Am Wed, 26 Sep 2012 16:04:03 -0600 schrieb Alex Williamson <alex.william...@redhat.com>:
> On Wed, 2012-09-26 at 13:50 -0600, Alex Williamson wrote: > > On Wed, 2012-09-26 at 10:21 -0600, Alex Williamson wrote: > > > On Wed, 2012-09-26 at 17:10 +0200, Roedel, Joerg wrote: > > > > On Wed, Sep 26, 2012 at 08:35:59AM -0600, Alex Williamson wrote: > > > > > Hmm, that throws a kink in iommu groups. So perhaps we need to make > > > > > an > > > > > alias interface to iommu groups. Seems like this could just be an > > > > > extra > > > > > parameter to iommu_group_get and iommu_group_add_device (empty in the > > > > > typical case). Then we have the problem of what's the type for an > > > > > alias? For AMI-Vi, it's a u16, but we need to be more generic than > > > > > that. Maybe iommu groups should just treat it as a void* so iommus > > > > > can > > > > > use a pointer to some structure or a fixed value like a u16 bus:slot. > > > > > Thoughts? > > > > > > > > Good question. The iommu-groups are part of the IOMMU-API, with an > > > > interface to the IOMMU drivers and one to the users of IOMMU-API. So the > > > > alias handling itself should be a function of the interface to the IOMMU > > > > driver. In general the interface should not be bus specific. > > > > > > > > So a void pointer seems the only logical choice then. But I would not > > > > limit its scope to alias handling. How about making it a bus-private > > > > pointer where IOMMU driver store bus-specific information. That way we > > > > make sure that there is one struct per bus-type for this pointer, and > > > > not one structure per IOMMU driver. > > > > > > I thought of another approach that may actually be more 3.6 worthy. > > > What if we just make the iommu driver handle it? For instance, > > > amd_iommu can walk the alias table looking for entries that use the same > > > alias and get the device via pci_get_bus_and_slot. If it finds a device > > > with an iommu group, it attaches the new device to the same group, > > > hiding anything about aliases from the group layer. It just groups all > > > devices within the range. I think the only complication is making sure > > > we're safe around device hotplug while we're doing this. Thanks, > > > > I think this could work. Instead of searching for other devices, check > > for or allocate an iommu group on the alias dev_data, any "virtual" > > aliases use that iommu group. Florian, could you test this as well? > > Here's a lockdep clean version of it: > > amd_iommu: Handle aliases not backed by devices > [ skipped patch ] yes, this patch is working for me, too. I also tested your second patch, it was working as well. thanks, Florian _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
