virtio-iommu: Implement attach/detach command

This patch implements the endpoint attach/detach to/from
a domain.

Domain and endpoint internal datatypes are introduced.
Both are stored in RB trees. The domain owns a list of
endpoints attached to it. Also helpers to get/put
end points and domains are introduced.

As for the IOMMU memory regions, a callback is called on
PCI bus enumeration that initializes for a given device
on the bus hierarchy an IOMMU memory region. The PCI bus
hierarchy is stored locally in IOMMUPciBus and IOMMUDevice
objects.

At the time of the enumeration, the bus number may not be
computed yet.

So operations that will need to retrieve the IOMMUdevice
and its IOMMU memory region from the bus number and devfn,
once the bus number is garanteed to be frozen, use an array
of IOMMUPciBus, lazily populated.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

Message-Id: <20200214132745.23392-4-eric.auger@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 309 insertions, 2 deletions

diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 86dcdc09a1..d9fe83f530 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -23,6 +23,8 @@
 #include "hw/qdev-properties.h"
 #include "hw/virtio/virtio.h"
 #include "sysemu/kvm.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
 #include "trace.h"
 
 #include "standard-headers/linux/virtio_ids.h"
@@ -30,19 +32,236 @@
 #include "hw/virtio/virtio-bus.h"
 #include "hw/virtio/virtio-access.h"
 #include "hw/virtio/virtio-iommu.h"
+#include "hw/pci/pci_bus.h"
+#include "hw/pci/pci.h"
 
