552-1-peterx@redhat.com> From: Marcel Apfelbaum Message-ID: <90b4bc63-94cd-ec0f-32c8-c16df8ee84cf@redhat.com> Date: Thu, 1 Feb 2018 14:24:15 +0200 MIME-Version: 1.0 In-Reply-To: <20180201112028.23552-1-peterx@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] pcie-root-port: let it has higher migrate priority List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Xu , qemu-devel@nongnu.org, "Dr . David Alan Gilbert" Cc: Alex Williamson , "Michael S . Tsirkin" , Juan Quintela , Laurent Vivier Hi Peter, On 01/02/2018 13:20, Peter Xu wrote: > In the past, we prioritized IOMMU migration so that we have such a > priority order: > > IOMMU > PCI Devices > > When migrating a guest with both vIOMMU and pcie-root-port, we'll always > migrate vIOMMU first, since pcie-root-port will be seen to have the same > priority of general PCI devices. > > That's problematic. > > The thing is that PCI bus number information is stored in the root port, > and that is needed by vIOMMU during post_load(), e.g., to figure out > context entry for a device. If we don't have correct bus numbers for > devices, we won't be able to recover device state of the DMAR memory > regions, and things will be messed up. > > So let's boost the PCIe root ports to be even with higher priority: > > PCIe Root Port > IOMMU > PCI Devices > > A smoke test shows that this patch fixes bug 1538953. > > CC: Alex Williamson > CC: Marcel Apfelbaum > CC: Michael S. Tsirkin > CC: Dr. David Alan Gilbert > CC: Juan Quintela > CC: Laurent Vivier > Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1538953 > Reported-by: Maxime Coquelin > Signed-off-by: Peter Xu > --- > Marcel & all, > > I think it's possible that we need similar thing for other bridge-like > devices, but I'm not that familiar. Would you help confirm? Thanks, Is a pity we don't have a way to mark the migration priority in a base class. Dave, maybe we do have a way? In the meantime you would need to add it also to: - ioh3420 (Intel root port) - xio3130_downstream (Intel switch downstream port) - xio3130_upstream (The counterpart of the above, you want the whole switch to be migrated before loading the IOMMU device state) - pcie_pci_bridge (for pci devices) - pci-pci bridge (if for some reason you have one attached to the pcie_pci_brdge) - i82801b11 (dmi-pci bridge, we want to deprecate it bu is there for now) Thanks, Marcel > hw/pci-bridge/gen_pcie_root_port.c | 1 + > include/migration/vmstate.h | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/hw/pci-bridge/gen_pcie_root_port.c b/hw/pci-bridge/gen_pcie_root_port.c > index 0e2f2e8bf1..e6ff1effd8 100644 > --- a/hw/pci-bridge/gen_pcie_root_port.c > +++ b/hw/pci-bridge/gen_pcie_root_port.c > @@ -101,6 +101,7 @@ static void gen_rp_realize(DeviceState *dev, Error **errp) > > static const VMStateDescription vmstate_rp_dev = { > .name = "pcie-root-port", > + .priority = MIG_PRI_PCIE_ROOT_PORT, > .version_id = 1, > .minimum_version_id = 1, > .post_load = pcie_cap_slot_post_load, > diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h > index 8c3889433c..491449db9f 100644 > --- a/include/migration/vmstate.h > +++ b/include/migration/vmstate.h > @@ -148,6 +148,7 @@ enum VMStateFlags { > typedef enum { > MIG_PRI_DEFAULT = 0, > MIG_PRI_IOMMU, /* Must happen before PCI devices */ > + MIG_PRI_PCIE_ROOT_PORT, /* Must happen before IOMMU */ > MIG_PRI_GICV3_ITS, /* Must happen before PCI devices */ > MIG_PRI_GICV3, /* Must happen before the ITS */ > MIG_PRI_MAX, >