xref: /openbmc/qemu/net/vmnet-common.m (revision ec8c2936) 
1/*
2 * vmnet-common.m - network client wrapper for Apple vmnet.framework
3 *
4 * Copyright(c) 2022 Vladislav Yaroshchuk <vladislav.yaroshchuk@jetbrains.com>
5 * Copyright(c) 2021 Phillip Tennen <phillip@axleos.com>
6 *
7 * This work is licensed under the terms of the GNU GPL, version 2 or later.
8 * See the COPYING file in the top-level directory.
9 *
10 */
11
12#include "qemu/osdep.h"
13#include "qemu/main-loop.h"
14#include "qemu/log.h"
15#include "qapi/qapi-types-net.h"
16#include "vmnet_int.h"
17#include "clients.h"
18#include "qemu/error-report.h"
19#include "qapi/error.h"
20
21#include <vmnet/vmnet.h>
22#include <dispatch/dispatch.h>
23
24
25static void vmnet_send_completed(NetClientState *nc, ssize_t len);
26
27
28const char *vmnet_status_map_str(vmnet_return_t status)
29{
30    switch (status) {
31    case VMNET_SUCCESS:
32        return "success";
33    case VMNET_FAILURE:
34        return "general failure (possibly not enough privileges)";
35    case VMNET_MEM_FAILURE:
36        return "memory allocation failure";
37    case VMNET_INVALID_ARGUMENT:
38        return "invalid argument specified";
39    case VMNET_SETUP_INCOMPLETE:
40        return "interface setup is not complete";
41    case VMNET_INVALID_ACCESS:
42        return "invalid access, permission denied";
43    case VMNET_PACKET_TOO_BIG:
44        return "packet size is larger than MTU";
45    case VMNET_BUFFER_EXHAUSTED:
46        return "buffers exhausted in kernel";
47    case VMNET_TOO_MANY_PACKETS:
48        return "packet count exceeds limit";
49#if defined(MAC_OS_VERSION_11_0) && \
50    MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_VERSION_11_0
51    case VMNET_SHARING_SERVICE_BUSY:
52        return "conflict, sharing service is in use";
53#endif
54    default:
55        return "unknown vmnet error";
56    }
57}
58
59
60/**
61 * Write packets from QEMU to vmnet interface.
62 *
63 * vmnet.framework supports iov, but writing more than
64 * one iov into vmnet interface fails with
65 * 'VMNET_INVALID_ARGUMENT'. Collecting provided iovs into
66 * one and passing it to vmnet works fine. That's the
67 * reason why receive_iov() left unimplemented. But it still
68 * works with good performance having .receive() only.
69 */
70ssize_t vmnet_receive_common(NetClientState *nc,
71                             const uint8_t *buf,
72                             size_t size)
73{
74    VmnetState *s = DO_UPCAST(VmnetState, nc, nc);
75    struct vmpktdesc packet;
76    struct iovec iov;
77    int pkt_cnt;
78    vmnet_return_t if_status;
79
80    if (size > s->max_packet_size) {
81        warn_report("vmnet: packet is too big, %zu > %" PRIu64,
82            packet.vm_pkt_size,
83            s->max_packet_size);
84        return -1;
85    }
86
87    iov.iov_base = (char *) buf;
88    iov.iov_len = size;
89
90    packet.vm_pkt_iovcnt = 1;
91    packet.vm_flags = 0;
92    packet.vm_pkt_size = size;
93    packet.vm_pkt_iov = &iov;
94    pkt_cnt = 1;
95
96    if_status = vmnet_write(s->vmnet_if, &packet, &pkt_cnt);
97    if (if_status != VMNET_SUCCESS) {
98        error_report("vmnet: write error: %s\n",
99                     vmnet_status_map_str(if_status));
100        return -1;
101    }
102
103    if (pkt_cnt) {
104        return size;
105    }
106    return 0;
107}
108
109
110/**
111 * Read packets from vmnet interface and write them
112 * to temporary buffers in VmnetState.
