On Mon, Sep 18, 2023 at 02:23:48PM +0200, Cédric Le Goater wrote: > On 9/18/23 13:51, Jason Gunthorpe wrote: > > On Fri, Sep 15, 2023 at 02:42:48PM +0200, Cédric Le Goater wrote: > > > On 8/30/23 12:37, Zhenzhong Duan wrote: > > > > Hi All, > > > > > > > > As the kernel side iommufd cdev and hot reset feature have been queued, > > > > also hwpt alloc has been added in Jason's for_next branch [1], I'd like > > > > to update a new version matching kernel side update and with rfc flag > > > > removed. Qemu code can be found at [2], look forward more comments! > > > > > > FYI, I have started cleaning up the VFIO support in QEMU PPC. First > > > is the removal of nvlink2, which was dropped from the kernel 2.5 years > > > ago. Next is probably removal of all the PPC bits in VFIO. Code is > > > bitrotting and AFAICT VFIO has been broken on these platforms since > > > 5.18 or so. > > > > It was fixed since then - at least one company (not IBM) still cares > > about vfio on ppc, though I think it is for a DPDK use case not VFIO. > > Indeed. > I just checked on a POWER9 box running a debian sid (6.4) and device > assignment of a simple NIC (e1000e) in a ubuntu 23.04 guest worked > correctly. Using a 6.6-rc1 on the host worked also. One improvement > would be to reflect in the Kconfig files that CONFIG_IOMMUFD is not > supported on PPC so that it can not be selected.
When we did this I thought there were other iommu drivers on Power that did work with VFIO (fsl_pamu specifically), but it turns out that ppc iommu driver doesn't support VFIO and the VFIO FSL stuff is for ARM only. So it could be done... These days I believe we have the capacity to do the PPC stuff without making it so special - it would be alot of work but the road is pretty clear. At least if qemu wants to remove PPC VFIO support I would not object. Jason
