dev,arch-x86: Create an x86 QEMU fw cfg, and an E820 entry type.

The x86 version is basically just a specialization of the base IO port
version of the QEMU firmware configuration device, with the port
addresses set for x86.

The E820 entry type is x86 specific, and is a way to pass an E820 memory
map to firmware which doesn't have another way to figure out where
memory is. This would be for firmware like SeaBIOS which is itself
responsible for publishing an E820 map, but it needs somewhere to get
that information from in the first place. This mechanism is one it
supports natively.

This entry type reuses the E820Entry SimObjects which were defined a
long time ago for passing to a Linux FS workload. It doesn't use their
ability to write themselves out to guest memory, and just uses them as a
transport for their address, size and type properties.

Change-Id: Ifff214f5fc10bd7d0a2a0acddad4fc00dd65f67d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/55628
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>

src/dev/x86/SConscript

@@ -65,3 +65,6 @@ DebugFlag('PcSpeaker', tags='x86 isa')
 SimObject('I82094AA.py', sim_objects=['I82094AA'], tags='x86 isa')
 Source('i82094aa.cc', tags='x86 isa')
 DebugFlag('I82094AA', tags='x86 isa')
+
+SimObject('X86QemuFwCfg.py', sim_objects=['QemuFwCfgItemE820'], tags='x86 isa')
+Source('qemu_fw_cfg.cc', tags='x86 isa')

src/dev/x86/X86QemuFwCfg.py

@@ -0,0 +1,48 @@
+# Copyright 2022 Google, Inc.
+#
+# 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.
+
+from m5.params import *
+from m5.objects.E820 import X86E820Entry
+from m5.objects.QemuFwCfg import QemuFwCfgIo, QemuFwCfgItem
+
+def x86IOAddress(port):
+    IO_address_space_base = 0x8000000000000000
+    return IO_address_space_base + port;
+
+class X86QemuFwCfg(QemuFwCfgIo):
+    selector_addr = x86IOAddress(0x510)
+
+class QemuFwCfgItemE820(QemuFwCfgItem):
+    type = 'QemuFwCfgItemE820'
+    cxx_class = 'gem5::qemu::FwCfgItemFactory<gem5::qemu::FwCfgItemE820>'
+    cxx_template_params = ['class ItemType']
+    cxx_header = 'dev/x86/qemu_fw_cfg.hh'
+
+    # There is a fixed index for this file.
+    index = 0x8003
+    arch_specific = True
+    path = "etc/e820"
+
+    entries = VectorParam.X86E820Entry('entries for the e820 table')

src/dev/x86/qemu_fw_cfg.cc

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2022 Google, Inc.
+ *
+ * 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.
+ */
+
+#include "dev/x86/qemu_fw_cfg.hh"
+
+#include "arch/x86/bios/e820.hh"
+#include "base/compiler.hh"
+#include "base/logging.hh"
+#include "sim/byteswap.hh"
+
+namespace gem5
+{
+
+namespace qemu
+{
+
+FwCfgItemE820::FwCfgItemE820(const QemuFwCfgItemE820Params &p) :
+    FwCfgItemFixed(p.path, p.arch_specific, p.index)
+{
+    struct GEM5_PACKED Entry
+    {
+        uint64_t addr;
+        uint64_t size;
+        uint32_t type;
+    };
+
+    uint32_t count = p.entries.size();
+
+    panic_if(count >= 128, "Too many E820 entries (%d).", count);
+
+    size_t bytes = count * sizeof(Entry);
+    data.resize(bytes);
+
+    uint8_t *ptr = data.data();
+
+    // Write out the e820 entries.
+    for (auto *e: p.entries) {
+        Entry entry{htole(e->addr), htole(e->size), htole(e->type)};
+        std::memcpy(ptr, &entry, sizeof(entry));
+        ptr += sizeof(entry);
+    }
+};
+
+} // namespace qemu
+} // namespace gem5

src/dev/x86/qemu_fw_cfg.hh

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2022 Google, Inc.
+ *
+ * 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.
+ */
+
+#ifndef __DEV_X86_QEMU_FW_CFG_HH__
+#define __DEV_X86_QEMU_FW_CFG_HH__
+
+#include <vector>
+
+#include "dev/qemu/fw_cfg.hh"
+#include "params/QemuFwCfgItemE820.hh"
+
+namespace gem5
+{
+
+namespace qemu
+{
+
+// An item which holds the E820 table, precomputed for the firmware.
+class FwCfgItemE820 : public FwCfgItemFixed
+{
+  private:
+    std::vector<uint8_t> data;
+
+  public:
+    FwCfgItemE820(const QemuFwCfgItemE820Params &p);
+
+    const void *bytes() const override { return data.data(); }
+    uint64_t length() const override { return data.size(); }
+};
+
+} // namespace qemu
+} // namespace gem5
+
+#endif //__DEV_X86_QEMU_FW_CFG_HH__