1 #include "kvm/8250-serial.h" 2 3 #include "kvm/ioport.h" 4 #include "kvm/util.h" 5 #include "kvm/kvm.h" 6 7 #include <linux/serial_reg.h> 8 9 #include <stdbool.h> 10 #include <poll.h> 11 12 struct serial8250_device { 13 uint16_t iobase; 14 uint8_t irq; 15 16 uint8_t thr; 17 uint8_t dll; 18 uint8_t dlm; 19 uint8_t iir; 20 uint8_t ier; 21 uint8_t fcr; 22 uint8_t lcr; 23 uint8_t mcr; 24 uint8_t lsr; 25 uint8_t scr; 26 27 uint8_t counter; 28 }; 29 30 static struct serial8250_device devices[] = { 31 /* ttyS0 */ 32 [0] = { 33 .iobase = 0x3f8, 34 .irq = 4, 35 36 .lsr = UART_LSR_TEMT | UART_LSR_THRE, 37 }, 38 /* ttyS1 */ 39 [1] = { 40 .iobase = 0x2f8, 41 .irq = 3, 42 43 .iir = UART_IIR_NO_INT, 44 }, 45 /* ttyS2 */ 46 [2] = { 47 .iobase = 0x3e8, 48 .irq = 4, 49 50 .iir = UART_IIR_NO_INT, 51 }, 52 }; 53 54 static int read_char(int fd) 55 { 56 int c; 57 58 if (read(fd, &c, 1) < 0) 59 return -1; 60 61 return c; 62 } 63 64 static bool is_readable(int fd) 65 { 66 struct pollfd pollfd = (struct pollfd) { 67 .fd = fd, 68 .events = POLLIN, 69 }; 70 71 return poll(&pollfd, 1, 0) > 0; 72 } 73 74 /* 75 * Interrupts are injected for ttyS0 only. 76 */ 77 void serial8250__interrupt(struct kvm *self) 78 { 79 struct serial8250_device *dev = &devices[0]; 80 uint8_t new_iir; 81 82 dev->iir = UART_IIR_NO_INT; 83 84 /* No interrupts enabled. Exit... */ 85 if (!(dev->ier & (UART_IER_THRI|UART_IER_RDI))) 86 return; 87 88 new_iir = 0; 89 90 /* We're always good for guest sending data. */ 91 if (dev->ier & UART_IER_THRI) 92 new_iir |= UART_IIR_THRI; 93 94 /* Is there input in stdin to send to the guest? */ 95 if (!(dev->lsr & UART_LSR_DR) && is_readable(fileno(stdin))) { 96 int c; 97 98 c = read_char(fileno(stdin)); 99 if (c >= 0) { 100 dev->thr = c; 101 dev->lsr |= UART_LSR_DR; 102 new_iir |= UART_IIR_RDI; 103 } 104 } 105 106 /* Only send an IRQ if there's work to do. */ 107 if (new_iir) { 108 dev->counter = 0; 109 dev->iir = new_iir; 110 kvm__irq_line(self, dev->irq, 0); 111 kvm__irq_line(self, dev->irq, 1); 112 } 113 } 114 115 static struct serial8250_device *find_device(uint16_t port) 116 { 117 unsigned int i; 118 119 for (i = 0; i < ARRAY_SIZE(devices); i++) { 120 struct serial8250_device *dev = &devices[i]; 121 122 if (dev->iobase == (port & ~0x7)) 123 return dev; 124 } 125 return NULL; 126 } 127 128 static bool serial8250_out(struct kvm *self, uint16_t port, void *data, int size, uint32_t count) 129 { 130 struct serial8250_device *dev; 131 uint16_t offset; 132 133 dev = find_device(port); 134 if (!dev) 135 return false; 136 137 offset = port - dev->iobase; 138 139 if (dev->lcr & UART_LCR_DLAB) { 140 switch (offset) { 141 case UART_DLL: 142 dev->dll = ioport__read8(data); 143 break; 144 case UART_DLM: 145 dev->dlm = ioport__read8(data); 146 break; 147 case UART_FCR: 148 dev->fcr = ioport__read8(data); 149 break; 150 case UART_LCR: 151 dev->lcr = ioport__read8(data); 152 break; 153 default: 154 return false; 155 } 156 } else { 157 switch (offset) { 158 case UART_TX: { 159 char *p = data; 160 int i; 161 162 while (count--) { 163 for (i = 0; i < size; i++) 164 fprintf(stdout, "%c", *p++); 165 } 166 fflush(stdout); 167 168 if (dev->counter++ > 10) 169 dev->iir = UART_IIR_NO_INT; 170 171 break; 172 } 173 case UART_IER: 174 dev->ier = ioport__read8(data); 175 break; 176 case UART_FCR: 177 dev->fcr = ioport__read8(data); 178 break; 179 case UART_LCR: 180 dev->lcr = ioport__read8(data); 181 break; 182 case UART_MCR: 183 dev->mcr = ioport__read8(data); 184 break; 185 case UART_SCR: 186 dev->scr = ioport__read8(data); 187 break; 188 default: 189 return false; 190 } 191 } 192 193 return true; 194 } 195 196 static bool serial8250_in(struct kvm *self, uint16_t port, void *data, int size, uint32_t count) 197 { 198 struct serial8250_device *dev; 199 uint16_t offset; 200 201 dev = find_device(port); 202 if (!dev) 203 return false; 204 205 offset = port - dev->iobase; 206 207 if (dev->lcr & UART_LCR_DLAB) 208 return false; 209 210 switch (offset) { 211 case UART_TX: 212 if (dev->lsr & UART_LSR_DR) { 213 dev->iir = UART_IIR_NO_INT; 214 215 dev->lsr &= ~UART_LSR_DR; 216 ioport__write8(data, dev->thr); 217 } 218 break; 219 case UART_IER: 220 ioport__write8(data, dev->ier); 221 break; 222 case UART_IIR: 223 ioport__write8(data, dev->iir); 224 break; 225 case UART_LCR: 226 ioport__write8(data, dev->lcr); 227 break; 228 case UART_MCR: 229 ioport__write8(data, dev->mcr); 230 break; 231 case UART_LSR: 232 ioport__write8(data, dev->lsr); 233 break; 234 case UART_MSR: 235 ioport__write8(data, UART_MSR_CTS); 236 break; 237 case UART_SCR: 238 ioport__write8(data, dev->scr); 239 break; 240 default: 241 return false; 242 } 243 244 return true; 245 } 246 247 static struct ioport_operations serial8250_ops = { 248 .io_in = serial8250_in, 249 .io_out = serial8250_out, 250 }; 251 252 void serial8250__init(void) 253 { 254 unsigned int i; 255 256 for (i = 0; i < ARRAY_SIZE(devices); i++) { 257 struct serial8250_device *dev = &devices[i]; 258 259 ioport__register(dev->iobase, &serial8250_ops, 8); 260 } 261 } 262