fs9p.hh revision 11168 
1/*
2 * Copyright (c) 2014 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder.  You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions are
16 * met: redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer;
18 * redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution;
21 * neither the name of the copyright holders nor the names of its
22 * contributors may be used to endorse or promote products derived from
23 * this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 *
37 * Authors: Andreas Sandberg
38 */
39
40#ifndef __DEV_VIRTIO_FS9P_HH__
41#define __DEV_VIRTIO_FS9P_HH__
42
43#include <map>
44#include <memory>
45#include <string>
46
47#include "base/pollevent.hh"
48#include "dev/virtio/base.hh"
49
50struct VirtIO9PBaseParams;
51
52typedef uint8_t P9MsgType;
53typedef uint16_t P9Tag;
54
55struct P9MsgHeader {
56    /** Length including header */
57    uint32_t len;
58    /** Message type */
59    P9MsgType type;
60    /** Message tag */
61    P9Tag tag;
62} M5_ATTR_PACKED;
63
64/** Convert p9 byte order (LE) to host byte order */
65template <typename T> inline T
66p9toh(T v) { return letoh(v); }
67
68/** Convert host byte order to p9 byte order (LE) */
69template <typename T> inline T
70htop9(T v) { return htole(v); }
71
72template <> inline P9MsgHeader
73p9toh(P9MsgHeader v)
74{
75    v.len = p9toh(v.len);
76    v.type = p9toh(v.type);
77    v.tag = p9toh(v.tag);
78    return v;
79}
80
81template <> inline P9MsgHeader
82htop9(P9MsgHeader v)
83{
84    v.len = htop9(v.len);
85    v.type = htop9(v.type);
86    v.tag = htop9(v.tag);
87    return v;
88}
89
90/**
91 * This class implements a VirtIO transport layer for the 9p network
92 * file system.
93 *
94 * The 9p VirtIO transport uses the following queues:
95 *  -# 9p requests and replies
96 *
97 * Each 9p request and response is sent in its own descriptor
98 * chain. The guest initiates a transaction by packing a T message
99 * (see the 9p spec) into the first part of a descriptor chain. After
100 * the T message, the guest reserves space for the reply (R message)
101 * by including one or more writable descriptors. The server replies
102 * by writing an R message into the writable descriptors and putting
103 * the chain in the used ring (VirtQueue::produceDescriptor()).
104 *
105 * @see https://github.com/rustyrussell/virtio-spec
106 * @see https://github.com/ericvh/9p-rfc
107 * @see https://code.google.com/p/diod/wiki/protocol
108 */
109class VirtIO9PBase : public VirtIODeviceBase
110{
111  public:
112    typedef VirtIO9PBaseParams Params;
113    VirtIO9PBase(Params *params);
114    virtual ~VirtIO9PBase();
115
116    void readConfig(PacketPtr pkt, Addr cfgOffset);
117
118  protected:
119    /**
120     * VirtIO 9p configuration structure
121     *
122     * @note The fields in this structure depend on the features
123     * exposed to the guest.
124     */
125    struct Config {
126        uint16_t len;
127        char tag[];
128    } M5_ATTR_PACKED;
129
130    /** Currently active configuration (host byte order) */
131    std::unique_ptr<Config> config;
132
133    /** VirtIO device ID */
134    static const DeviceId ID_9P = 0x09;
135
136    /** @{
137     * @name Feature bits
138     */
139    /** Device provides a name of the resource in its configuration */
140    static const FeatureBits F_MOUNT_TAG = 0x01;
141    /** @} */
142
143  protected:
144    /**
145     * Virtqueue for 9p requests
146     */
147    class FSQueue : public VirtQueue
148    {
149      public:
150        FSQueue(PortProxy &proxy, uint16_t size, VirtIO9PBase &_parent)
151            : VirtQueue(proxy, size), parent(_parent) {}
152        virtual ~FSQueue() {}
153
154        void onNotifyDescriptor(VirtDescriptor *desc);
155
156        std::string name() const { return parent.name() + ".queue"; }
157
158      protected:
159        VirtIO9PBase &parent;
160    };
161
162    FSQueue queue;
163
164  protected:
165    /**
166     * Handle incoming 9p RPC message.
167     *
168     * @param header 9p message header.
169     * @param data Pointer to data in message.
170     * @param size Size of data (excluding header)
171     */
172    virtual void recvTMsg(const P9MsgHeader &header, const uint8_t *data, size_t size) = 0;
173    /**
174     * Send a 9p RPC message reply.
175     *
176     * @param header 9p message header.
177     * @param data Pointer to data in message.
178     * @param size Size of data (excluding header)
179     */
180    void sendRMsg(const P9MsgHeader &header, const uint8_t *data, size_t size);
181
182    /**
183     * Dump a 9p RPC message on the debug output
184     *
185     * @param header 9p message header.
186     * @param data Pointer to data in message.
187     * @param size Size of data (excluding header)
188     */
189    void dumpMsg(const P9MsgHeader &header, const uint8_t *data, size_t size);
190
191  private:
192    /**
193     * Map between 9p transaction tags and descriptors where they
194     * appeared.
