[PATCH v16 03/10] virtio-iommu: Implement attach/detach command

[Eric Auger]

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 <address@hidden>
Reviewed-by: Peter Xu <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>

---
v14 -> v15:
- destroy mappings in put_domain and remove
  g_tree_destroy(domain->mappings) in virtio_iommu_detach

v13 -> v14:
- in virtio_iommu_put_endpoint, if the EP is attached to a
  domain, call virtio_iommu_detach_endpoint_from_domain()
- remove domain ref counting and simply delete the mappings
  gtree when the last EP is detached from the domain
- in virtio_iommu_detach_endpoint_from_domain(), return if the
  ep's domain is unset.

v12 -> v13:
- squashed v12 4, 5, 6 into this patch
- rename virtio_iommu_get_sid into virtio_iommu_get_bdf

v11 -> v12:
- check the device is protected by the iommu on attach
- on detach, check the domain id the device is attached to matches
  the one used in the detach command
- fix mapping ref counter and destroy the domain when no end-points
  are attached anymore
---
 hw/virtio/trace-events           |   6 +
 hw/virtio/virtio-iommu.c         | 311 ++++++++++++++++++++++++++++++-
 include/hw/virtio/virtio-iommu.h |   3 +
 3 files changed, 318 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
index f7141aa2f6..15595f8cd7 100644
--- a/hw/virtio/trace-events
+++ b/hw/virtio/trace-events
@@ -64,3 +64,9 @@ virtio_iommu_attach(uint32_t domain_id, uint32_t ep_id) 
"domain=%d endpoint=%d"
 virtio_iommu_detach(uint32_t domain_id, uint32_t ep_id) "domain=%d endpoint=%d"
 virtio_iommu_map(uint32_t domain_id, uint64_t virt_start, uint64_t virt_end, 
uint64_t phys_start, uint32_t flags) "domain=%d virt_start=0x%"PRIx64" 
virt_end=0x%"PRIx64 " phys_start=0x%"PRIx64" flags=%d"
 virtio_iommu_unmap(uint32_t domain_id, uint64_t virt_start, uint64_t virt_end) 
"domain=%d virt_start=0x%"PRIx64" virt_end=0x%"PRIx64
+virtio_iommu_translate(const char *name, uint32_t rid, uint64_t iova, int 
flag) "mr=%s rid=%d addr=0x%"PRIx64" flag=%d"
+virtio_iommu_init_iommu_mr(char *iommu_mr) "init %s"
+virtio_iommu_get_endpoint(uint32_t ep_id) "Alloc endpoint=%d"
+virtio_iommu_put_endpoint(uint32_t ep_id) "Free endpoint=%d"
+virtio_iommu_get_domain(uint32_t domain_id) "Alloc domain=%d"
+virtio_iommu_put_domain(uint32_t domain_id) "Free domain=%d"
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)
diff --git a/include/hw/virtio/virtio-iommu.h b/include/hw/virtio/virtio-iommu.h
index d24ba63305..ae88f730cf 100644
--- a/include/hw/virtio/virtio-iommu.h
+++ b/include/hw/virtio/virtio-iommu.h
@@ -28,6 +28,8 @@
 #define VIRTIO_IOMMU(obj) \
         OBJECT_CHECK(VirtIOIOMMU, (obj), TYPE_VIRTIO_IOMMU)
 
+#define TYPE_VIRTIO_IOMMU_MEMORY_REGION "virtio-iommu-memory-region"
+
 typedef struct IOMMUDevice {
     void         *viommu;
     PCIBus       *bus;
@@ -48,6 +50,7 @@ typedef struct VirtIOIOMMU {
     struct virtio_iommu_config config;
     uint64_t features;
     GHashTable *as_by_busptr;
+    IOMMUPciBus *iommu_pcibus_by_bus_num[PCI_BUS_MAX];
     PCIBus *primary_bus;
     GTree *domains;
     QemuMutex mutex;
-- 
2.20.1