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1 /*
2 * QEMU Hyper-V VMBus
3 *
4 * Copyright (c) 2017-2018 Virtuozzo International GmbH.
5 *
6 * This work is licensed under the terms of the GNU GPL, version 2 or later.
7 * See the COPYING file in the top-level directory.
8 */
9
10 #ifndef HW_HYPERV_VMBUS_H
11 #define HW_HYPERV_VMBUS_H
12
13 #include "system/system.h"
14 #include "system/dma.h"
15 #include "hw/core/qdev.h"
16 #include "migration/vmstate.h"
17 #include "hw/hyperv/vmbus-proto.h"
18 #include "qemu/uuid.h"
19 #include "qom/object.h"
20
21 #define TYPE_VMBUS_DEVICE "vmbus-dev"
22
23 OBJECT_DECLARE_TYPE(VMBusDevice, VMBusDeviceClass,
24 VMBUS_DEVICE)
25
26 #define TYPE_VMBUS "vmbus"
27 OBJECT_DECLARE_SIMPLE_TYPE(VMBus, VMBUS)
28
29 /*
30 * Object wrapping a GPADL -- GPA Descriptor List -- an array of guest physical
31 * pages, to be used for various buffers shared between the host and the guest.
32 */
33 typedef struct VMBusGpadl VMBusGpadl;
34 /*
35 * VMBus channel -- a pair of ring buffers for either direction, placed within
36 * one GPADL, and the associated notification means.
37 */
38 typedef struct VMBusChannel VMBusChannel;
39 /*
40 * Base class for VMBus devices. Includes one or more channels. Identified by
41 * class GUID and instance GUID.
42 */
43
44 typedef void(*VMBusChannelNotifyCb)(struct VMBusChannel *chan);
45
46 struct VMBusDeviceClass {
47 DeviceClass parent;
48
49 QemuUUID classid;
50 QemuUUID instanceid; /* Fixed UUID for singleton devices */
51 uint16_t channel_flags;
52 uint16_t mmio_size_mb;
53
54 /* Extensions to standard device callbacks */
55 void (*vmdev_realize)(VMBusDevice *vdev, Error **errp);
56 void (*vmdev_unrealize)(VMBusDevice *vdev);
57 void (*vmdev_reset)(VMBusDevice *vdev);
58 /*
59 * Calculate the number of channels based on the device properties. Called
60 * at realize time.
61 **/
62 uint16_t (*num_channels)(VMBusDevice *vdev);
63 /*
64 * Device-specific actions to complete the otherwise successful process of
65 * opening a channel.
66 * Return 0 on success, -errno on failure.
67 */
68 int (*open_channel)(VMBusChannel *chan);
69 /*
70 * Device-specific actions to perform before closing a channel.
71 */
72 void (*close_channel)(VMBusChannel *chan);
73 /*
74 * Main device worker; invoked in response to notifications from either
75 * side, when there's work to do with the data in the channel ring buffers.
76 */
77 VMBusChannelNotifyCb chan_notify_cb;
78 };
79
80 struct VMBusDevice {
81 DeviceState parent;
82 QemuUUID instanceid;
83 uint16_t num_channels;
84 VMBusChannel *channels;
85 AddressSpace *dma_as;
86 };
87
88 extern const VMStateDescription vmstate_vmbus_dev;
89
90 /*
91 * A unit of work parsed out of a message in the receive (i.e. guest->host)
92 * ring buffer of a channel. It's supposed to be subclassed (through
93 * embedding) by the specific devices.
94 */
95 typedef struct VMBusChanReq {
96 VMBusChannel *chan;
97 uint16_t pkt_type;
98 uint32_t msglen;
99 void *msg;
100 uint64_t transaction_id;
101 bool need_comp;
102 QEMUSGList sgl;
103 } VMBusChanReq;
104
105 VMBusDevice *vmbus_channel_device(VMBusChannel *chan);
106 VMBusChannel *vmbus_device_channel(VMBusDevice *dev, uint32_t chan_idx);
107 uint32_t vmbus_channel_idx(VMBusChannel *chan);
108 bool vmbus_channel_is_open(VMBusChannel *chan);
109
110 /*
111 * Notify (on guest's behalf) the host side of the channel that there's data in
112 * the ringbuffer to process.
113 */
114 void vmbus_channel_notify_host(VMBusChannel *chan);
115
116 /*
117 * Reserve space for a packet in the send (i.e. host->guest) ringbuffer. If
118 * there isn't enough room, indicate that to the guest, to be notified when it
119 * becomes available.
