[Qemu-devel] [RFC PATCH 8/8] iommu: introduce hw/core/iommu

[Peter Xu <peterx@redhat.com>]

Time to consider a common stuff for IOMMU. Let's start from an common
IOMMU object (which should be inlayed in custom IOMMU implementations)
and a notifier mechanism.

Let VT-d IOMMU be the first user.

An example to use this per-iommu notifier:

  (when registering)
  iommu = address_space_iommu_get(pci_device_iommu_address_space(dev));
  notifier = iommu_notifier_register(iommu, IOMMU_EVENT_SVM_PASID, func);
  ...
  (when notify)
  IOMMUEvent event = { .type = IOMMU_EVENT_SVM_PASID ... };
  iommu_notify(iommu, &event);
  ...
  (when releasing)
  iommu_notifier_unregister(notifier);
  notifier = NULL;

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/core/Makefile.objs         |  1 +
 hw/core/iommu.c               | 61 ++++++++++++++++++++++++++++++++++++
 hw/i386/intel_iommu.c         |  2 +-
 include/exec/memory.h         | 10 +-----
 include/hw/core/iommu.h       | 72 +++++++++++++++++++++++++++++++++++++++++++
 include/hw/i386/intel_iommu.h |  2 ++
 6 files changed, 138 insertions(+), 10 deletions(-)
 create mode 100644 hw/core/iommu.c
 create mode 100644 include/hw/core/iommu.h

diff --git a/hw/core/Makefile.objs b/hw/core/Makefile.objs
index 91450b2..85cca44 100644
--- a/hw/core/Makefile.objs
+++ b/hw/core/Makefile.objs
@@ -5,6 +5,7 @@ common-obj-y += fw-path-provider.o
 # irq.o needed for qdev GPIO handling:
 common-obj-y += irq.o
 common-obj-y += hotplug.o
+common-obj-y += iommu.o
 obj-y += nmi.o
 
 common-obj-$(CONFIG_EMPTY_SLOT) += empty_slot.o
diff --git a/hw/core/iommu.c b/hw/core/iommu.c
new file mode 100644
index 0000000..e014e96
--- /dev/null
+++ b/hw/core/iommu.c
@@ -0,0 +1,61 @@
+/*
+ * QEMU emulation of IOMMU logic
+ *
+ * Copyright (C) 2017 Red Hat Inc.
+ *
+ * Authors: Peter Xu <peterx@redhat.com>,
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/core/iommu.h"
+
+IOMMUNotifier *iommu_notifier_register(IOMMUObject *iommu,
+                                       IOMMUNotifyFn fn,
+                                       uint64_t event_mask)
+{
+    IOMMUNotifier *notifier = g_new0(IOMMUNotifier, 1);
+
+    assert((event_mask & ~IOMMU_EVENT_MASK) == 0);
+    notifier->event_mask = event_mask;
+    notifier->iommu_notify = fn;
+    QLIST_INSERT_HEAD(&iommu->iommu_notifiers, notifier, node);
+
+    return notifier;
+}
+
+void iommu_notifier_unregister(IOMMUObject *iommu,
+                               IOMMUNotifier *notifier)
+{
+    IOMMUNotifier *cur, *next;
+
+    QLIST_FOREACH_SAFE(cur, &iommu->iommu_notifiers, node, next) {
+        if (cur == notifier) {
+            QLIST_REMOVE(cur, node);
+            break;
+        }
+    }
+}
+
+void iommu_notify(IOMMUObject *iommu, IOMMUEvent *event)
+{
+    IOMMUNotifier *cur;
+
+    QLIST_FOREACH(cur, &iommu->iommu_notifiers, node) {
+        if (cur->event_mask & event->type && cur->iommu_notify) {
+            cur->iommu_notify(cur, event);
+        }
+    }
+}
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 5131329..d6f6701 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -2635,7 +2635,7 @@ static const MemoryRegionOps vtd_mem_ir_ops = {
 static IOMMUObject *vtd_as_iommu_get(AddressSpace *as)
 {
     VTDAddressSpace *vtd_dev_as = container_of(as, VTDAddressSpace, as);
-    return (IOMMUObject *)vtd_dev_as->iommu_state;
+    return &vtd_dev_as->iommu_state->iommu_common;
 }
 
 VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus, int devfn)
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 0b0b58b..5ca1dd0 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -27,6 +27,7 @@
 #include "qemu/notify.h"
 #include "qom/object.h"
 #include "qemu/rcu.h"
+#include "hw/core/iommu.h"
 
 #define RAM_ADDR_INVALID (~(ram_addr_t)0)
 
@@ -183,15 +184,6 @@ struct MemoryRegionOps {
     const MemoryRegionMmio old_mmio;
 };
 
-/*
- * This stands for an IOMMU unit. Normally it should be exactly the
- * IOMMU device, however this can also be actually anything which is
- * related to that translation unit. What it is should be totally
- * arch-dependent. Maybe one day we can have something better than a
- * (void *) here.
- */
-typedef void *IOMMUObject;
-
 typedef struct MemoryRegionIOMMUOps MemoryRegionIOMMUOps;
 
 struct MemoryRegionIOMMUOps {
diff --git a/include/hw/core/iommu.h b/include/hw/core/iommu.h
new file mode 100644
index 0000000..16e6adf
--- /dev/null
+++ b/include/hw/core/iommu.h
@@ -0,0 +1,72 @@
+/*
+ * QEMU emulation of IOMMU logic
+ *
+ * Copyright (C) 2017 Red Hat Inc.
+ *
+ * Authors: Peter Xu <peterx@redhat.com>,
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __PCI_IOMMU_H__
+#define __PCI_IOMMU_H__
+
+#include "qemu/queue.h"
+
+#define IOMMU_EVENT_SVM_PASID      (0)
+#define IOMMU_EVENT_MASK           (IOMMU_EVENT_SVM_PASID)
+
+struct IOMMUEvent {
+    uint64_t type;
+    union {
+        struct {
+            /* TODO: fill in correct stuff. */
+            int value;
+        } svm;
+    } data;
+};
+typedef struct IOMMUEvent IOMMUEvent;
+
+typedef struct IOMMUNotifier IOMMUNotifier;
+
+typedef void (*IOMMUNotifyFn)(IOMMUNotifier *notifier, IOMMUEvent *event);
+
+struct IOMMUNotifier {
+    IOMMUNotifyFn iommu_notify;
+    /*
+     * What events we are listening to. Let's allow multiple event
+     * registrations from beginning.
+     */
+    uint64_t event_mask;
+    QLIST_ENTRY(IOMMUNotifier) node;
+};
+
+/*
+ * This stands for an IOMMU unit. Any translation device should have
+ * this struct inside its own structure to make sure it can leverage
+ * common IOMMU functionalities.
+ */
+struct IOMMUObject {
+    QLIST_HEAD(, IOMMUNotifier) iommu_notifiers;
+};
+typedef struct IOMMUObject IOMMUObject;
+
+IOMMUNotifier *iommu_notifier_register(IOMMUObject *iommu,
+                                       IOMMUNotifyFn fn,
+                                       uint64_t event_mask);
+void iommu_notifier_unregister(IOMMUObject *iommu,
+                               IOMMUNotifier *notifier);
+void iommu_notify(IOMMUObject *iommu, IOMMUEvent *event);
+
+#endif
diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index f9ac0ec..ec696f5 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -26,6 +26,7 @@
 #include "hw/i386/x86-iommu.h"
 #include "hw/i386/ioapic.h"
 #include "hw/pci/msi.h"
+#include "hw/core/iommu.h"
 #include "hw/sysbus.h"
 
 #define TYPE_INTEL_IOMMU_DEVICE "intel-iommu"
@@ -258,6 +259,7 @@ struct IntelIOMMUMRNotifierNode {
 /* The iommu (DMAR) device state struct */
 struct IntelIOMMUState {
     X86IOMMUState x86_iommu;
+    IOMMUObject iommu_common;
     MemoryRegion csrmem;
     uint8_t csr[DMAR_REG_SIZE];     /* register values */
     uint8_t wmask[DMAR_REG_SIZE];   /* R/W bytes */
-- 
2.7.4