dev: Add support for 9p proxying over VirtIO

This patch adds support for 9p filesystem proxying over VirtIO. It can
currently operate by connecting to a 9p server over a socket
(VirtIO9PSocket) or by starting the diod 9p server and connecting over
pipe (VirtIO9PDiod).


*WARNING*: Checkpoints are currently not supported for systems with 9p
 proxies!

4 files changed, 926 insertions, 0 deletions

diff --git a/src/dev/virtio/SConscript b/src/dev/virtio/SConscript
index 42dc480f0..796aa76f3 100644
--- a/src/dev/virtio/SConscript
+++ b/src/dev/virtio/SConscript
@@ -45,13 +45,17 @@ if env['TARGET_ISA'] == 'null':
 SimObject('VirtIO.py')
 SimObject('VirtIOConsole.py')
 SimObject('VirtIOBlock.py')
+SimObject('VirtIO9P.py')
 
 Source('base.cc')
 Source('pci.cc')
 Source('console.cc')
 Source('block.cc')
+Source('fs9p.cc')
 
 DebugFlag('VIO', 'VirtIO base functionality')
 DebugFlag('VIOPci', 'VirtIO PCI transport')
 DebugFlag('VIOConsole', 'VirtIO console device')
 DebugFlag('VIOBlock', 'VirtIO block device')
+DebugFlag('VIO9P', 'General 9p over VirtIO debugging')
+DebugFlag('VIO9PData', 'Dump data in VirtIO 9p connections')
diff --git a/src/dev/virtio/VirtIO9P.py b/src/dev/virtio/VirtIO9P.py
new file mode 100644
index 000000000..a13107db4
--- /dev/null
+++ b/src/dev/virtio/VirtIO9P.py
@@ -0,0 +1,70 @@
+# -*- mode:python -*-
+
+# Copyright (c) 2014 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
+
+from m5.params import *
+from m5.proxy import *
+from VirtIO import VirtIODeviceBase
+
+class VirtIO9PBase(VirtIODeviceBase):
+    type = 'VirtIO9PBase'
+    abstract = True
+    cxx_header = 'dev/virtio/fs9p.hh'
+
+    queueSize = Param.Unsigned(32, "Output queue size (pages)")
+    tag = Param.String("gem5", "Mount tag")
+
+
+class VirtIO9PProxy(VirtIO9PBase):
+    type = 'VirtIO9PProxy'
+    abstract = True
+    cxx_header = 'dev/virtio/fs9p.hh'
+
+class VirtIO9PDiod(VirtIO9PProxy):
+    type = 'VirtIO9PDiod'
+    cxx_header = 'dev/virtio/fs9p.hh'
+
+    diod = Param.String("/usr/sbin/diod", "Path to diod")
+    root = Param.String("/tmp", "Path to export through diod")
+
+class VirtIO9PSocket(VirtIO9PProxy):
+    type = 'VirtIO9PSocket'
+    cxx_header = 'dev/virtio/fs9p.hh'
+
+    server = Param.String("127.0.0.1", "9P server address or host name")
+    port = Param.String("564", "9P server port")
diff --git a/src/dev/virtio/fs9p.cc b/src/dev/virtio/fs9p.cc
new file mode 100644
index 000000000..b09ab15aa
--- /dev/null
+++ b/src/dev/virtio/fs9p.cc
@@ -0,0 +1,481 @@
+/*
+ * Copyright (c) 2014 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 <netinet/in.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <unistd.h>
+
+#include "debug/VIO9P.hh"
+#include "debug/VIO9PData.hh"
+#include "dev/virtio/fs9p.hh"
+#include "params/VirtIO9PBase.hh"
+#include "params/VirtIO9PDiod.hh"
+#include "params/VirtIO9PProxy.hh"
+#include "params/VirtIO9PSocket.hh"
+#include "sim/system.hh"
+
+struct P9MsgInfo {
+    P9MsgInfo(P9MsgType _type, std::string _name)
+        : type(_type), name(_name) {}
+
+    P9MsgType type;
+    std::string name;
+};
+
