kvm, arm, dev: Add an in-kernel GIC implementation

This changeset adds a GIC implementation that uses the kernel's
built-in support for simulating the interrupt controller. Since there
is currently no support for state transfer between gem5 and the
kernel, the device model does not support serialization and CPU
switching (which would require switching to a gem5-simulated GIC).

5 files changed, 280 insertions, 2 deletions

diff --git a/src/cpu/kvm/SConscript b/src/cpu/kvm/SConscript
index 8094cc585..5bb7580be 100644
--- a/src/cpu/kvm/SConscript
+++ b/src/cpu/kvm/SConscript
@@ -44,6 +44,7 @@ if env['USE_KVM']:
     SimObject('BaseKvmCPU.py')
 
     Source('base.cc')
+    Source('device.cc')
     Source('vm.cc')
     Source('perfevent.cc')
     Source('timer.cc')
diff --git a/src/cpu/kvm/device.cc b/src/cpu/kvm/device.cc
new file mode 100644
index 000000000..973bbaa64
--- /dev/null
+++ b/src/cpu/kvm/device.cc
@@ -0,0 +1,125 @@
+/*
+ * Copyright (c) 2015 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Andreas Sandberg
+ */
+
+#include "cpu/kvm/device.hh"
+
+#include <linux/kvm.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include <cassert>
+#include <cerrno>
+
+#include "base/misc.hh"
+
+KvmDevice::KvmDevice(int _fd)
+    : fd(_fd)
+{
+}
+
+KvmDevice::~KvmDevice()
+{
+    close(fd);
+}
+
+void
+KvmDevice::getAttrPtr(uint32_t group, uint64_t attr, void *data) const
+{
+#ifdef KVM_GET_DEVICE_ATTR
+  struct kvm_device_attr dattr = {
+        0, // Flags
+        group,
+        attr,
+        reinterpret_cast<uint64_t>(data),
+    };
+
+    if (ioctl(KVM_GET_DEVICE_ATTR, &dattr) == -1) {
+        panic("Failed to get attribute (group: %i, attr: %i, errno: %i)",
+              group, attr, errno);
+    }
+#else
+    panic("Kernel headers don't support KVM_GET_DEVICE_ATTR\n");
+#endif
+}
+
+void
+KvmDevice::setAttrPtr(uint32_t group, uint64_t attr, const void *data) const
+{
+#ifdef KVM_SET_DEVICE_ATTR
+    struct kvm_device_attr dattr = {
+        0, // Flags
+        group,
+        attr,
+        reinterpret_cast<uint64_t>(data),
+    };
+
+    if (ioctl(KVM_SET_DEVICE_ATTR, &dattr) == -1) {
+        panic("Failed to set attribute (group: %i, attr: %i, errno: %i)",
+              group, attr, errno);
+    }
+#else
+    panic("Kernel headers don't support KVM_GET_DEVICE_ATTR\n");
+#endif
+}
+
+bool
+KvmDevice::hasAttr(uint32_t group, uint64_t attr) const
+{
+#ifdef KVM_HAS_DEVICE_ATTR
+    struct kvm_device_attr dattr = {
+        0, // Flags
+        group,
+        attr,
+        0, // Data address (ignored)
+    };
+
+    return ioctl(KVM_HAS_DEVICE_ATTR, &dattr) == 0;
+#else
+    panic("Kernel headers don't support KVM_HAS_DEVICE_ATTR\n");
+#endif
+}
+
+int
+KvmDevice::ioctl(int request, long p1) const
+{
+    assert(fd != -1);
+
+    return ::ioctl(fd, request, p1);
+}
+
diff --git a/src/cpu/kvm/device.hh b/src/cpu/kvm/device.hh
new file mode 100644
index 000000000..01160f010
--- /dev/null
+++ b/src/cpu/kvm/device.hh
@@ -0,0 +1,126 @@
+/*
+ * Copyright (c) 2015 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Andreas Sandberg
+ */
+
+#ifndef __CPU_KVM_DEVICE_HH__
+#define __CPU_KVM_DEVICE_HH__
+
+#include <cstdint>
+
+/**
+ * KVM device wrapper
+ *
+ * This is a wrapper around a device emulated by KVM. Such devices can
+ * be created using KvmVM::createDevice() API. They are typically used
+ * for in-kernel interrupt controllers and similar devices.
+ *
+ * Each device has a device-specific set of attributes which are
+ * mapped into groups. The available attributes are described in the
+ * device's documentation in the kernel source tree
+ * (Documentation/virtual/kvm/devices/). Each attribute can be
+ * accessed with the getAttr() and setAttr() access methods. The
+ * presence of an attribute can be queried using the hasAttr() method.
+ */
+class KvmDevice
+{
+  public:
+    KvmDevice(int fd);
+    virtual ~KvmDevice();
+
+  public:
+    /**
+     * Get the value of an attribute
+     *
+     * See KVM's documentation, and specifically the device-specific
+     * documentation, for available attributes and attribute groups.
+     *
+     * @param group Attribute group
+     * @param attr Attribute ID within group
+     * @return Attribute value
+     */
+    template<typename T>
+    T getAttr(uint32_t group, uint64_t attr) const {
+        T data;
+        getAttrPtr(group, attr, &data);
+        return data;
+    }
+
+    /**
+     * Get the value of an attribute
+     *
+     * See KVM's documentation, and specifically the device-specific
+     * documentation, for available attributes and attribute groups.
+     *
+     * @param group Attribute group
+     * @param attr Attribute ID within group
+     * @return Attribute value
+     */
+    template<typename T>
+    void setAttr(uint32_t group, uint64_t attr, const T &data) const {
+        setAttrPtr(group, attr, &data);
+    }
+
+    void getAttrPtr(uint32_t group, uint64_t attr, void *data) const;
+    void setAttrPtr(uint32_t group, uint64_t attr, const void *data) const;
+
+    /**
+     * Check if a device attribute is valid
+     *
+     * See KVM's documentation, and specifically the device-specific
+     * documentation, for available attributes and attribute groups.
+     *
+     * @param group Attribute group
+     * @param attr Attribute ID within group
+     * @return true if attribute is valid, false otherwise.
+     */
+    bool hasAttr(uint32_t group, uint64_t attr) const;
+
+  protected:
+    int ioctl(int request, long p1) const;
+    int ioctl(int request, void *p1) const {
+        return ioctl(request, (long)p1);
+    }
+    int ioctl(int request) const {
+        return ioctl(request, 0L);
+    }
+
+  private:
+    int fd;
+};
+
+#endif // __CPU_KVM_DEVICE_HH__
diff --git a/src/cpu/kvm/vm.cc b/src/cpu/kvm/vm.cc
index 01670fab4..a12374aa5 100644
--- a/src/cpu/kvm/vm.cc
+++ b/src/cpu/kvm/vm.cc
@@ -1,6 +1,6 @@
 /*
  * Copyright 2014 Google, Inc.
- * Copyright (c) 2012 ARM Limited
+ * Copyright (c) 2012, 2015 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -486,6 +486,23 @@ KvmVM::setIRQLine(uint32_t irq, bool high)
 }
 
