[Qemu-devel] [PATCH 11/13] iommu: Allow PCI to use IOMMU infrastructure

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

From: David Gibson <david@gibson.dropbear.id.au>

This patch adds some hooks to let PCI devices and busses use the new IOMMU
infrastructure.  When IOMMU support is enabled, each PCI device now
contains a DMAContext * which is used by the pci_dma_*() wrapper functions.

By default, the contexts are initialized to NULL, assuming no IOMMU.
However the platform or host bridge code which sets up the PCI bus can use
pci_setup_iommu() to set a function which will determine the correct
DMAContext for a given PCI device.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
 hw/pci.c           |    9 +++++++++
 hw/pci.h           |    9 +++++++--
 hw/pci_internals.h |    2 ++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index bdfb3d6..c8d16a4 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -775,6 +775,9 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
         return NULL;
     }
     pci_dev->bus = bus;
+    if (bus->dma_context_fn) {
+        pci_dev->dma = bus->dma_context_fn(bus, bus->dma_context_opaque, devfn);
+    }
     pci_dev->devfn = devfn;
     pstrcpy(pci_dev->name, sizeof(pci_dev->name), name);
     pci_dev->irq_state = 0;
@@ -2021,6 +2024,12 @@ static void pci_device_class_init(ObjectClass *klass, void *data)
     k->props = pci_props;
 }
 
+void pci_setup_iommu(PCIBus *bus, PCIDMAContextFunc fn, void *opaque)
+{
+    bus->dma_context_fn = fn;
+    bus->dma_context_opaque = opaque;
+}
+
 static TypeInfo pci_device_type_info = {
     .name = TYPE_PCI_DEVICE,
     .parent = TYPE_DEVICE,
diff --git a/hw/pci.h b/hw/pci.h
index 99b7e61..c099766 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -179,6 +179,7 @@ typedef void (*MSIVectorReleaseNotifier)(PCIDevice *dev, unsigned int vector);
 
 struct PCIDevice {
     DeviceState qdev;
+
     /* PCI config space */
     uint8_t *config;
 
@@ -200,6 +201,7 @@ struct PCIDevice {
     int32_t devfn;
     char name[64];
     PCIIORegion io_regions[PCI_NUM_REGIONS];
+    DMAContext *dma;
 
     /* do not access the following fields */
     PCIConfigReadFunc *config_read;
@@ -324,6 +326,10 @@ int pci_read_devaddr(Monitor *mon, const char *addr, int *domp, int *busp,
 
 void pci_device_deassert_intx(PCIDevice *dev);
 
+typedef DMAContext *(*PCIDMAContextFunc)(PCIBus *, void *, int);
+
+void pci_setup_iommu(PCIBus *bus, PCIDMAContextFunc fn, void *opaque);
+
 static inline void
 pci_set_byte(uint8_t *config, uint8_t val)
 {
@@ -560,8 +566,7 @@ static inline uint32_t pci_config_size(const PCIDevice *d)
 /* DMA access functions */
 static inline DMAContext *pci_dma_context(PCIDevice *dev)
 {
-    /* Stub for when we have no PCI iommu support */
-    return NULL;
+    return dev->dma;
 }
 
 static inline int pci_dma_rw(PCIDevice *dev, dma_addr_t addr,
diff --git a/hw/pci_internals.h b/hw/pci_internals.h
index 399c6d4..e8bc9f6 100644
--- a/hw/pci_internals.h
+++ b/hw/pci_internals.h
@@ -17,6 +17,8 @@
 
 struct PCIBus {
     BusState qbus;
+    PCIDMAContextFunc dma_context_fn;
+    void *dma_context_opaque;
     uint8_t devfn_min;
     pci_set_irq_fn set_irq;
     pci_map_irq_fn map_irq;
-- 
1.7.9.5