kvm: Initial x86 support

This changeset adds support for KVM on x86. Full support is split
across a number of commits since some features are relatively
complex. This changeset includes support for:

 * Integer state synchronization (including segment regs)
 * CPUID (gem5's CPUID values are inserted into KVM)
 * x86 legacy IO (remapped and handled by gem5's memory system)
 * Memory mapped IO
 * PCI
 * MSRs
 * State dumping

Most of the functionality is fairly straight forward. There are some
quirks to support PCI enumerations since this is done in the TLB(!) in
the simulated CPUs. We currently replicate some of that code.

Unlike the ARM implementation, the x86 implementation of the virtual
CPU does not use the cycles hardware counter. KVM on x86 simulates the
time stamp counter (TSC) in the kernel. If we just measure host cycles
using perfevent, we might end up measuring a slightly different number
of cycles. If we don't get the cycle accounting right, we might end up
rewinding the TSC, with all kinds of chaos as a result.

An additional feature of the KVM CPU on x86 is extended state
dumping. This enables Python scripts controlling the simulator to
request dumping of a subset of the processor state. The following
methods are currenlty supported:

 * dumpFpuRegs
 * dumpIntRegs
 * dumpSpecRegs
 * dumpDebugRegs
 * dumpXCRs
 * dumpXSave
 * dumpVCpuEvents
 * dumpMSRs

Known limitations:
  * M5 ops are currently not supported.
  * FPU synchronization is not supported (only affects CPU switching).

Both of the limitations will be addressed in separate commits.

1 files changed, 45 insertions, 0 deletions

diff --git a/src/cpu/kvm/X86KvmCPU.py b/src/cpu/kvm/X86KvmCPU.py
new file mode 100644
index 000000000..0b12da676
--- /dev/null
+++ b/src/cpu/kvm/X86KvmCPU.py
@@ -0,0 +1,45 @@
+# Copyright (c) 2013 Andreas Sandberg
+# All rights reserved.
+#
+# 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
+
+from m5.params import *
+from BaseKvmCPU import BaseKvmCPU
+
+class X86KvmCPU(BaseKvmCPU):
+    type = 'X86KvmCPU'
+    cxx_header = "cpu/kvm/x86_cpu.hh"
+
+    @classmethod
+    def export_methods(cls, code):
+        code('''
+      void dumpFpuRegs();
+      void dumpIntRegs();
+      void dumpSpecRegs();
+      void dumpXCRs();
+      void dumpXSave();
+      void dumpVCpuEvents();
+''')