120 * Return 0 on success, negative errno on failure.
121 * The ringbuffer indices are NOT updated, the requested space indicator may.
122 */
123 int vmbus_channel_reserve(VMBusChannel *chan,
124 uint32_t desclen, uint32_t msglen);
125
126 /*
127 * Send a packet to the guest. The space for the packet MUST be reserved
128 * first.
129 * Return total number of bytes placed in the send ringbuffer on success,
130 * negative errno on failure.
131 * The ringbuffer indices are updated on success, and the guest is signaled if
132 * needed.
133 */
134 ssize_t vmbus_channel_send(VMBusChannel *chan, uint16_t pkt_type,
135 void *desc, uint32_t desclen,
136 void *msg, uint32_t msglen,
137 bool need_comp, uint64_t transaction_id);
138
139 /*
140 * Prepare to fetch a batch of packets from the receive ring buffer.
141 * Return 0 on success, negative errno on failure.
142 */
143 int vmbus_channel_recv_start(VMBusChannel *chan);
144
145 /*
146 * Shortcut for a common case of sending a simple completion packet with no
147 * auxiliary descriptors.
148 */
149 ssize_t vmbus_channel_send_completion(VMBusChanReq *req,
150 void *msg, uint32_t msglen);
151
152 /*
153 * Peek at the receive (i.e. guest->host) ring buffer and extract a unit of
154 * work (a device-specific subclass of VMBusChanReq) from a packet if there's
155 * one.
156 * Return an allocated buffer, containing the request of @size with filled
157 * VMBusChanReq at the beginning, followed by the message payload, or NULL on
158 * failure.
159 * The ringbuffer indices are NOT updated, nor is the private copy of the read
160 * index.
161 */
162 void *vmbus_channel_recv_peek(VMBusChannel *chan, uint32_t size);
163
164 /*
165 * Update the private copy of the read index once the preceding peek is deemed
166 * successful.
167 * The ringbuffer indices are NOT updated.
168 */
169 void vmbus_channel_recv_pop(VMBusChannel *chan);
170
171 /*
172 * Propagate the private copy of the read index into the receive ring buffer,
173 * and thus complete the reception of a series of packets. Notify guest if
174 * needed.
175 * Return the number of bytes popped off the receive ring buffer by the
176 * preceding recv_peek/recv_pop calls on success, negative errno on failure.
177 */
178 ssize_t vmbus_channel_recv_done(VMBusChannel *chan);
179
180 /*
181 * Free the request allocated by vmbus_channel_recv_peek, together with its
182 * fields.
183 */
184 void vmbus_free_req(void *req);
185
186 /*
187 * Find and reference a GPADL by @gpadl_id.
188 * If not found return NULL.
189 */
190 VMBusGpadl *vmbus_get_gpadl(VMBusChannel *chan, uint32_t gpadl_id);
191
192 /*
193 * Unreference @gpadl. If the reference count drops to zero, free it.
194 * @gpadl may be NULL, in which case nothing is done.
195 */
196 void vmbus_put_gpadl(VMBusGpadl *gpadl);
197
198 /*
199 * Calculate total length in bytes of @gpadl.
200 * @gpadl must be valid.
201 */
202 uint32_t vmbus_gpadl_len(VMBusGpadl *gpadl);
203
204 /*
205 * Copy data from @iov to @gpadl at offset @off.
206 * Return the number of bytes copied, or a negative status on failure.
207 */
208 ssize_t vmbus_iov_to_gpadl(VMBusChannel *chan, VMBusGpadl *gpadl, uint32_t off,
209 const struct iovec *iov, size_t iov_cnt);
210
211 /*
212 * Map SGList contained in the request @req, at offset @off and no more than
213 * @len bytes, for io in direction @dir, and populate @iov with the mapped
214 * iovecs.
215 * Return the number of iovecs mapped, or negative status on failure.
216 */
217 int vmbus_map_sgl(VMBusChanReq *req, DMADirection dir, struct iovec *iov,
218 unsigned iov_cnt, size_t len, size_t off);
219
220 /*
221 * Unmap *iov mapped with vmbus_map_sgl, marking the number of bytes @accessed.
222 */
223 void vmbus_unmap_sgl(VMBusChanReq *req, DMADirection dir, struct iovec *iov,
224 unsigned iov_cnt, size_t accessed);
225
226 #endif