113 *
114 * Returns read packets number (may be 0) on success,
115 * -1 on error
116 */
117static int vmnet_read_packets(VmnetState *s)
118{
119    assert(s->packets_send_current_pos == s->packets_send_end_pos);
120
121    struct vmpktdesc *packets = s->packets_buf;
122    vmnet_return_t status;
123    int i;
124
125    /* Read as many packets as present */
126    s->packets_send_current_pos = 0;
127    s->packets_send_end_pos = VMNET_PACKETS_LIMIT;
128    for (i = 0; i < s->packets_send_end_pos; ++i) {
129        packets[i].vm_pkt_size = s->max_packet_size;
130        packets[i].vm_pkt_iovcnt = 1;
131        packets[i].vm_flags = 0;
132    }
133
134    status = vmnet_read(s->vmnet_if, packets, &s->packets_send_end_pos);
135    if (status != VMNET_SUCCESS) {
136        error_printf("vmnet: read failed: %s\n",
137                     vmnet_status_map_str(status));
138        s->packets_send_current_pos = 0;
139        s->packets_send_end_pos = 0;
140        return -1;
141    }
142    return s->packets_send_end_pos;
143}
144
145
146/**
147 * Write packets from temporary buffers in VmnetState
148 * to QEMU.
149 */
150static void vmnet_write_packets_to_qemu(VmnetState *s)
151{
152    while (s->packets_send_current_pos < s->packets_send_end_pos) {
153        ssize_t size = qemu_send_packet_async(&s->nc,
154                                      s->iov_buf[s->packets_send_current_pos].iov_base,
155                                      s->packets_buf[s->packets_send_current_pos].vm_pkt_size,
156                                      vmnet_send_completed);
157
158        if (size == 0) {
159            /* QEMU is not ready to consume more packets -
160             * stop and wait for completion callback call */
161            return;
162        }
163        ++s->packets_send_current_pos;
164    }
165}
166
167
168/**
169 * Bottom half callback that transfers packets from vmnet interface
170 * to QEMU.
171 *
172 * The process of transferring packets is three-staged:
173 * 1. Handle vmnet event;
174 * 2. Read packets from vmnet interface into temporary buffer;
175 * 3. Write packets from temporary buffer to QEMU.
176 *
177 * QEMU may suspend this process on the last stage, returning 0 from
178 * qemu_send_packet_async function. If this happens, we should
179 * respectfully wait until it is ready to consume more packets,
180 * write left ones in temporary buffer and only after this
181 * continue reading more packets from vmnet interface.
182 *
183 * Packets to be transferred are stored into packets_buf,
184 * in the window [packets_send_current_pos..packets_send_end_pos)
185 * including current_pos, excluding end_pos.
186 *
187 * Thus, if QEMU is not ready, buffer is not read and
188 * packets_send_current_pos < packets_send_end_pos.
189 */
190static void vmnet_send_bh(void *opaque)
191{
192    NetClientState *nc = (NetClientState *) opaque;
193    VmnetState *s = DO_UPCAST(VmnetState, nc, nc);
194
195    /*
196     * Do nothing if QEMU is not ready - wait
197     * for completion callback invocation
198     */
199    if (s->packets_send_current_pos < s->packets_send_end_pos) {
200        return;
201    }
202
203    /* Read packets from vmnet interface */
204    if (vmnet_read_packets(s) > 0) {
205        /* Send them to QEMU */
206        vmnet_write_packets_to_qemu(s);
207    }
208}
209
210
211/**
212 * Completion callback to be invoked by QEMU when it becomes
213 * ready to consume more packets.
214 */
215static void vmnet_send_completed(NetClientState *nc, ssize_t len)
216{
217    VmnetState *s = DO_UPCAST(VmnetState, nc, nc);
218
219    /* Callback is invoked eq queued packet is sent */
220    ++s->packets_send_current_pos;
221
222    /* Complete sending packets left in VmnetState buffers */
223    vmnet_write_packets_to_qemu(s);
224
225    /* And read new ones from vmnet if VmnetState buffer is ready */
226    if (s->packets_send_current_pos < s->packets_send_end_pos) {
227        qemu_bh_schedule(s->send_bh);
228    }
229}
230
231
232static void vmnet_bufs_init(VmnetState *s)
233{
234    struct vmpktdesc *packets = s->packets_buf;
235    struct iovec *iov = s->iov_buf;
236    int i;
237
238    for (i = 0; i < VMNET_PACKETS_LIMIT; ++i) {
239        iov[i].iov_len = s->max_packet_size;
240        iov[i].iov_base = g_malloc0(iov[i].iov_len);
241        packets[i].vm_pkt_iov = iov + i;
242    }
243}
244
245
246int vmnet_if_create(NetClientState *nc,
247                    xpc_object_t if_desc,
