[Qemu-devel] [PATCH 4/4] spapr_pci: Allow VFIO devices to work on the normal PCI host bridge

[David Gibson <david@gibson.dropbear.id.au>]

The core VFIO infrastructure more or less allows VFIO devices to work
on any normal guest PCI host bridge (PHB) without extra logic.
However, the "spapr-pci-host-bridge" device (as opposed to the special
"spapr-pci-vfio-host-bridge" device) breaks this by using a partially
KVM accelerated implementation of the guest kernel IOMMU which won't
work with VFIO devices, without additional kernel support.

This patch allows VFIO devices to work on the spapr-pci-host-bridge,
by having it switch off KVM TCE acceleration when a VFIO device is
added to the PHB (either on startup, or by hotplug).

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 hw/ppc/spapr_pci.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index cb7c351..55fa8db 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -1083,6 +1083,12 @@ static void spapr_phb_add_pci_device(sPAPRDRConnector *drc,
     void *fdt = NULL;
     int fdt_start_offset = 0, fdt_size;
 
+    if (object_dynamic_cast(OBJECT(pdev), "vfio-pci")) {
+        sPAPRTCETable *tcet = spapr_tce_find_by_liobn(phb->dma_liobn);
+
+        spapr_tce_set_need_vfio(tcet, true);
+    }
+
     if (dev->hotplugged) {
         fdt = create_device_tree(&fdt_size);
         fdt_start_offset = spapr_create_pci_child_dt(phb, pdev, fdt, 0);
-- 
2.4.3