kvm, arm: Add support for aarch64

This changeset adds support for aarch64 in kvm. The CPU module
supports both checkpointing and online CPU model switching as long as
no devices are simulated by the host kernel. It currently has the
following limitations:

   * The system register based generic timer can only be simulated by
     the host kernel. Workaround: Use a memory mapped timer instead to
     simulate the timer in gem5.

   * Simulating devices (e.g., the generic timer) in the host kernel
     requires that the host kernel also simulates the GIC.

   * ID registers in the host and in gem5 must match for switching
     between simulated CPUs and KVM. This is particularly important
     for ID registers describing memory system capabilities (e.g.,
     ASID size, physical address size).

   * Switching between a virtualized CPU and a simulated CPU is
     currently not supported if in-kernel device emulation is
     used. This could be worked around by adding support for switching
     to the gem5 (e.g., the KvmGic) side of the device models. A
     simpler workaround is to avoid in-kernel device models
     altogether.

1 files changed, 140 insertions, 0 deletions

diff --git a/src/arch/arm/kvm/armv8_cpu.hh b/src/arch/arm/kvm/armv8_cpu.hh
new file mode 100644
index 000000000..97127b471
--- /dev/null
+++ b/src/arch/arm/kvm/armv8_cpu.hh
@@ -0,0 +1,140 @@
+/*
+ * 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 __ARCH_ARM_KVM_ARMV8_CPU_HH__
+#define __ARCH_ARM_KVM_ARMV8_CPU_HH__
+
+#include <vector>
+
+#include "arch/arm/intregs.hh"
+#include "arch/arm/kvm/base_cpu.hh"
+#include "arch/arm/miscregs.hh"
+
+struct ArmV8KvmCPUParams;
+
+/**
+ * This is an implementation of a KVM-based ARMv8-compatible CPU.
+ *
+ * Known limitations:
+ * <ul>
+ *
+ *   <li>The system-register-based generic timer can only be simulated
+ *       by the host kernel. Workaround: Use a memory mapped timer
+ *       instead to simulate the timer in gem5.
+ *
+ *   <li>Simulating devices (e.g., the generic timer) in the host
+ *       kernel requires that the host kernel also simulates the
+ *       GIC.
+ *
+ *   <li>ID registers in the host and in gem5 must match for switching
+ *       between simulated CPUs and KVM. This is particularly
+ *       important for ID registers describing memory system
+ *       capabilities (e.g., ASID size, physical address size).
+ *
+ *   <li>Switching between a virtualized CPU and a simulated CPU is
+ *       currently not supported if in-kernel device emulation is
+ *       used. This could be worked around by adding support for
+ *       switching to the gem5 (e.g., the KvmGic) side of the device
+ *       models. A simpler workaround is to avoid in-kernel device
+ *       models altogether.
+ *
+ * </ul>
+ *
+ */
+class ArmV8KvmCPU : public BaseArmKvmCPU
+{
+  public:
+    ArmV8KvmCPU(ArmV8KvmCPUParams *params);
+    virtual ~ArmV8KvmCPU();
+
+    void dump() M5_ATTR_OVERRIDE;
+
+  protected:
+    void updateKvmState() M5_ATTR_OVERRIDE;
+    void updateThreadContext() M5_ATTR_OVERRIDE;
+
+  protected:
+    /** Mapping between integer registers in gem5 and KVM */
+    struct IntRegInfo {
+        IntRegInfo(uint64_t _kvm, IntRegIndex _idx, const char *_name)
+            : kvm(_kvm), idx(_idx), name(_name) {}
+
+        /** Register index in KVM */
+        uint64_t kvm;
+        /** Register index in gem5 */
+        IntRegIndex idx;
+        /** Name to use in debug dumps */
+        const char *name;
+    };
+
+    /** Mapping between misc registers in gem5 and registers in KVM */
+    struct MiscRegInfo {
+        MiscRegInfo(uint64_t _kvm, MiscRegIndex _idx, const char *_name)
+            : kvm(_kvm), idx(_idx), name(_name) {}
+
+        /** Register index in KVM */
+        uint64_t kvm;
+        /** Register index in gem5 */
+        MiscRegIndex idx;
+        /** Name to use in debug dumps */
+        const char *name;
+    };
+
+    /**
+     * Get a map between system registers in kvm and gem5 registers
+     *
+     * This method returns a mapping between system registers in kvm
+     * and misc regs in gem5. The actual mapping is only created the
+     * first time the method is called and stored in a cache
+     * (ArmV8KvmCPU::sysRegMap).
+     *
+     * @return Vector of kvm<->misc reg mappings.
+     */
+    const std::vector<ArmV8KvmCPU::MiscRegInfo> &getSysRegMap() const;
+
+    /** Mapping between gem5 integer registers and integer registers in kvm */
+    static const std::vector<ArmV8KvmCPU::IntRegInfo> intRegMap;
+    /** Mapping between gem5 misc registers registers and registers in kvm */
+    static const std::vector<ArmV8KvmCPU::MiscRegInfo> miscRegMap;
+
+    /** Cached mapping between system registers in kvm and misc regs in gem5 */
+    mutable std::vector<ArmV8KvmCPU::MiscRegInfo> sysRegMap;
+};
+
+#endif // __ARCH_ARM_KVM_ARMV8_CPU_HH__