+typedef std::map<P9MsgType, P9MsgInfo> P9MsgInfoMap;
+
+#define P9MSG(type, name)                               \
+    { (type), P9MsgInfo((type), "T" # name ) },         \
+    { (type + 1), P9MsgInfo((type + 1), "R" # name ) }
+
+static const P9MsgInfoMap p9_msg_info {
+    P9MSG(6, LERROR),
+    P9MSG(8, STATFS),
+    P9MSG(12, LOPEN),
+    P9MSG(14, LCREATE),
+    P9MSG(16, SYMLINK),
+    P9MSG(18, MKNOD),
+    P9MSG(20, RENAME),
+    P9MSG(22, READLINK),
+    P9MSG(24, GETATTR),
+    P9MSG(26, SETATTR),
+    P9MSG(30, XATTRWALK),
+    P9MSG(32, XATTRCREATE),
+    P9MSG(40, READDIR),
+    P9MSG(50, FSYNC),
+    P9MSG(52, LOCK),
+    P9MSG(54, GETLOCK),
+    P9MSG(70, LINK),
+    P9MSG(72, MKDIR),
+    P9MSG(74, RENAMEAT),
+    P9MSG(76, UNLINKAT),
+    P9MSG(100, VERSION),
+    P9MSG(102, AUTH),
+    P9MSG(104, ATTACH),
+    P9MSG(106, ERROR),
+    P9MSG(108, FLUSH),
+    P9MSG(110, WALK),
+    P9MSG(112, OPEN),
+    P9MSG(114, CREATE),
+    P9MSG(116, READ),
+    P9MSG(118, WRITE),
+    P9MSG(120, CLUNK),
+    P9MSG(122, REMOVE),
+    P9MSG(124, STAT),
+    P9MSG(126, WSTAT),
+};
+
+#undef P9MSG
+
+VirtIO9PBase::VirtIO9PBase(Params *params)
+    : VirtIODeviceBase(params, ID_9P,
+                       sizeof(Config) + params->tag.size(),
+                       F_MOUNT_TAG),
+      queue(params->system->physProxy, params->queueSize, *this)
+{
+    config.reset((Config *)
+                 operator new(configSize));
+    config->len = htov_legacy(params->tag.size());
+    memcpy(config->tag, params->tag.c_str(), params->tag.size());
+
+    registerQueue(queue);
+}
+
+
+VirtIO9PBase::~VirtIO9PBase()
+{
+}
+
+void
+VirtIO9PBase::readConfig(PacketPtr pkt, Addr cfgOffset)
+{
+    readConfigBlob(pkt, cfgOffset, (uint8_t *)config.get());
+}
+
+void
+VirtIO9PBase::FSQueue::onNotifyDescriptor(VirtDescriptor *desc)
+{
+    DPRINTF(VIO9P, "Got input data descriptor (len: %i)\n", desc->size());
+    DPRINTF(VIO9P, "\tPending transactions: %i\n", parent.pendingTransactions.size());
+
+    P9MsgHeader header;
+    desc->chainRead(0, (uint8_t *)&header, sizeof(header));
+    header = p9toh(header);
+
+    uint8_t data[header.len - sizeof(header)];
+    desc->chainRead(sizeof(header), data, sizeof(data));
+
+    // Keep track of pending transactions
+    parent.pendingTransactions[header.tag] = desc;
+
+    DPRINTF(VIO9P, "recvTMsg\n");
+    parent.dumpMsg(header, data, sizeof(data));
+
+    // Notify device of message
+    parent.recvTMsg(header, data, sizeof(data));
+}
+
+void
+VirtIO9PBase::sendRMsg(const P9MsgHeader &header, const uint8_t *data, size_t size)
+{
+    DPRINTF(VIO9P, "Sending RMsg\n");
+    dumpMsg(header, data, size);
+    DPRINTF(VIO9P, "\tPending transactions: %i\n", pendingTransactions.size());
+    assert(header.len >= sizeof(header));
+
+    VirtDescriptor *main_desc(pendingTransactions[header.tag]);
+    pendingTransactions.erase(header.tag);
+
+    // Find the first output descriptor
+    VirtDescriptor *out_desc(main_desc);
+    while (out_desc && !out_desc->isOutgoing())
+        out_desc = out_desc->next();
+    if (!out_desc)
