14a27fd15SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
2108fc825SYoshihiro YUNOMAE /*
3108fc825SYoshihiro YUNOMAE * Read/write thread of a guest agent for virtio-trace
4108fc825SYoshihiro YUNOMAE *
5108fc825SYoshihiro YUNOMAE * Copyright (C) 2012 Hitachi, Ltd.
6108fc825SYoshihiro YUNOMAE * Created by Yoshihiro Yunomae <yoshihiro.yunomae.ez@hitachi.com>
7108fc825SYoshihiro YUNOMAE * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
8108fc825SYoshihiro YUNOMAE */
9108fc825SYoshihiro YUNOMAE
10108fc825SYoshihiro YUNOMAE #define _GNU_SOURCE
11108fc825SYoshihiro YUNOMAE #include <fcntl.h>
12108fc825SYoshihiro YUNOMAE #include <stdio.h>
13108fc825SYoshihiro YUNOMAE #include <stdlib.h>
14108fc825SYoshihiro YUNOMAE #include <unistd.h>
15108fc825SYoshihiro YUNOMAE #include <sys/syscall.h>
16108fc825SYoshihiro YUNOMAE #include "trace-agent.h"
17108fc825SYoshihiro YUNOMAE
18108fc825SYoshihiro YUNOMAE #define READ_WAIT_USEC 100000
19108fc825SYoshihiro YUNOMAE
rw_thread_info_new(void)20108fc825SYoshihiro YUNOMAE void *rw_thread_info_new(void)
21108fc825SYoshihiro YUNOMAE {
22108fc825SYoshihiro YUNOMAE struct rw_thread_info *rw_ti;
23108fc825SYoshihiro YUNOMAE
24108fc825SYoshihiro YUNOMAE rw_ti = zalloc(sizeof(struct rw_thread_info));
25108fc825SYoshihiro YUNOMAE if (rw_ti == NULL) {
26108fc825SYoshihiro YUNOMAE pr_err("rw_thread_info zalloc error\n");
27108fc825SYoshihiro YUNOMAE exit(EXIT_FAILURE);
28108fc825SYoshihiro YUNOMAE }
29108fc825SYoshihiro YUNOMAE
30108fc825SYoshihiro YUNOMAE rw_ti->cpu_num = -1;
31108fc825SYoshihiro YUNOMAE rw_ti->in_fd = -1;
32108fc825SYoshihiro YUNOMAE rw_ti->out_fd = -1;
33108fc825SYoshihiro YUNOMAE rw_ti->read_pipe = -1;
34108fc825SYoshihiro YUNOMAE rw_ti->write_pipe = -1;
35108fc825SYoshihiro YUNOMAE rw_ti->pipe_size = PIPE_INIT;
36108fc825SYoshihiro YUNOMAE
37108fc825SYoshihiro YUNOMAE return rw_ti;
38108fc825SYoshihiro YUNOMAE }
39108fc825SYoshihiro YUNOMAE
rw_thread_init(int cpu,const char * in_path,const char * out_path,bool stdout_flag,unsigned long pipe_size,struct rw_thread_info * rw_ti)40108fc825SYoshihiro YUNOMAE void *rw_thread_init(int cpu, const char *in_path, const char *out_path,
41108fc825SYoshihiro YUNOMAE bool stdout_flag, unsigned long pipe_size,
42108fc825SYoshihiro YUNOMAE struct rw_thread_info *rw_ti)
43108fc825SYoshihiro YUNOMAE {
44108fc825SYoshihiro YUNOMAE int data_pipe[2];
45108fc825SYoshihiro YUNOMAE
46108fc825SYoshihiro YUNOMAE rw_ti->cpu_num = cpu;
47108fc825SYoshihiro YUNOMAE
48108fc825SYoshihiro YUNOMAE /* set read(input) fd */
49108fc825SYoshihiro YUNOMAE rw_ti->in_fd = open(in_path, O_RDONLY);
50108fc825SYoshihiro YUNOMAE if (rw_ti->in_fd == -1) {
51108fc825SYoshihiro YUNOMAE pr_err("Could not open in_fd (CPU:%d)\n", cpu);
52108fc825SYoshihiro YUNOMAE goto error;
53108fc825SYoshihiro YUNOMAE }
54108fc825SYoshihiro YUNOMAE
55108fc825SYoshihiro YUNOMAE /* set write(output) fd */
56108fc825SYoshihiro YUNOMAE if (!stdout_flag) {
57108fc825SYoshihiro YUNOMAE /* virtio-serial output mode */
58108fc825SYoshihiro YUNOMAE rw_ti->out_fd = open(out_path, O_WRONLY);
59108fc825SYoshihiro YUNOMAE if (rw_ti->out_fd == -1) {
60108fc825SYoshihiro YUNOMAE pr_err("Could not open out_fd (CPU:%d)\n", cpu);
61108fc825SYoshihiro YUNOMAE goto error;
62108fc825SYoshihiro YUNOMAE }
63108fc825SYoshihiro YUNOMAE } else
64108fc825SYoshihiro YUNOMAE /* stdout mode */
65108fc825SYoshihiro YUNOMAE rw_ti->out_fd = STDOUT_FILENO;
66108fc825SYoshihiro YUNOMAE
67108fc825SYoshihiro YUNOMAE if (pipe2(data_pipe, O_NONBLOCK) < 0) {
68108fc825SYoshihiro YUNOMAE pr_err("Could not create pipe in rw-thread(%d)\n", cpu);
69108fc825SYoshihiro YUNOMAE goto error;
70108fc825SYoshihiro YUNOMAE }
71108fc825SYoshihiro YUNOMAE
72108fc825SYoshihiro YUNOMAE /*
73108fc825SYoshihiro YUNOMAE * Size of pipe is 64kB in default based on fs/pipe.c.