 /* Max size */
 #define VIOMMU_DEFAULT_QUEUE_SIZE 256
 
+typedef struct VirtIOIOMMUDomain {
+    uint32_t id;
+    GTree *mappings;
+    QLIST_HEAD(, VirtIOIOMMUEndpoint) endpoint_list;
+} VirtIOIOMMUDomain;
+
+typedef struct VirtIOIOMMUEndpoint {
+    uint32_t id;
+    VirtIOIOMMUDomain *domain;
+    QLIST_ENTRY(VirtIOIOMMUEndpoint) next;
+} VirtIOIOMMUEndpoint;
+
+typedef struct VirtIOIOMMUInterval {
+    uint64_t low;
+    uint64_t high;
+} VirtIOIOMMUInterval;
+
+static inline uint16_t virtio_iommu_get_bdf(IOMMUDevice *dev)
+{
+    return PCI_BUILD_BDF(pci_bus_num(dev->bus), dev->devfn);
+}
+
+/**
+ * The bus number is used for lookup when SID based operations occur.
+ * In that case we lazily populate the IOMMUPciBus array from the bus hash
+ * table. At the time the IOMMUPciBus is created (iommu_find_add_as), the bus
+ * numbers may not be always initialized yet.
+ */
+static IOMMUPciBus *iommu_find_iommu_pcibus(VirtIOIOMMU *s, uint8_t bus_num)
+{
+    IOMMUPciBus *iommu_pci_bus = s->iommu_pcibus_by_bus_num[bus_num];
+
+    if (!iommu_pci_bus) {
+        GHashTableIter iter;
+
+        g_hash_table_iter_init(&iter, s->as_by_busptr);
+        while (g_hash_table_iter_next(&iter, NULL, (void **)&iommu_pci_bus)) {
+            if (pci_bus_num(iommu_pci_bus->bus) == bus_num) {
+                s->iommu_pcibus_by_bus_num[bus_num] = iommu_pci_bus;
+                return iommu_pci_bus;
+            }
+        }
+        return NULL;
+    }
+    return iommu_pci_bus;
+}
+
+static IOMMUMemoryRegion *virtio_iommu_mr(VirtIOIOMMU *s, uint32_t sid)
+{
+    uint8_t bus_n, devfn;
+    IOMMUPciBus *iommu_pci_bus;
+    IOMMUDevice *dev;
+
+    bus_n = PCI_BUS_NUM(sid);
+    iommu_pci_bus = iommu_find_iommu_pcibus(s, bus_n);
+    if (iommu_pci_bus) {
+        devfn = sid & PCI_DEVFN_MAX;
+        dev = iommu_pci_bus->pbdev[devfn];
+        if (dev) {
+            return &dev->iommu_mr;
+        }
+    }
+    return NULL;
+}
+
+static gint interval_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
+{
+    VirtIOIOMMUInterval *inta = (VirtIOIOMMUInterval *)a;
+    VirtIOIOMMUInterval *intb = (VirtIOIOMMUInterval *)b;
+
+    if (inta->high < intb->low) {
+        return -1;
+    } else if (intb->high < inta->low) {
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+static void virtio_iommu_detach_endpoint_from_domain(VirtIOIOMMUEndpoint *ep)
+{
+    if (!ep->domain) {
+        return;
+    }
+    QLIST_REMOVE(ep, next);
+    ep->domain = NULL;
+}
+
+static VirtIOIOMMUEndpoint *virtio_iommu_get_endpoint(VirtIOIOMMU *s,
+                                                      uint32_t ep_id)
+{
+    VirtIOIOMMUEndpoint *ep;
+
+    ep = g_tree_lookup(s->endpoints, GUINT_TO_POINTER(ep_id));
+    if (ep) {
+        return ep;
+    }
+    if (!virtio_iommu_mr(s, ep_id)) {
+        return NULL;
+    }
+    ep = g_malloc0(sizeof(*ep));
+    ep->id = ep_id;
+    trace_virtio_iommu_get_endpoint(ep_id);
+    g_tree_insert(s->endpoints, GUINT_TO_POINTER(ep_id), ep);
+    return ep;
+}
+
+static void virtio_iommu_put_endpoint(gpointer data)
+{
+    VirtIOIOMMUEndpoint *ep = (VirtIOIOMMUEndpoint *)data;
+
+    if (ep->domain) {
+        virtio_iommu_detach_endpoint_from_domain(ep);
+    }
+
+    trace_virtio_iommu_put_endpoint(ep->id);
+    g_free(ep);
+}
+
+static VirtIOIOMMUDomain *virtio_iommu_get_domain(VirtIOIOMMU *s,
+                                                  uint32_t domain_id)
+{
+    VirtIOIOMMUDomain *domain;
+
+    domain = g_tree_lookup(s->domains, GUINT_TO_POINTER(domain_id));
+    if (domain) {
+        return domain;
+    }
+    domain = g_malloc0(sizeof(*domain));
+    domain->id = domain_id;
+    domain->mappings = g_tree_new_full((GCompareDataFunc)interval_cmp,
+                                   NULL, (GDestroyNotify)g_free,
+                                   (GDestroyNotify)g_free);
+    g_tree_insert(s->domains, GUINT_TO_POINTER(domain_id), domain);
+    QLIST_INIT(&domain->endpoint_list);
+    trace_virtio_iommu_get_domain(domain_id);
+    return domain;
+}
+
+static void virtio_iommu_put_domain(gpointer data)
+{
+    VirtIOIOMMUDomain *domain = (VirtIOIOMMUDomain *)data;
+    VirtIOIOMMUEndpoint *iter, *tmp;
+
+    QLIST_FOREACH_SAFE(iter, &domain->endpoint_list, next, tmp) {
+        virtio_iommu_detach_endpoint_from_domain(iter);
+    }
+    g_tree_destroy(domain->mappings);
+    trace_virtio_iommu_put_domain(domain->id);
+    g_free(domain);
+}
+
+static AddressSpace *virtio_iommu_find_add_as(PCIBus *bus, void *opaque,
+                                              int devfn)
+{
+    VirtIOIOMMU *s = opaque;
+    IOMMUPciBus *sbus = g_hash_table_lookup(s->as_by_busptr, bus);
+    static uint32_t mr_index;
+    IOMMUDevice *sdev;
+
+    if (!sbus) {
+        sbus = g_malloc0(sizeof(IOMMUPciBus) +
+                         sizeof(IOMMUDevice *) * PCI_DEVFN_MAX);
+        sbus->bus = bus;
+        g_hash_table_insert(s->as_by_busptr, bus, sbus);
+    }
+
+    sdev = sbus->pbdev[devfn];
+    if (!sdev) {
+        char *name = g_strdup_printf("%s-%d-%d",
+                                     TYPE_VIRTIO_IOMMU_MEMORY_REGION,
+                                     mr_index++, devfn);
+        sdev = sbus->pbdev[devfn] = g_malloc0(sizeof(IOMMUDevice));
+
+        sdev->viommu = s;
+        sdev->bus = bus;
+        sdev->devfn = devfn;
+
+        trace_virtio_iommu_init_iommu_mr(name);
+
+        memory_region_init_iommu(&sdev->iommu_mr, sizeof(sdev->iommu_mr),
+                                 TYPE_VIRTIO_IOMMU_MEMORY_REGION,
+                                 OBJECT(s), name,
+                                 UINT64_MAX);
+        address_space_init(&sdev->as,
+                           MEMORY_REGION(&sdev->iommu_mr), TYPE_VIRTIO_IOMMU);
+        g_free(name);
+    }
+    return &sdev->as;
+}
+
 static int virtio_iommu_attach(VirtIOIOMMU *s,
                                struct virtio_iommu_req_attach *req)
 {
     uint32_t domain_id = le32_to_cpu(req->domain);
     uint32_t ep_id = le32_to_cpu(req->endpoint);
+    VirtIOIOMMUDomain *domain;
+    VirtIOIOMMUEndpoint *ep;
 