+        panic("sendRMsg: Framing error, no output descriptor.\n");
+
+    P9MsgHeader header_out(htop9(header));
+    header_out.len = htop9(sizeof(P9MsgHeader) + size);
+
+    out_desc->chainWrite(0, (uint8_t *)&header_out, sizeof(header_out));
+    out_desc->chainWrite(sizeof(header_out), data, size);
+
+    queue.produceDescriptor(main_desc, sizeof(P9MsgHeader) + size);
+    kick();
+}
+
+void
+VirtIO9PBase::dumpMsg(const P9MsgHeader &header, const uint8_t *data, size_t size)
+{
+#ifndef NDEBUG
+    if (!DTRACE(VIO9P))
+        return;
+
+    const P9MsgInfoMap::const_iterator it_msg(p9_msg_info.find(header.type));
+    if (it_msg != p9_msg_info.cend()) {
+        const P9MsgInfo &info(it_msg->second);
+        DPRINTF(VIO9P, "P9Msg[len = %i, type = %s (%i), tag = %i]\n",
+                header.len, info.name, header.type, header.tag);
+    } else {
+        DPRINTF(VIO9P, "P9Msg[len = %i, type = Unknown (%i), tag = %i]\n",
+                header.len, header.type, header.tag);
+    }
+    DDUMP(VIO9PData, data, size);
+#endif
+}
+
+
+VirtIO9PProxy::VirtIO9PProxy(Params *params)
+    : VirtIO9PBase(params)
+{
+}
+
+VirtIO9PProxy::~VirtIO9PProxy()
+{
+}
+
+
+void
+VirtIO9PProxy::VirtIO9PProxy::serialize(std::ostream &os)
+{
+    fatal("Can't checkpoint a system with a VirtIO 9p proxy!\n");
+}
+
+void
+VirtIO9PProxy::unserialize(Checkpoint *cp, const std::string &section)
+{
+    fatal("Can't checkpoint a system with a VirtIO 9p proxy!\n");
+}
+
+
+void
+VirtIO9PProxy::recvTMsg(const P9MsgHeader &header,
+                        const uint8_t *data, size_t size)
+{
+    assert(header.len == sizeof(header) + size);
+    // While technically not needed, we send the packet as one
+    // contiguous segment to make some packet dissectors happy.
+    uint8_t out[header.len];
+    P9MsgHeader header_out(htop9(header));
+    memcpy(out, (uint8_t *)&header_out, sizeof(header_out));
+    memcpy(out + sizeof(header_out), data, size);
+    writeAll(out, sizeof(header_out) + size);
+}
+
+void
+VirtIO9PProxy::serverDataReady()
+{
+    P9MsgHeader header;
+    readAll((uint8_t *)&header, sizeof(header));
+    header = p9toh(header);
+
+    const ssize_t payload_len(header.len - sizeof(header));
+    if (payload_len < 0)
+        panic("Payload length is negative!\n");
+    uint8_t data[payload_len];
+    readAll(data, payload_len);
+
+    sendRMsg(header, data, payload_len);
+}
+
+
+void
+VirtIO9PProxy::readAll(uint8_t *data, size_t len)
+{
+    while (len) {
+        ssize_t ret;
+        while ((ret = read(data, len)) == -EAGAIN)
+            ;
+        if (ret < 0)
+            panic("readAll: Read failed: %i\n", -ret);
+
+        len -= ret;
+        data += ret;
+    }
+}
+
+void
+VirtIO9PProxy::writeAll(const uint8_t *data, size_t len)
+{
+    while (len) {
+        ssize_t ret;
+        while ((ret = write(data, len)) == -EAGAIN)
+            ;
+        if (ret < 0)
+            panic("writeAll: write failed: %i\n", -ret);
+
+        len -= ret;
+        data += ret;
+    }
+}
+
+
+
+VirtIO9PDiod::VirtIO9PDiod(Params *params)
+    : VirtIO9PProxy(params),