195     *
196     * When handling asynchronous requests, we need to ensure that
197     * replies are posted in the same descriptor as queries. The 9p
198     * RPC protocol uses the tag field in the header to match requests
199     * and replies, which we use here to find the relevant descriptor.
200     */
201    std::map<P9Tag, VirtDescriptor *> pendingTransactions;
202};
203
204struct VirtIO9PProxyParams;
205
206/**
207 * VirtIO 9p proxy base class.
208 *
209 * This base class provides basic functionality shared by different 9p
210 * proxy implementations.
211 */
212class VirtIO9PProxy : public VirtIO9PBase
213{
214  public:
215    typedef VirtIO9PProxyParams Params;
216    VirtIO9PProxy(Params *params);
217    virtual ~VirtIO9PProxy();
218
219    void serialize(CheckpointOut &cp) const override;
220    void unserialize(CheckpointIn &cp) override;
221
222  protected:
223    void recvTMsg(const P9MsgHeader &header, const uint8_t *data, size_t size);
224
225    /** Notification of pending data from server */
226    void serverDataReady();
227
228    /**
229     * Read data from the server behind the proxy.
230     *
231     * @note This method may return read fewer than len bytes.
232     *
233     * @param data Memory location to store results in.
234     * @param len Maximum length to read.
235     * @return Number of bytes read, -errno on failure.
236     */
237    virtual ssize_t read(uint8_t *data, size_t len) = 0;
238    /**
239     * Write data to the server behind the proxy.
240     *
241     * @note This method may return write fewer than len bytes.
242     *
243     * @param data Pointer to data to write.
244     * @param len Maximum length to write.
245     * @return Number of bytes written, -errno on failure.
246     */
247    virtual ssize_t write(const uint8_t *data, size_t len) = 0;
248
249    /**
250     * Convenience function that reads exactly len bytes.
251     *
252     * This method calls read until exactly len number of bytes has
253     * been read. A read() call is retried if the underlying syscall
254     * was interrupted.
255     *
256     * @param data Memory location to store results in.
257     * @param len Number of bytes to read.
258     */
259    void readAll(uint8_t *data, size_t len);
260    /**
261     * Convenience function that writes exactly len bytes.
262     *
263     * This method calls write until exactly len number of bytes has
264     * been written. A write() call is retried if the underlying
265     * syscall was interrupted.
266     *
267     * @param data Data to write.
268     * @param len Number of bytes to write.
269     */
270    void writeAll(const uint8_t *data, size_t len);
271};
272
273struct VirtIO9PDiodParams;
274
275/**
276 * VirtIO 9p proxy that communicates with the diod 9p server using
277 * pipes.
278 */
279class VirtIO9PDiod : public VirtIO9PProxy
280{
281  public:
282    typedef VirtIO9PDiodParams Params;
283    VirtIO9PDiod(Params *params);
284    virtual ~VirtIO9PDiod();
285
286    void startup();
287
288  protected:
289    /**
290     * Start diod and setup the communication pipes.
291     */
292    void startDiod();
293
294    ssize_t read(uint8_t *data, size_t len);
295    ssize_t write(const uint8_t *data, size_t len);
296
297  private:
298    class DiodDataEvent : public PollEvent
299    {
300      public:
301        DiodDataEvent(VirtIO9PDiod &_parent, int fd, int event)
302            : PollEvent(fd, event), parent(_parent) {}
303
304        virtual ~DiodDataEvent() {};
305
306        void process(int revent);
307
308      private:
309        VirtIO9PDiod &parent;
310    };
311
312    /** fd for data pipe going to diod (write end) */
313    int fd_to_diod;
314    /** fd for data pipe coming from diod (read end) */
315    int fd_from_diod;
316
317    std::unique_ptr<DiodDataEvent> dataEvent;
318
319    /** PID of diod process */
320    int diod_pid;
321};
322
323struct VirtIO9PSocketParams;
324
325/**
326 * VirtIO 9p proxy that communicates with a 9p server over tcp
327 * sockets.
328 */
329class VirtIO9PSocket : public VirtIO9PProxy
330{
331  public:
332    typedef VirtIO9PSocketParams Params;
333    VirtIO9PSocket(Params *params);
334    virtual ~VirtIO9PSocket();
335
336    void startup();
337
338  protected:
339    /**
340     * Try to resolve the server name and connect to the 9p server.
341     */
342    void connectSocket();
343
344    /** 9p server disconnect notification */
345    void socketDisconnect();
346
347    ssize_t read(uint8_t *data, size_t len);
348    ssize_t write(const uint8_t *data, size_t len);
349
350  private:
351    class SocketDataEvent : public PollEvent
352    {
353      public:
354        SocketDataEvent(VirtIO9PSocket &_parent, int fd, int event)
355            : PollEvent(fd, event), parent(_parent) {}
356
357        virtual ~SocketDataEvent() {};
358
359        void process(int revent);
360
361      private:
362        VirtIO9PSocket &parent;
363    };
364
365    /** Socket connected to the 9p server */
366    int fdSocket;
367
368    std::unique_ptr<SocketDataEvent> dataEvent;
369};
370
371#endif // __DEV_VIRTIO_FS9P_HH__
372