On Thu, Mar 02, 2017 at 01:20:53PM +0800, Peter Xu wrote: > On Thu, Mar 02, 2017 at 07:13:08AM +0200, Michael S. Tsirkin wrote: > > On Thu, Mar 02, 2017 at 11:32:18AM +0800, Peter Xu wrote: > > > Intel vIOMMU devices are created with "-device" parameter, while here > > > actually we need to make sure the dmar device be created before other > > > PCI devices (like vfio-pci, virtio-pci ones) so that we know iommu_fn > > > will be setup correctly before realizations of those PCI devices (it is > > > legal that PCI device fetch these info during its realization). Now this > > > ordering yet cannot be achieved elsewhere, and devices will be created > > > in the order that user specified. We need to avoid that. > > > > > > This patch tries to detect this kind of misordering issue during init of > > > VT-d device, then report to guest if misordering happened. In the > > > future, we can provide something better to solve it, e.g., to support > > > device init ordering, then we can live without this patch. > > > > > > Signed-off-by: Peter Xu <pet...@redhat.com> > > > > Unfortunately with virtio it's a regression, as it used to > > work with iommu. So I'm afraid we need to look into supporting > > arbitrary order right now :( > > No problem. > > But do you think that would be a possible material for 2.9? > > Thanks, > > -- peterx
Looks like it's that or revert the virtio caching feature? -- MST