+      fd_to_diod(-1), fd_from_diod(-1)
+{
+}
+
+VirtIO9PDiod::~VirtIO9PDiod()
+{
+}
+
+void
+VirtIO9PDiod::startup()
+{
+    startDiod();
+    dataEvent.reset(new DiodDataEvent(*this, fd_from_diod, POLLIN));
+    pollQueue.schedule(dataEvent.get());
+}
+
+void
+VirtIO9PDiod::startDiod()
+{
+    const Params *p(dynamic_cast<const Params *>(params()));
+    int pipe_rfd[2];
+    int pipe_wfd[2];
+    const int DIOD_RFD = 3;
+    const int DIOD_WFD = 4;
+
+    const char *diod(p->diod.c_str());
+
+    if (pipe(pipe_rfd) == -1 || pipe(pipe_wfd) == -1)
+        panic("Failed to create DIOD pipes: %i\n", errno);
+
+    fd_to_diod = pipe_rfd[1];
+    fd_from_diod = pipe_wfd[0];
+
+    diod_pid = fork();
+    if (diod_pid == -1) {
+        panic("Fork failed: %i\n", errno);
+    } else if (diod_pid == 0) {
+        close(STDIN_FILENO);
+
+        if (dup2(pipe_rfd[0], DIOD_RFD) == -1 ||
+            dup2(pipe_wfd[1], DIOD_WFD) == -1) {
+
+            panic("Failed to setup read/write pipes: %i\n",
+                  errno);
+        }
+
+        execlp(diod, diod,
+               "-f", // start in foreground
+               "-r", "3", // setup read FD
+               "-w", "4", // setup write FD
+               "-e", p->root.c_str(), // path to export
+               "-n", // disable security
+               "-S", // squash all users
+               (char *)NULL);
+        panic("Failed to execute diod: %i\n", errno);
+    } else {
+        close(pipe_rfd[0]);
+        close(pipe_wfd[1]);
+    }
+
+#undef DIOD_RFD
+#undef DIOD_WFD
+}
+
+ssize_t
+VirtIO9PDiod::read(uint8_t *data, size_t len)
+{
+    assert(fd_from_diod != -1);
+    const int ret(::read(fd_from_diod, (void *)data, len));
+    return ret < 0 ? -errno : ret;
+}
+
+ssize_t
+VirtIO9PDiod::write(const uint8_t *data, size_t len)
+{
+    assert(fd_to_diod != -1);
+    const int ret(::write(fd_to_diod, (const void *)data, len));
+    return ret < 0 ? -errno : ret;
+}
+
+void
+VirtIO9PDiod::DiodDataEvent::process(int revent)
+{
+    parent.serverDataReady();
+}
+
+VirtIO9PDiod *
+VirtIO9PDiodParams::create()
+{
+    return new VirtIO9PDiod(this);
+}
+
+
+
+
+VirtIO9PSocket::VirtIO9PSocket(Params *params)
+    : VirtIO9PProxy(params), fdSocket(-1)
+{
+}
+
+VirtIO9PSocket::~VirtIO9PSocket()
+{
+}
+
+void
+VirtIO9PSocket::startup()
+{
+    connectSocket();
+    dataEvent.reset(new SocketDataEvent(*this, fdSocket, POLLIN));
+    pollQueue.schedule(dataEvent.get());
+}
+
+void
+VirtIO9PSocket::connectSocket()
+{
+    const Params &p(dynamic_cast<const Params &>(*params()));
+
+    int ret;
+    struct addrinfo hints, *result;
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = AF_UNSPEC;
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_flags = 0;
+    hints.ai_protocol = 0;
+
+    if ((ret = getaddrinfo(p.server.c_str(), p.port.c_str(),
+                           &hints, &result)) != 0)
+        panic("getaddrinfo: %s\n", gai_strerror(ret));
+
+    DPRINTF(VIO9P, "Connecting to 9p server '%s'.\n", p.server);
+    for (struct addrinfo *rp = result; rp; rp = rp->ai_next) {
+        fdSocket = socket(rp->ai_family, rp->ai_socktype,