74108fc825SYoshihiro YUNOMAE * To read/write trace data speedy, pipe size is changed.
75108fc825SYoshihiro YUNOMAE */
76108fc825SYoshihiro YUNOMAE if (fcntl(*data_pipe, F_SETPIPE_SZ, pipe_size) < 0) {
77108fc825SYoshihiro YUNOMAE pr_err("Could not change pipe size in rw-thread(%d)\n", cpu);
78108fc825SYoshihiro YUNOMAE goto error;
79108fc825SYoshihiro YUNOMAE }
80108fc825SYoshihiro YUNOMAE
81108fc825SYoshihiro YUNOMAE rw_ti->read_pipe = data_pipe[1];
82108fc825SYoshihiro YUNOMAE rw_ti->write_pipe = data_pipe[0];
83108fc825SYoshihiro YUNOMAE rw_ti->pipe_size = pipe_size;
84108fc825SYoshihiro YUNOMAE
85108fc825SYoshihiro YUNOMAE return NULL;
86108fc825SYoshihiro YUNOMAE
87108fc825SYoshihiro YUNOMAE error:
88108fc825SYoshihiro YUNOMAE exit(EXIT_FAILURE);
89108fc825SYoshihiro YUNOMAE }
90108fc825SYoshihiro YUNOMAE
91108fc825SYoshihiro YUNOMAE /* Bind a thread to a cpu */
bind_cpu(int cpu_num)92108fc825SYoshihiro YUNOMAE static void bind_cpu(int cpu_num)
93108fc825SYoshihiro YUNOMAE {
94108fc825SYoshihiro YUNOMAE cpu_set_t mask;
95108fc825SYoshihiro YUNOMAE
96108fc825SYoshihiro YUNOMAE CPU_ZERO(&mask);
97108fc825SYoshihiro YUNOMAE CPU_SET(cpu_num, &mask);
98108fc825SYoshihiro YUNOMAE
99108fc825SYoshihiro YUNOMAE /* bind my thread to cpu_num by assigning zero to the first argument */
100108fc825SYoshihiro YUNOMAE if (sched_setaffinity(0, sizeof(mask), &mask) == -1)
101108fc825SYoshihiro YUNOMAE pr_err("Could not set CPU#%d affinity\n", (int)cpu_num);
102108fc825SYoshihiro YUNOMAE }
103108fc825SYoshihiro YUNOMAE
rw_thread_main(void * thread_info)104108fc825SYoshihiro YUNOMAE static void *rw_thread_main(void *thread_info)
105108fc825SYoshihiro YUNOMAE {
106108fc825SYoshihiro YUNOMAE ssize_t rlen, wlen;
107108fc825SYoshihiro YUNOMAE ssize_t ret;
108108fc825SYoshihiro YUNOMAE struct rw_thread_info *ts = (struct rw_thread_info *)thread_info;
109108fc825SYoshihiro YUNOMAE
110108fc825SYoshihiro YUNOMAE bind_cpu(ts->cpu_num);
111108fc825SYoshihiro YUNOMAE
112108fc825SYoshihiro YUNOMAE while (1) {
113108fc825SYoshihiro YUNOMAE /* Wait for a read order of trace data by Host OS */
114108fc825SYoshihiro YUNOMAE if (!global_run_operation) {
115108fc825SYoshihiro YUNOMAE pthread_mutex_lock(&mutex_notify);
116108fc825SYoshihiro YUNOMAE pthread_cond_wait(&cond_wakeup, &mutex_notify);
117108fc825SYoshihiro YUNOMAE pthread_mutex_unlock(&mutex_notify);
118108fc825SYoshihiro YUNOMAE }
119108fc825SYoshihiro YUNOMAE
120108fc825SYoshihiro YUNOMAE if (global_sig_receive)
121108fc825SYoshihiro YUNOMAE break;
122108fc825SYoshihiro YUNOMAE
123108fc825SYoshihiro YUNOMAE /*
124108fc825SYoshihiro YUNOMAE * Each thread read trace_pipe_raw of each cpu bounding the
125108fc825SYoshihiro YUNOMAE * thread, so contention of multi-threads does not occur.