248                    Error **errp)
249{
250    VmnetState *s = DO_UPCAST(VmnetState, nc, nc);
251    dispatch_semaphore_t if_created_sem = dispatch_semaphore_create(0);
252    __block vmnet_return_t if_status;
253
254    s->if_queue = dispatch_queue_create(
255        "org.qemu.vmnet.if_queue",
256        DISPATCH_QUEUE_SERIAL
257    );
258
259    xpc_dictionary_set_bool(
260        if_desc,
261        vmnet_allocate_mac_address_key,
262        false
263    );
264
265#ifdef DEBUG
266    qemu_log("vmnet.start.interface_desc:\n");
267    xpc_dictionary_apply(if_desc,
268                         ^bool(const char *k, xpc_object_t v) {
269                             char *desc = xpc_copy_description(v);
270                             qemu_log("  %s=%s\n", k, desc);
271                             free(desc);
272                             return true;
273                         });
274#endif /* DEBUG */
275
276    s->vmnet_if = vmnet_start_interface(
277        if_desc,
278        s->if_queue,
279        ^(vmnet_return_t status, xpc_object_t interface_param) {
280            if_status = status;
281            if (status != VMNET_SUCCESS || !interface_param) {
282                dispatch_semaphore_signal(if_created_sem);
283                return;
284            }
285
286#ifdef DEBUG
287            qemu_log("vmnet.start.interface_param:\n");
288            xpc_dictionary_apply(interface_param,
289                                 ^bool(const char *k, xpc_object_t v) {
290                                     char *desc = xpc_copy_description(v);
291                                     qemu_log("  %s=%s\n", k, desc);
292                                     free(desc);
293                                     return true;
294                                 });
295#endif /* DEBUG */
296
297            s->mtu = xpc_dictionary_get_uint64(
298                interface_param,
299                vmnet_mtu_key);
300            s->max_packet_size = xpc_dictionary_get_uint64(
301                interface_param,
302                vmnet_max_packet_size_key);
303
304            dispatch_semaphore_signal(if_created_sem);
305        });
306
307    if (s->vmnet_if == NULL) {
308        dispatch_release(s->if_queue);
309        dispatch_release(if_created_sem);
310        error_setg(errp,
311                   "unable to create interface with requested params");
312        return -1;
313    }
314
315    dispatch_semaphore_wait(if_created_sem, DISPATCH_TIME_FOREVER);
316    dispatch_release(if_created_sem);
317
318    if (if_status != VMNET_SUCCESS) {
319        dispatch_release(s->if_queue);
320        error_setg(errp,
321                   "cannot create vmnet interface: %s",
322                   vmnet_status_map_str(if_status));
323        return -1;
324    }
325
326    s->send_bh = aio_bh_new(qemu_get_aio_context(), vmnet_send_bh, nc);
327    vmnet_bufs_init(s);
328
329    s->packets_send_current_pos = 0;
330    s->packets_send_end_pos = 0;
331
332    vmnet_interface_set_event_callback(
333        s->vmnet_if,
334        VMNET_INTERFACE_PACKETS_AVAILABLE,
335        s->if_queue,
336        ^(interface_event_t event_id, xpc_object_t event) {
337            assert(event_id == VMNET_INTERFACE_PACKETS_AVAILABLE);
338            /*
339             * This function is being called from a non qemu thread, so
340             * we only schedule a BH, and do the rest of the io completion
341             * handling from vmnet_send_bh() which runs in a qemu context.
342             */
343            qemu_bh_schedule(s->send_bh);
344        });
345
346    return 0;
347}
348
349
350void vmnet_cleanup_common(NetClientState *nc)
351{
352    VmnetState *s = DO_UPCAST(VmnetState, nc, nc);
353    dispatch_semaphore_t if_stopped_sem;
354
355    if (s->vmnet_if == NULL) {
356        return;
357    }
358
359    if_stopped_sem = dispatch_semaphore_create(0);
360    vmnet_stop_interface(
361        s->vmnet_if,
362        s->if_queue,
363        ^(vmnet_return_t status) {
364            assert(status == VMNET_SUCCESS);
365            dispatch_semaphore_signal(if_stopped_sem);
366        });
367    dispatch_semaphore_wait(if_stopped_sem, DISPATCH_TIME_FOREVER);
368
369    qemu_purge_queued_packets(nc);
370
371    qemu_bh_delete(s->send_bh);
372    dispatch_release(if_stopped_sem);
373    dispatch_release(s->if_queue);
374
375    for (int i = 0; i < VMNET_PACKETS_LIMIT; ++i) {
376        g_free(s->iov_buf[i].iov_base);
377    }
378}
379