+                     rp->ai_protocol);
+        if (fdSocket == -1) {
+            continue;
+        } else if (connect(fdSocket, rp->ai_addr, rp->ai_addrlen) != -1) {
+            break;
+        } else {
+            close(fdSocket);
+            fdSocket = -1;
+        }
+    }
+
+    freeaddrinfo(result);
+
+    if (fdSocket == -1)
+        panic("Failed to connect to 9p server (%s:%s)", p.server, p.port);
+}
+
+void
+VirtIO9PSocket::socketDisconnect()
+{
+    panic("9P Socket disconnected!\n");
+}
+
+ssize_t
+VirtIO9PSocket::read(uint8_t *data, size_t len)
+{
+    assert(fdSocket != -1);
+    int ret;
+
+    ret = ::recv(fdSocket, (void *)data, len, 0);
+    if (ret == 0)
+        socketDisconnect();
+
+    return ret < 0 ? -errno : ret;
+}
+
+ssize_t
+VirtIO9PSocket::write(const uint8_t *data, size_t len)
+{
+    assert(fdSocket != -1);
+    int ret(::send(fdSocket, (const void *)data, len, 0));
+    return ret < 0 ? -errno : ret;
+}
+
+void
+VirtIO9PSocket::SocketDataEvent::process(int revent)
+{
+    parent.serverDataReady();
+}
+
+
+VirtIO9PSocket *
+VirtIO9PSocketParams::create()
+{
+    return new VirtIO9PSocket(this);
+}
diff --git a/src/dev/virtio/fs9p.hh b/src/dev/virtio/fs9p.hh
new file mode 100644
index 000000000..2cbdbc9eb
--- /dev/null
+++ b/src/dev/virtio/fs9p.hh
@@ -0,0 +1,371 @@
+/*
+ * Copyright (c) 2014 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 __DEV_VIRTIO_FS9P_HH__
+#define __DEV_VIRTIO_FS9P_HH__
+
+#include <map>
+#include <memory>
+#include <string>
+
+#include "base/pollevent.hh"
+#include "dev/virtio/base.hh"
+
+struct VirtIO9PBaseParams;
+
+typedef uint8_t P9MsgType;
+typedef uint16_t P9Tag;
+
+struct P9MsgHeader {
+    /** Length including header */
+    uint32_t len;
+    /** Message type */
+    P9MsgType type;
+    /** Message tag */
+    P9Tag tag;
+} M5_ATTR_PACKED;
+
+/** Convert p9 byte order (LE) to host byte order */
+template <typename T> inline T
+p9toh(T v) { return letoh(v); }
+
+/** Convert host byte order to p9 byte order (LE) */
+template <typename T> inline T
+htop9(T v) { return htole(v); }
+
+template <> inline P9MsgHeader
+p9toh(P9MsgHeader v)
+{
+    v.len = p9toh(v.len);
+    v.type = p9toh(v.type);
+    v.tag = p9toh(v.tag);
+    return v;
+}
+
+template <> inline P9MsgHeader
+htop9(P9MsgHeader v)
+{
+    v.len = htop9(v.len);
+    v.type = htop9(v.type);
+    v.tag = htop9(v.tag);
+    return v;
+}
+
+/**
+ * This class implements a VirtIO transport layer for the 9p network
+ * file system.
+ *
+ * The 9p VirtIO transport uses the following queues:
+ *  -# 9p requests and replies
+ *
+ * Each 9p request and response is sent in its own descriptor
+ * chain. The guest initiates a transaction by packing a T message
+ * (see the 9p spec) into the first part of a descriptor chain. After
+ * the T message, the guest reserves space for the reply (R message)
+ * by including one or more writable descriptors. The server replies
+ * by writing an R message into the writable descriptors and putting
+ * the chain in the used ring (VirtQueue::produceDescriptor()).