 int
+KvmVM::createDevice(uint32_t type, uint32_t flags)
+{
+#if defined(KVM_CREATE_DEVICE)
+    struct kvm_create_device dev = { type, 0, flags };
+
+    if (ioctl(KVM_CREATE_DEVICE, &dev) == -1) {
+        panic("KVM: Failed to create device (errno: %i)\n",
+              errno);
+    }
+
+    return dev.fd;
+#else
+    panic("Kernel headers don't support KVM_CREATE_DEVICE\n");
+#endif
+}
+
+int
 KvmVM::createVCPU(long vcpuID)
 {
     int fd;
diff --git a/src/cpu/kvm/vm.hh b/src/cpu/kvm/vm.hh
index 4710f2447..d21fc2660 100644
--- a/src/cpu/kvm/vm.hh
+++ b/src/cpu/kvm/vm.hh
@@ -1,6 +1,6 @@
 /*
  * Copyright 2014 Google, Inc.
- * Copyright (c) 2012 ARM Limited
+ * Copyright (c) 2012, 2015 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -386,6 +386,15 @@ class KvmVM : public SimObject
      */
     void freeMemSlot(const MemSlot slot);
 
+    /**
+     * Create an in-kernel device model.
+     *
+     * @param type Device type (KVM_DEV_TYPE_xxx)
+     * @param flags Creation flags (KVM_CREATE_DEVICE_xxx)
+     * @return Device file descriptor
+     */
+    int createDevice(uint32_t type, uint32_t flags = 0);
+
     /** Global KVM interface */
     Kvm kvm;