spapr_pci_vfio: Add spapr-pci-vfio-host-bridge to support vfio

The patch adds a spapr-pci-vfio-host-bridge device type
which is a PCI Host Bridge with VFIO support. The new device
inherits from the spapr-pci-host-bridge device and adds an "iommu"
property which is an IOMMU id. This ID represents a minimal entity
for which IOMMU isolation can be guaranteed. In SPAPR architecture IOMMU
group is called a Partitionable Endpoint (PE).

Current implementation supports one IOMMU id per QEMU VFIO PHB. Since
SPAPR allows multiple PHB for no extra cost, this does not seem to
be a problem. This limitation may change in the future though.

Example of use:
Configure and Add 3 functions of a multifunctional device to QEMU:
(the NEC PCI USB card is used as an example here):
-device spapr-pci-vfio-host-bridge,id=USB,iommu=4,index=7 \
-device vfio-pci,host=4:0:1.0,addr=1.0,bus=USB,multifunction=true
-device vfio-pci,host=4:0:1.1,addr=1.1,bus=USB
-device vfio-pci,host=4:0:1.2,addr=1.2,bus=USB

where:
* index=7 is a QEMU PHB index (used as source for MMIO/MSI/IO windows
offset);
* iommu=4 is an IOMMU id which can be found in sysfs:
[aik@vpl2 ~]$ cd /sys/bus/pci/devices/0004:00:00.0/
[aik@vpl2 0004:00:00.0]$ ls -l iommu_group
lrwxrwxrwx 1 root root 0 Jun  5 12:49 iommu_group -> ../../../kernel/iommu_groups/4

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 3 insertions, 0 deletions

diff --git a/hw/ppc/Makefile.objs b/hw/ppc/Makefile.objs
index ea747f0a20..edd44d03e7 100644
--- a/hw/ppc/Makefile.objs
+++ b/hw/ppc/Makefile.objs
@@ -4,6 +4,9 @@ obj-y += ppc.o ppc_booke.o
 obj-$(CONFIG_PSERIES) += spapr.o spapr_vio.o spapr_events.o
 obj-$(CONFIG_PSERIES) += spapr_hcall.o spapr_iommu.o spapr_rtas.o
 obj-$(CONFIG_PSERIES) += spapr_pci.o
+ifeq ($(CONFIG_PCI)$(CONFIG_PSERIES)$(CONFIG_LINUX), yyy)
+obj-y += spapr_pci_vfio.o
+endif
 # PowerPC 4xx boards
 obj-y += ppc405_boards.o ppc4xx_devs.o ppc405_uc.o ppc440_bamboo.o
 obj-y += ppc4xx_pci.o