+ *
+ * @see https://github.com/rustyrussell/virtio-spec
+ * @see https://github.com/ericvh/9p-rfc
+ * @see https://code.google.com/p/diod/wiki/protocol
+ */
+class VirtIO9PBase : public VirtIODeviceBase
+{
+  public:
+    typedef VirtIO9PBaseParams Params;
+    VirtIO9PBase(Params *params);
+    virtual ~VirtIO9PBase();
+
+    void readConfig(PacketPtr pkt, Addr cfgOffset);
+
+  protected:
+    /**
+     * VirtIO 9p configuration structure
+     *
+     * @note The fields in this structure depend on the features
+     * exposed to the guest.
+     */
+    struct Config {
+        uint16_t len;
+        char tag[];
+    } M5_ATTR_PACKED;
+
+    /** Currently active configuration (host byte order) */
+    std::unique_ptr<Config> config;
+
+    /** VirtIO device ID */
+    static const DeviceId ID_9P = 0x09;
+
+    /** @{
+     * @name Feature bits
+     */
+    /** Device provides a name of the resource in its configuration */
+    static const FeatureBits F_MOUNT_TAG = 0x01;
+    /** @} */
+
+  protected:
+    /**
+     * Virtqueue for 9p requests
+     */
+    class FSQueue : public VirtQueue
+    {
+      public:
+        FSQueue(PortProxy &proxy, uint16_t size, VirtIO9PBase &_parent)
+            : VirtQueue(proxy, size), parent(_parent) {}
+        virtual ~FSQueue() {}
+
+        void onNotifyDescriptor(VirtDescriptor *desc);
+
+        std::string name() const { return parent.name() + ".queue"; }
+
+      protected:
+        VirtIO9PBase &parent;
+    };
+
+    FSQueue queue;
+
+  protected:
+    /**
+     * Handle incoming 9p RPC message.
+     *
+     * @param header 9p message header.
+     * @param data Pointer to data in message.
+     * @param size Size of data (excluding header)
+     */
+    virtual void recvTMsg(const P9MsgHeader &header, const uint8_t *data, size_t size) = 0;
+    /**
+     * Send a 9p RPC message reply.
+     *
+     * @param header 9p message header.
+     * @param data Pointer to data in message.
+     * @param size Size of data (excluding header)
+     */
+    void sendRMsg(const P9MsgHeader &header, const uint8_t *data, size_t size);
+
+    /**
+     * Dump a 9p RPC message on the debug output
+     *
+     * @param header 9p message header.
+     * @param data Pointer to data in message.
+     * @param size Size of data (excluding header)
+     */
+    void dumpMsg(const P9MsgHeader &header, const uint8_t *data, size_t size);
+
+  private:
+    /**
+     * Map between 9p transaction tags and descriptors where they
+     * appeared.
+     *
+     * When handling asynchronous requests, we need to ensure that
+     * replies are posted in the same descriptor as queries. The 9p
+     * RPC protocol uses the tag field in the header to match requests
+     * and replies, which we use here to find the relevant descriptor.
+     */
+    std::map<P9Tag, VirtDescriptor *> pendingTransactions;
+};
+
+struct VirtIO9PProxyParams;
+
+/**
+ * VirtIO 9p proxy base class.
+ *
+ * This base class provides basic functionality shared by different 9p
+ * proxy implementations.
+ */
+class VirtIO9PProxy : public VirtIO9PBase
+{
+  public:
+    typedef VirtIO9PProxyParams Params;
+    VirtIO9PProxy(Params *params);
+    virtual ~VirtIO9PProxy();
+
+    void serialize(std::ostream &os);
+    void unserialize(Checkpoint *cp, const std::string &section);
+
+  protected:
+    void recvTMsg(const P9MsgHeader &header, const uint8_t *data, size_t size);
+
+    /** Notification of pending data from server */
+    void serverDataReady();
+
+    /**
+     * Read data from the server behind the proxy.
+     *
+     * @note This method may return read fewer than len bytes.