     trace_virtio_iommu_attach(domain_id, ep_id);
 
-    return VIRTIO_IOMMU_S_UNSUPP;
+    ep = virtio_iommu_get_endpoint(s, ep_id);
+    if (!ep) {
+        return VIRTIO_IOMMU_S_NOENT;
+    }
+
+    if (ep->domain) {
+        VirtIOIOMMUDomain *previous_domain = ep->domain;
+        /*
+         * the device is already attached to a domain,
+         * detach it first
+         */
+        virtio_iommu_detach_endpoint_from_domain(ep);
+        if (QLIST_EMPTY(&previous_domain->endpoint_list)) {
+            g_tree_remove(s->domains, GUINT_TO_POINTER(previous_domain->id));
+        }
+    }
+
+    domain = virtio_iommu_get_domain(s, domain_id);
+    QLIST_INSERT_HEAD(&domain->endpoint_list, ep, next);
+
+    ep->domain = domain;
+
+    return VIRTIO_IOMMU_S_OK;
 }
 
 static int virtio_iommu_detach(VirtIOIOMMU *s,
@@ -50,10 +269,28 @@ static int virtio_iommu_detach(VirtIOIOMMU *s,
 {
     uint32_t domain_id = le32_to_cpu(req->domain);
     uint32_t ep_id = le32_to_cpu(req->endpoint);
+    VirtIOIOMMUDomain *domain;
+    VirtIOIOMMUEndpoint *ep;
 
     trace_virtio_iommu_detach(domain_id, ep_id);
 
-    return VIRTIO_IOMMU_S_UNSUPP;
+    ep = g_tree_lookup(s->endpoints, GUINT_TO_POINTER(ep_id));
+    if (!ep) {
+        return VIRTIO_IOMMU_S_NOENT;
+    }
+
+    domain = ep->domain;
+
+    if (!domain || domain->id != domain_id) {
+        return VIRTIO_IOMMU_S_INVAL;
+    }
+
+    virtio_iommu_detach_endpoint_from_domain(ep);
+
+    if (QLIST_EMPTY(&domain->endpoint_list)) {
+        g_tree_remove(s->domains, GUINT_TO_POINTER(domain->id));
+    }
+    return VIRTIO_IOMMU_S_OK;
 }
 
 static int virtio_iommu_map(VirtIOIOMMU *s,
@@ -172,6 +409,27 @@ out:
     }
 }
 
+static IOMMUTLBEntry virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr,
+                                            IOMMUAccessFlags flag,
+                                            int iommu_idx)
+{
+    IOMMUDevice *sdev = container_of(mr, IOMMUDevice, iommu_mr);
+    uint32_t sid;
+
+    IOMMUTLBEntry entry = {
+        .target_as = &address_space_memory,
+        .iova = addr,
+        .translated_addr = addr,
+        .addr_mask = ~(hwaddr)0,
+        .perm = IOMMU_NONE,
+    };
+
+    sid = virtio_iommu_get_bdf(sdev);
+
+    trace_virtio_iommu_translate(mr->parent_obj.name, sid, addr, flag);
+    return entry;
+}
+
 static void virtio_iommu_get_config(VirtIODevice *vdev, uint8_t *config_data)
 {
     VirtIOIOMMU *dev = VIRTIO_IOMMU(vdev);
@@ -218,6 +476,13 @@ static const VMStateDescription vmstate_virtio_iommu_device = {
     .unmigratable = 1,
 };
 
