> First, multiple QEMU instances cannot access nvme:// devices sharing the > same IOMMU group. I don't think this will ever be possible because it > opens a backdoor around process memory isolation. > > However, a single QEMU (or qemu-storage-daemon) instance should be able > to access multiple nvme:// devices in the same IOMMU group. > Unfortunately the code currently doesn't support that. > util/vfio-helpers.c:qemu_vfio_init_pci() has no logic for sharing > groups/containers. Opening the group fails with EBUSY because the kernel > only allows the file to be opened once at any given time. > > It's possible to extend the util/vfio-helpers.c code to reuse VFIO > groups (and share VFIO containers), but I'm not aware of anyone who is > currently working on that. > > Stefan
Thanks a lot for detailed explanation, it is really helpful. -ck