+     *
+     * @param data Memory location to store results in.
+     * @param len Maximum length to read.
+     * @return Number of bytes read, -errno on failure.
+     */
+    virtual ssize_t read(uint8_t *data, size_t len) = 0;
+    /**
+     * Write data to the server behind the proxy.
+     *
+     * @note This method may return write fewer than len bytes.
+     *
+     * @param data Pointer to data to write.
+     * @param len Maximum length to write.
+     * @return Number of bytes written, -errno on failure.
+     */
+    virtual ssize_t write(const uint8_t *data, size_t len) = 0;
+
+    /**
+     * Convenience function that reads exactly len bytes.
+     *
+     * This method calls read until exactly len number of bytes has
+     * been read. A read() call is retried if the underlying syscall
+     * was interrupted.
+     *
+     * @param data Memory location to store results in.
+     * @param len Number of bytes to read.
+     */
+    void readAll(uint8_t *data, size_t len);
+    /**
+     * Convenience function that writes exactly len bytes.
+     *
+     * This method calls write until exactly len number of bytes has
+     * been written. A write() call is retried if the underlying
+     * syscall was interrupted.
+     *
+     * @param data Data to write.
+     * @param len Number of bytes to write.
+     */
+    void writeAll(const uint8_t *data, size_t len);
+};
+
+struct VirtIO9PDiodParams;
+
+/**
+ * VirtIO 9p proxy that communicates with the diod 9p server using
+ * pipes.
+ */
+class VirtIO9PDiod : public VirtIO9PProxy
+{
+  public:
+    typedef VirtIO9PDiodParams Params;
+    VirtIO9PDiod(Params *params);
+    virtual ~VirtIO9PDiod();
+
+    void startup();
+
+  protected:
+    /**
+     * Start diod and setup the communication pipes.
+     */
+    void startDiod();
+
+    ssize_t read(uint8_t *data, size_t len);
+    ssize_t write(const uint8_t *data, size_t len);
+
+  private:
+    class DiodDataEvent : public PollEvent
+    {
+      public:
+        DiodDataEvent(VirtIO9PDiod &_parent, int fd, int event)
+            : PollEvent(fd, event), parent(_parent) {}
+
+        virtual ~DiodDataEvent() {};
+
+        void process(int revent);
+
+      private:
+        VirtIO9PDiod &parent;
+    };
+
+    /** fd for data pipe going to diod (write end) */
+    int fd_to_diod;
+    /** fd for data pipe coming from diod (read end) */
+    int fd_from_diod;
+
+    std::unique_ptr<DiodDataEvent> dataEvent;
+
+    /** PID of diod process */
+    int diod_pid;
+};
+
+struct VirtIO9PSocketParams;
+
+/**
+ * VirtIO 9p proxy that communicates with a 9p server over tcp
+ * sockets.
+ */
+class VirtIO9PSocket : public VirtIO9PProxy
+{
+  public:
+    typedef VirtIO9PSocketParams Params;
+    VirtIO9PSocket(Params *params);
+    virtual ~VirtIO9PSocket();
+
+    void startup();
+
+  protected:
+    /**
+     * Try to resolve the server name and connect to the 9p server.
+     */
+    void connectSocket();
+
+    /** 9p server disconnect notification */
+    void socketDisconnect();
+
+    ssize_t read(uint8_t *data, size_t len);
+    ssize_t write(const uint8_t *data, size_t len);
+
+  private:
+    class SocketDataEvent : public PollEvent
+    {
+      public:
+        SocketDataEvent(VirtIO9PSocket &_parent, int fd, int event)
+            : PollEvent(fd, event), parent(_parent) {}
+
+        virtual ~SocketDataEvent() {};
+
+        void process(int revent);
+
+      private:
+        VirtIO9PSocket &parent;
+    };
+
+    /** Socket connected to the 9p server */
+    int fdSocket;
+
+    std::unique_ptr<SocketDataEvent> dataEvent;
+};
+
+#endif // __DEV_VIRTIO_FS9P_HH__