+static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
+{
+    guint ua = GPOINTER_TO_UINT(a);
+    guint ub = GPOINTER_TO_UINT(b);
+    return (ua > ub) - (ua < ub);
+}
+
 static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
@@ -226,6 +491,8 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
     virtio_init(vdev, "virtio-iommu", VIRTIO_ID_IOMMU,
                 sizeof(struct virtio_iommu_config));
 
+    memset(s->iommu_pcibus_by_bus_num, 0, sizeof(s->iommu_pcibus_by_bus_num));
+
     s->req_vq = virtio_add_queue(vdev, VIOMMU_DEFAULT_QUEUE_SIZE,
                              virtio_iommu_handle_command);
     s->event_vq = virtio_add_queue(vdev, VIOMMU_DEFAULT_QUEUE_SIZE, NULL);
@@ -244,18 +511,43 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
     virtio_add_feature(&s->features, VIRTIO_IOMMU_F_MMIO);
 
     qemu_mutex_init(&s->mutex);
+
+    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);
+    } else {
+        error_setg(errp, "VIRTIO-IOMMU is not attached to any PCI bus!");
+    }
 }
 
 static void virtio_iommu_device_unrealize(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VirtIOIOMMU *s = VIRTIO_IOMMU(dev);
+
+    g_tree_destroy(s->domains);
+    g_tree_destroy(s->endpoints);
 
     virtio_cleanup(vdev);
 }
 
 static void virtio_iommu_device_reset(VirtIODevice *vdev)
 {
+    VirtIOIOMMU *s = VIRTIO_IOMMU(vdev);
+
     trace_virtio_iommu_device_reset();
+
+    if (s->domains) {
+        g_tree_destroy(s->domains);
+    }
+    if (s->endpoints) {
+        g_tree_destroy(s->endpoints);
+    }
+    s->domains = g_tree_new_full((GCompareDataFunc)int_cmp,
+                                 NULL, NULL, virtio_iommu_put_domain);
+    s->endpoints = g_tree_new_full((GCompareDataFunc)int_cmp,
+                                   NULL, NULL, virtio_iommu_put_endpoint);
 }
 
 static void virtio_iommu_set_status(VirtIODevice *vdev, uint8_t status)
@@ -301,6 +593,14 @@ static void virtio_iommu_class_init(ObjectClass *klass, void *data)
     vdc->vmsd = &vmstate_virtio_iommu_device;
 }
 
+static void virtio_iommu_memory_region_class_init(ObjectClass *klass,
+                                                  void *data)
+{
+    IOMMUMemoryRegionClass *imrc = IOMMU_MEMORY_REGION_CLASS(klass);
+
+    imrc->translate = virtio_iommu_translate;
+}
+
 static const TypeInfo virtio_iommu_info = {
     .name = TYPE_VIRTIO_IOMMU,
     .parent = TYPE_VIRTIO_DEVICE,
@@ -309,9 +609,16 @@ static const TypeInfo virtio_iommu_info = {
     .class_init = virtio_iommu_class_init,
 };
 
+static const TypeInfo virtio_iommu_memory_region_info = {
+    .parent = TYPE_IOMMU_MEMORY_REGION,
+    .name = TYPE_VIRTIO_IOMMU_MEMORY_REGION,
+    .class_init = virtio_iommu_memory_region_class_init,
+};
+
 static void virtio_register_types(void)
 {
     type_register_static(&virtio_iommu_info);
+    type_register_static(&virtio_iommu_memory_region_info);
 }
 
 type_init(virtio_register_types)