126108fc825SYoshihiro YUNOMAE */
127108fc825SYoshihiro YUNOMAE rlen = splice(ts->in_fd, NULL, ts->read_pipe, NULL,
128108fc825SYoshihiro YUNOMAE ts->pipe_size, SPLICE_F_MOVE | SPLICE_F_MORE);
129108fc825SYoshihiro YUNOMAE
130108fc825SYoshihiro YUNOMAE if (rlen < 0) {
131108fc825SYoshihiro YUNOMAE pr_err("Splice_read in rw-thread(%d)\n", ts->cpu_num);
132108fc825SYoshihiro YUNOMAE goto error;
133108fc825SYoshihiro YUNOMAE } else if (rlen == 0) {
134108fc825SYoshihiro YUNOMAE /*
135108fc825SYoshihiro YUNOMAE * If trace data do not exist or are unreadable not
136108fc825SYoshihiro YUNOMAE * for exceeding the page size, splice_read returns
137108fc825SYoshihiro YUNOMAE * NULL. Then, this waits for being filled the data in a
138108fc825SYoshihiro YUNOMAE * ring-buffer.
139108fc825SYoshihiro YUNOMAE */
140108fc825SYoshihiro YUNOMAE usleep(READ_WAIT_USEC);
141108fc825SYoshihiro YUNOMAE pr_debug("Read retry(cpu:%d)\n", ts->cpu_num);
142108fc825SYoshihiro YUNOMAE continue;
143108fc825SYoshihiro YUNOMAE }
144108fc825SYoshihiro YUNOMAE
145108fc825SYoshihiro YUNOMAE wlen = 0;
146108fc825SYoshihiro YUNOMAE
147108fc825SYoshihiro YUNOMAE do {
148108fc825SYoshihiro YUNOMAE ret = splice(ts->write_pipe, NULL, ts->out_fd, NULL,
149108fc825SYoshihiro YUNOMAE rlen - wlen,
150108fc825SYoshihiro YUNOMAE SPLICE_F_MOVE | SPLICE_F_MORE);
151108fc825SYoshihiro YUNOMAE
152108fc825SYoshihiro YUNOMAE if (ret < 0) {
153108fc825SYoshihiro YUNOMAE pr_err("Splice_write in rw-thread(%d)\n",
154108fc825SYoshihiro YUNOMAE ts->cpu_num);
155108fc825SYoshihiro YUNOMAE goto error;
156108fc825SYoshihiro YUNOMAE } else if (ret == 0)
157108fc825SYoshihiro YUNOMAE /*
158108fc825SYoshihiro YUNOMAE * When host reader is not in time for reading
159108fc825SYoshihiro YUNOMAE * trace data, guest will be stopped. This is
160108fc825SYoshihiro YUNOMAE * because char dev in QEMU is not supported
161108fc825SYoshihiro YUNOMAE * non-blocking mode. Then, writer might be
162108fc825SYoshihiro YUNOMAE * sleep in that case.
163108fc825SYoshihiro YUNOMAE * This sleep will be removed by supporting
164108fc825SYoshihiro YUNOMAE * non-blocking mode.
165108fc825SYoshihiro YUNOMAE */
166108fc825SYoshihiro YUNOMAE sleep(1);
167108fc825SYoshihiro YUNOMAE wlen += ret;
168108fc825SYoshihiro YUNOMAE } while (wlen < rlen);
169108fc825SYoshihiro YUNOMAE }
170108fc825SYoshihiro YUNOMAE
171108fc825SYoshihiro YUNOMAE return NULL;
172108fc825SYoshihiro YUNOMAE
173108fc825SYoshihiro YUNOMAE error:
174108fc825SYoshihiro YUNOMAE exit(EXIT_FAILURE);
175108fc825SYoshihiro YUNOMAE }
176108fc825SYoshihiro YUNOMAE
177108fc825SYoshihiro YUNOMAE
rw_thread_run(struct rw_thread_info * rw_ti)178108fc825SYoshihiro YUNOMAE pthread_t rw_thread_run(struct rw_thread_info *rw_ti)
179108fc825SYoshihiro YUNOMAE {
180108fc825SYoshihiro YUNOMAE int ret;
181108fc825SYoshihiro YUNOMAE pthread_t rw_thread_per_cpu;
182108fc825SYoshihiro YUNOMAE
183108fc825SYoshihiro YUNOMAE ret = pthread_create(&rw_thread_per_cpu, NULL, rw_thread_main, rw_ti);
184108fc825SYoshihiro YUNOMAE if (ret != 0) {
185108fc825SYoshihiro YUNOMAE pr_err("Could not create a rw thread(%d)\n", rw_ti->cpu_num);
186108fc825SYoshihiro YUNOMAE exit(EXIT_FAILURE);
187108fc825SYoshihiro YUNOMAE }
188108fc825SYoshihiro YUNOMAE
189108fc825SYoshihiro YUNOMAE return rw_thread_per_cpu;
190108fc825SYoshihiro YUNOMAE }
191