* Marcel Apfelbaum (mar...@redhat.com) wrote: > 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 <alex.william...@redhat.com> > > CC: Marcel Apfelbaum <mar...@redhat.com> > > CC: Michael S. Tsirkin <m...@redhat.com> > > CC: Dr. David Alan Gilbert <dgilb...@redhat.com> > > CC: Juan Quintela <quint...@redhat.com> > > CC: Laurent Vivier <lviv...@redhat.com> > > Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1538953 > > Reported-by: Maxime Coquelin <maxime.coque...@redhat.com> > > Signed-off-by: Peter Xu <pet...@redhat.com> > > --- > > 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?
Not that I'm aware of; the 'priority' field is associated with the VMSD and it's not really connected to the class hierarchy at all. Dave > 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, > > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK