hw/pci: modify pci_setup_iommu() to set PCIIOMMUOps

This patch modifies pci_setup_iommu() to set PCIIOMMUOps
instead of setting PCIIOMMUFunc. PCIIOMMUFunc is used to
get an address space for a PCI device in vendor specific
way. The PCIIOMMUOps still offers this functionality. But
using PCIIOMMUOps leaves space to add more iommu related
vendor specific operations.

Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Yi Sun <yi.y.sun@linux.intel.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hervé Poussineau <hpoussin@reactos.org>
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Cc: BALATON Zoltan <balaton@eik.bme.hu>
Cc: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Cc: Jagannathan Raman <jag.raman@oracle.com>
Cc: Matthew Rosato <mjrosato@linux.ibm.com>
Cc: Eric Farman <farman@linux.ibm.com>
Cc: Halil Pasic <pasic@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Thomas Huth <thuth@redhat.com>
Cc: Helge Deller <deller@gmx.de>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
[ clg: - refreshed on latest QEMU
       - included hw/remote/iommu.c
       - documentation update
       - asserts in pci_setup_iommu()
       - removed checks on iommu_bus->iommu_ops->get_address_space
       - included Elroy PCI host (PA-RISC) ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>

docs/devel/index-api.rst

@@ -11,6 +11,7 @@ generated from in-code annotations to function prototypes.
    loads-stores
    memory
    modules
+   pci
    qom-api
    qdev-api
    ui

docs/devel/pci.rst

@@ -0,0 +1,8 @@
+=============
+PCI subsystem
+=============
+
+API Reference
+-------------
+
+.. kernel-doc:: include/hw/pci/pci.h

hw/alpha/typhoon.c

@@ -738,6 +738,10 @@ static AddressSpace *typhoon_pci_dma_iommu(PCIBus *bus, void *opaque, int devfn)
     return &s->pchip.iommu_as;
 }
 
+static const PCIIOMMUOps typhoon_iommu_ops = {
+    .get_address_space = typhoon_pci_dma_iommu,
+};
+
 static void typhoon_set_irq(void *opaque, int irq, int level)
 {
     TyphoonState *s = opaque;
@@ -897,7 +901,7 @@ PCIBus *typhoon_init(MemoryRegion *ram, qemu_irq *p_isa_irq,
                              "iommu-typhoon", UINT64_MAX);
     address_space_init(&s->pchip.iommu_as, MEMORY_REGION(&s->pchip.iommu),
                        "pchip0-pci");
-    pci_setup_iommu(b, typhoon_pci_dma_iommu, s);
+    pci_setup_iommu(b, &typhoon_iommu_ops, s);
 
     /* Pchip0 PCI special/interrupt acknowledge, 0x801.F800.0000, 64MB.  */
     memory_region_init_io(&s->pchip.reg_iack, OBJECT(s), &alpha_pci_iack_ops,

hw/arm/smmu-common.c

@@ -605,6 +605,10 @@ static AddressSpace *smmu_find_add_as(PCIBus *bus, void *opaque, int devfn)
     return &sdev->as;
 }
 
+static const PCIIOMMUOps smmu_ops = {
+    .get_address_space = smmu_find_add_as,
+};
+
 IOMMUMemoryRegion *smmu_iommu_mr(SMMUState *s, uint32_t sid)
 {
     uint8_t bus_n, devfn;
@@ -661,7 +665,7 @@ static void smmu_base_realize(DeviceState *dev, Error **errp)
     s->smmu_pcibus_by_busptr = g_hash_table_new(NULL, NULL);
 
     if (s->primary_bus) {
-        pci_setup_iommu(s->primary_bus, smmu_find_add_as, s);
+        pci_setup_iommu(s->primary_bus, &smmu_ops, s);
     } else {
         error_setg(errp, "SMMU is not attached to any PCI bus!");
     }

hw/i386/amd_iommu.c

@@ -1450,6 +1450,10 @@ static AddressSpace *amdvi_host_dma_iommu(PCIBus *bus, void *opaque, int devfn)
     return &iommu_as[devfn]->as;
 }
 
+static const PCIIOMMUOps amdvi_iommu_ops = {
+    .get_address_space = amdvi_host_dma_iommu,
+};
+
 static const MemoryRegionOps mmio_mem_ops = {
     .read = amdvi_mmio_read,
     .write = amdvi_mmio_write,
@@ -1581,7 +1585,7 @@ static void amdvi_sysbus_realize(DeviceState *dev, Error **errp)
                           AMDVI_MMIO_SIZE);
     memory_region_add_subregion(get_system_memory(), AMDVI_BASE_ADDR,
                                 &s->mmio);
-    pci_setup_iommu(bus, amdvi_host_dma_iommu, s);
+    pci_setup_iommu(bus, &amdvi_iommu_ops, s);
     amdvi_init(s);
 }
 

hw/i386/intel_iommu.c

@@ -4088,6 +4088,10 @@ static AddressSpace *vtd_host_dma_iommu(PCIBus *bus, void *opaque, int devfn)
     return &vtd_as->as;
 }
 
+static PCIIOMMUOps vtd_iommu_ops = {
+    .get_address_space = vtd_host_dma_iommu,
+};
+
 static bool vtd_decide_config(IntelIOMMUState *s, Error **errp)
 {
     X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);
@@ -4210,7 +4214,7 @@ static void vtd_realize(DeviceState *dev, Error **errp)
     s->vtd_address_spaces = g_hash_table_new_full(vtd_as_hash, vtd_as_equal,
                                       g_free, g_free);
     vtd_init(s);
-    pci_setup_iommu(bus, vtd_host_dma_iommu, dev);
+    pci_setup_iommu(bus, &vtd_iommu_ops, dev);
     /* Pseudo address space under root PCI bus. */
     x86ms->ioapic_as = vtd_host_dma_iommu(bus, s, Q35_PSEUDO_DEVFN_IOAPIC);
     qemu_add_machine_init_done_notifier(&vtd_machine_done_notify);

hw/pci-host/astro.c

@@ -345,6 +345,10 @@ static AddressSpace *elroy_pcihost_set_iommu(PCIBus *bus, void *opaque,
     return &s->astro->iommu_as;
 }
 
+static const PCIIOMMUOps elroy_pcihost_iommu_ops = {
+    .get_address_space = elroy_pcihost_set_iommu,
+};
+
 /*
  * Encoding in IOSAPIC:
  * base_addr == 0xfffa0000, we want to get 0xa0ff0000.
@@ -834,7 +838,7 @@ static void astro_realize(DeviceState *obj, Error **errp)
                                  &elroy->pci_io);
 
         /* Host memory as seen from the PCI side, via the IOMMU.  */
-        pci_setup_iommu(PCI_HOST_BRIDGE(elroy)->bus, elroy_pcihost_set_iommu,
+        pci_setup_iommu(PCI_HOST_BRIDGE(elroy)->bus, &elroy_pcihost_iommu_ops,
                                  elroy);
     }
 }

hw/pci-host/designware.c

@@ -663,6 +663,10 @@ static AddressSpace *designware_pcie_host_set_iommu(PCIBus *bus, void *opaque,
     return &s->pci.address_space;
 }
 
+static const PCIIOMMUOps designware_iommu_ops = {
+    .get_address_space = designware_pcie_host_set_iommu,
+};
+
 static void designware_pcie_host_realize(DeviceState *dev, Error **errp)
 {
     PCIHostState *pci = PCI_HOST_BRIDGE(dev);
@@ -705,7 +709,7 @@ static void designware_pcie_host_realize(DeviceState *dev, Error **errp)
     address_space_init(&s->pci.address_space,
                        &s->pci.address_space_root,
                        "pcie-bus-address-space");
-    pci_setup_iommu(pci->bus, designware_pcie_host_set_iommu, s);
+    pci_setup_iommu(pci->bus, &designware_iommu_ops, s);
 
     qdev_realize(DEVICE(&s->root), BUS(pci->bus), &error_fatal);
 }

hw/pci-host/dino.c

@@ -354,6 +354,10 @@ static AddressSpace *dino_pcihost_set_iommu(PCIBus *bus, void *opaque,
     return &s->bm_as;
 }
 
+static const PCIIOMMUOps dino_iommu_ops = {
+    .get_address_space = dino_pcihost_set_iommu,
+};
+
 /*
  * Dino interrupts are connected as shown on Page 78, Table 23
  * (Little-endian bit numbers)
@@ -481,7 +485,7 @@ static void dino_pcihost_init(Object *obj)
         g_free(name);
     }
 
-    pci_setup_iommu(phb->bus, dino_pcihost_set_iommu, s);
+    pci_setup_iommu(phb->bus, &dino_iommu_ops, s);
 
     sysbus_init_mmio(sbd, &s->this_mem);
 

hw/pci-host/pnv_phb3.c

@@ -968,6 +968,10 @@ static AddressSpace *pnv_phb3_dma_iommu(PCIBus *bus, void *opaque, int devfn)
     return &ds->dma_as;
 }
 
+static PCIIOMMUOps pnv_phb3_iommu_ops = {
+    .get_address_space = pnv_phb3_dma_iommu,
+};
+
 static void pnv_phb3_instance_init(Object *obj)
 {
     PnvPHB3 *phb = PNV_PHB3(obj);
@@ -1012,7 +1016,7 @@ void pnv_phb3_bus_init(DeviceState *dev, PnvPHB3 *phb)
     object_property_set_int(OBJECT(pci->bus), "chip-id", phb->chip_id,
                             &error_abort);
 
-    pci_setup_iommu(pci->bus, pnv_phb3_dma_iommu, phb);
+    pci_setup_iommu(pci->bus, &pnv_phb3_iommu_ops, phb);
 }
 
 static void pnv_phb3_realize(DeviceState *dev, Error **errp)

hw/pci-host/pnv_phb4.c

@@ -1518,6 +1518,10 @@ static void pnv_phb4_xscom_realize(PnvPHB4 *phb)
                             &phb->phb_regs_mr);
 }
 
+static PCIIOMMUOps pnv_phb4_iommu_ops = {
+    .get_address_space = pnv_phb4_dma_iommu,
+};
+
 static void pnv_phb4_instance_init(Object *obj)
 {
     PnvPHB4 *phb = PNV_PHB4(obj);
@@ -1557,7 +1561,7 @@ void pnv_phb4_bus_init(DeviceState *dev, PnvPHB4 *phb)
     object_property_set_int(OBJECT(pci->bus), "chip-id", phb->chip_id,
                             &error_abort);
 
-    pci_setup_iommu(pci->bus, pnv_phb4_dma_iommu, phb);
+    pci_setup_iommu(pci->bus, &pnv_phb4_iommu_ops, phb);
     pci->bus->flags |= PCI_BUS_EXTENDED_CONFIG_SPACE;
 }
 

hw/pci-host/ppce500.c

@@ -435,6 +435,10 @@ static AddressSpace *e500_pcihost_set_iommu(PCIBus *bus, void *opaque,
     return &s->bm_as;
 }
 
+static const PCIIOMMUOps ppce500_iommu_ops = {
+    .get_address_space = e500_pcihost_set_iommu,
+};
+
 static void e500_pcihost_realize(DeviceState *dev, Error **errp)
 {
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
@@ -469,7 +473,7 @@ static void e500_pcihost_realize(DeviceState *dev, Error **errp)
     memory_region_init(&s->bm, OBJECT(s), "bm-e500", UINT64_MAX);
     memory_region_add_subregion(&s->bm, 0x0, &s->busmem);
     address_space_init(&s->bm_as, &s->bm, "pci-bm");
-    pci_setup_iommu(b, e500_pcihost_set_iommu, s);
+    pci_setup_iommu(b, &ppce500_iommu_ops, s);
 
     pci_create_simple(b, 0, "e500-host-bridge");
 

hw/pci-host/raven.c

@@ -223,6 +223,10 @@ static AddressSpace *raven_pcihost_set_iommu(PCIBus *bus, void *opaque,
     return &s->bm_as;
 }
 
+static const PCIIOMMUOps raven_iommu_ops = {
+    .get_address_space = raven_pcihost_set_iommu,
+};
+
 static void raven_change_gpio(void *opaque, int n, int level)
 {
     PREPPCIState *s = opaque;
@@ -320,7 +324,7 @@ static void raven_pcihost_initfn(Object *obj)
     memory_region_add_subregion(&s->bm, 0         , &s->bm_pci_memory_alias);
     memory_region_add_subregion(&s->bm, 0x80000000, &s->bm_ram_alias);
     address_space_init(&s->bm_as, &s->bm, "raven-bm");
-    pci_setup_iommu(&s->pci_bus, raven_pcihost_set_iommu, s);
+    pci_setup_iommu(&s->pci_bus, &raven_iommu_ops, s);
 
     h->bus = &s->pci_bus;
 

hw/pci-host/sabre.c

@@ -112,6 +112,10 @@ static AddressSpace *sabre_pci_dma_iommu(PCIBus *bus, void *opaque, int devfn)
     return &is->iommu_as;
 }
 
+static const PCIIOMMUOps sabre_iommu_ops = {
+    .get_address_space = sabre_pci_dma_iommu,
+};
+
 static void sabre_config_write(void *opaque, hwaddr addr,
                                uint64_t val, unsigned size)
 {
@@ -384,7 +388,7 @@ static void sabre_realize(DeviceState *dev, Error **errp)
     /* IOMMU */
     memory_region_add_subregion_overlap(&s->sabre_config, 0x200,
                     sysbus_mmio_get_region(SYS_BUS_DEVICE(s->iommu), 0), 1);
-    pci_setup_iommu(phb->bus, sabre_pci_dma_iommu, s->iommu);
+    pci_setup_iommu(phb->bus, &sabre_iommu_ops, s->iommu);
 
     /* APB secondary busses */
     pci_dev = pci_new_multifunction(PCI_DEVFN(1, 0), TYPE_SIMBA_PCI_BRIDGE);

hw/pci/pci.c

@@ -2678,7 +2678,7 @@ AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
     PCIBus *iommu_bus = bus;
     uint8_t devfn = dev->devfn;
 
-    while (iommu_bus && !iommu_bus->iommu_fn && iommu_bus->parent_dev) {
+    while (iommu_bus && !iommu_bus->iommu_ops && iommu_bus->parent_dev) {
         PCIBus *parent_bus = pci_get_bus(iommu_bus->parent_dev);
 
         /*
@@ -2717,15 +2717,23 @@ AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
 
         iommu_bus = parent_bus;
     }
-    if (!pci_bus_bypass_iommu(bus) && iommu_bus && iommu_bus->iommu_fn) {
-        return iommu_bus->iommu_fn(bus, iommu_bus->iommu_opaque, devfn);
+    if (!pci_bus_bypass_iommu(bus) && iommu_bus->iommu_ops) {
+        return iommu_bus->iommu_ops->get_address_space(bus,
+                                 iommu_bus->iommu_opaque, devfn);
     }
     return &address_space_memory;
 }
 
-void pci_setup_iommu(PCIBus *bus, PCIIOMMUFunc fn, void *opaque)
+void pci_setup_iommu(PCIBus *bus, const PCIIOMMUOps *ops, void *opaque)
 {
-    bus->iommu_fn = fn;
+    /*
+     * If called, pci_setup_iommu() should provide a minimum set of
+     * useful callbacks for the bus.
+     */
+    assert(ops);
+    assert(ops->get_address_space);
+
+    bus->iommu_ops = ops;
     bus->iommu_opaque = opaque;
 }
 

hw/ppc/ppc440_pcix.c

@@ -449,6 +449,10 @@ static AddressSpace *ppc440_pcix_set_iommu(PCIBus *b, void *opaque, int devfn)
     return &s->bm_as;
 }
 
+static const PCIIOMMUOps ppc440_iommu_ops = {
+    .get_address_space = ppc440_pcix_set_iommu,
+};
+
 /*
  * Some guests on sam460ex write all kinds of garbage here such as
  * missing enable bit and low bits set and still expect this to work
@@ -503,7 +507,7 @@ static void ppc440_pcix_realize(DeviceState *dev, Error **errp)
     memory_region_init(&s->bm, OBJECT(s), "bm-ppc440-pcix", UINT64_MAX);
     memory_region_add_subregion(&s->bm, 0x0, &s->busmem);
     address_space_init(&s->bm_as, &s->bm, "pci-bm");
-    pci_setup_iommu(h->bus, ppc440_pcix_set_iommu, s);
+    pci_setup_iommu(h->bus, &ppc440_iommu_ops, s);
 
     memory_region_init(&s->container, OBJECT(s), "pci-container", PCI_ALL_SIZE);
     memory_region_init_io(&h->conf_mem, OBJECT(s), &ppc440_pcix_host_conf_ops,

hw/ppc/spapr_pci.c

@@ -780,6 +780,10 @@ static AddressSpace *spapr_pci_dma_iommu(PCIBus *bus, void *opaque, int devfn)
     return &phb->iommu_as;
 }
 
+static const PCIIOMMUOps spapr_iommu_ops = {
+    .get_address_space = spapr_pci_dma_iommu,
+};
+
 static char *spapr_phb_vfio_get_loc_code(SpaprPhbState *sphb,  PCIDevice *pdev)
 {
     g_autofree char *path = NULL;
@@ -1978,7 +1982,7 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp)
     memory_region_add_subregion(&sphb->iommu_root, SPAPR_PCI_MSI_WINDOW,
                                 &sphb->msiwindow);
 
-    pci_setup_iommu(bus, spapr_pci_dma_iommu, sphb);
+    pci_setup_iommu(bus, &spapr_iommu_ops, sphb);
 
     pci_bus_set_route_irq_fn(bus, spapr_route_intx_pin_to_irq);
 

hw/remote/iommu.c

@@ -100,6 +100,10 @@ static void remote_iommu_finalize(Object *obj)
     iommu->elem_by_devfn = NULL;
 }
 
+static const PCIIOMMUOps remote_iommu_ops = {
+    .get_address_space = remote_iommu_find_add_as,
+};
+
 void remote_iommu_setup(PCIBus *pci_bus)
 {
     RemoteIommu *iommu = NULL;
@@ -108,7 +112,7 @@ void remote_iommu_setup(PCIBus *pci_bus)
 
     iommu = REMOTE_IOMMU(object_new(TYPE_REMOTE_IOMMU));
 
-    pci_setup_iommu(pci_bus, remote_iommu_find_add_as, iommu);
+    pci_setup_iommu(pci_bus, &remote_iommu_ops, iommu);
 
     object_property_add_child(OBJECT(pci_bus), "remote-iommu", OBJECT(iommu));
 

hw/s390x/s390-pci-bus.c

@@ -652,6 +652,10 @@ static AddressSpace *s390_pci_dma_iommu(PCIBus *bus, void *opaque, int devfn)
     return &iommu->as;
 }
 
+static const PCIIOMMUOps s390_iommu_ops = {
+    .get_address_space = s390_pci_dma_iommu,
+};
+
 static uint8_t set_ind_atomic(uint64_t ind_loc, uint8_t to_be_set)
 {
     uint8_t expected, actual;
@@ -839,7 +843,7 @@ static void s390_pcihost_realize(DeviceState *dev, Error **errp)
     b = pci_register_root_bus(dev, NULL, s390_pci_set_irq, s390_pci_map_irq,
                               NULL, get_system_memory(), get_system_io(), 0,
                               64, TYPE_PCI_BUS);
-    pci_setup_iommu(b, s390_pci_dma_iommu, s);
+    pci_setup_iommu(b, &s390_iommu_ops, s);
 
     bus = BUS(b);
     qbus_set_hotplug_handler(bus, OBJECT(dev));
@@ -1058,7 +1062,7 @@ static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
 
         pdev = PCI_DEVICE(dev);
         pci_bridge_map_irq(pb, dev->id, s390_pci_map_irq);
-        pci_setup_iommu(&pb->sec_bus, s390_pci_dma_iommu, s);
+        pci_setup_iommu(&pb->sec_bus, &s390_iommu_ops, s);
 
         qbus_set_hotplug_handler(BUS(&pb->sec_bus), OBJECT(s));
 

hw/virtio/virtio-iommu.c

@@ -461,6 +461,10 @@ static AddressSpace *virtio_iommu_find_add_as(PCIBus *bus, void *opaque,
     return &sdev->as;
 }
 
+static const PCIIOMMUOps virtio_iommu_ops = {
+    .get_address_space = virtio_iommu_find_add_as,
+};
+
 static int virtio_iommu_attach(VirtIOIOMMU *s,
                                struct virtio_iommu_req_attach *req)
 {
@@ -1332,7 +1336,7 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
     s->as_by_busptr = g_hash_table_new_full(NULL, NULL, NULL, g_free);
 
     if (s->primary_bus) {
-        pci_setup_iommu(s->primary_bus, virtio_iommu_find_add_as, s);
+        pci_setup_iommu(s->primary_bus, &virtio_iommu_ops, s);
     } else {
         error_setg(errp, "VIRTIO-IOMMU is not attached to any PCI bus!");
     }

include/hw/pci/pci.h

@@ -363,10 +363,42 @@ void pci_bus_get_w64_range(PCIBus *bus, Range *range);
 
 void pci_device_deassert_intx(PCIDevice *dev);
 
-typedef AddressSpace *(*PCIIOMMUFunc)(PCIBus *, void *, int);
+
+/**
+ * struct PCIIOMMUOps: callbacks structure for specific IOMMU handlers
+ * of a PCIBus
+ *
+ * Allows to modify the behavior of some IOMMU operations of the PCI
+ * framework for a set of devices on a PCI bus.
+ */
+typedef struct PCIIOMMUOps {
+    /**
+     * @get_address_space: get the address space for a set of devices
+     * on a PCI bus.
+     *
+     * Mandatory callback which returns a pointer to an #AddressSpace
+     *
+     * @bus: the #PCIBus being accessed.
+     *
+     * @opaque: the data passed to pci_setup_iommu().
+     *
+     * @devfn: device and function number
+     */
+   AddressSpace * (*get_address_space)(PCIBus *bus, void *opaque, int devfn);
+} PCIIOMMUOps;
 
 AddressSpace *pci_device_iommu_address_space(PCIDevice *dev);
-void pci_setup_iommu(PCIBus *bus, PCIIOMMUFunc fn, void *opaque);
+
+/**
+ * pci_setup_iommu: Initialize specific IOMMU handlers for a PCIBus
+ *
+ * Let PCI host bridges define specific operations.
+ *
+ * @bus: the #PCIBus being updated.
+ * @ops: the #PCIIOMMUOps
+ * @opaque: passed to callbacks of the @ops structure.
+ */
+void pci_setup_iommu(PCIBus *bus, const PCIIOMMUOps *ops, void *opaque);
 
 pcibus_t pci_bar_address(PCIDevice *d,
                          int reg, uint8_t type, pcibus_t size);

include/hw/pci/pci_bus.h

@@ -33,7 +33,7 @@ enum PCIBusFlags {
 struct PCIBus {
     BusState qbus;
     enum PCIBusFlags flags;
-    PCIIOMMUFunc iommu_fn;
+    const PCIIOMMUOps *iommu_ops;
     void *iommu_opaque;
     uint8_t devfn_min;
     uint32_t slot_reserved_mask;