hw/char/spapr_vty.c

   1 #include "qemu/osdep.h"
   2 #include "qemu/error-report.h"
   3 #include "qemu/module.h"
   4 #include "qapi/error.h"
   5 #include "cpu.h"
   6 #include "migration/vmstate.h"
   7 #include "chardev/char-fe.h"
   8 #include "hw/ppc/spapr.h"
   9 #include "hw/ppc/spapr_vio.h"
  10 #include "hw/qdev-properties.h"
  11 #include "hw/qdev-properties-system.h"
  12 #include "qom/object.h"
  13
  14 #define VTERM_BUFSIZE   16
  15
  16 struct SpaprVioVty {
  17     SpaprVioDevice sdev;
  18     CharBackend chardev;
  19     uint32_t in, out;
  20     uint8_t buf[VTERM_BUFSIZE];
  21 };
  22
  23 #define TYPE_VIO_SPAPR_VTY_DEVICE "spapr-vty"
  24 OBJECT_DECLARE_SIMPLE_TYPE(SpaprVioVty, VIO_SPAPR_VTY_DEVICE)
  25
  26 static int vty_can_receive(void *opaque)
  27 {
  28     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(opaque);
  29
  30     return VTERM_BUFSIZE - (dev->in - dev->out);
  31 }
  32
  33 static void vty_receive(void *opaque, const uint8_t *buf, int size)
  34 {
  35     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(opaque);
  36     int i;
  37
  38     if ((dev->in == dev->out) && size) {
  39         /* toggle line to simulate edge interrupt */
  40         spapr_vio_irq_pulse(&dev->sdev);
  41     }
  42     for (i = 0; i < size; i++) {
  43         if (dev->in - dev->out >= VTERM_BUFSIZE) {
  44             static bool reported;
  45             if (!reported) {
  46                 error_report("VTY input buffer exhausted - characters dropped."
  47                              " (input size = %i)", size);
  48                 reported = true;
  49             }
  50             break;
  51         }
  52         dev->buf[dev->in++ % VTERM_BUFSIZE] = buf[i];
  53     }
  54 }
  55
  56 static int vty_getchars(SpaprVioDevice *sdev, uint8_t *buf, int max)
  57 {
  58     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);
  59     int n = 0;
  60
  61     while ((n < max) && (dev->out != dev->in)) {
  62         /*
  63          * Long ago, PowerVM's vty implementation had a bug where it
  64          * inserted a \0 after every \r going to the guest.  Existing
  65          * guests have a workaround for this which removes every \0
  66          * immediately following a \r.  To avoid triggering this
  67          * workaround, we stop before inserting a \0 if the preceding
  68          * character in the output buffer is a \r.
  69          */
  70         if (n > 0 && (buf[n - 1] == '\r') &&
  71                 (dev->buf[dev->out % VTERM_BUFSIZE] == '\0')) {
  72             break;
  73         }
  74         buf[n++] = dev->buf[dev->out++ % VTERM_BUFSIZE];
  75     }
  76
  77     qemu_chr_fe_accept_input(&dev->chardev);
  78
  79     return n;
  80 }
  81
  82 void vty_putchars(SpaprVioDevice *sdev, uint8_t *buf, int len)
  83 {
  84     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);
  85
  86     /* XXX this blocks entire thread. Rewrite to use
  87      * qemu_chr_fe_write and background I/O callbacks */
  88     qemu_chr_fe_write_all(&dev->chardev, buf, len);
  89 }
  90
  91 static void spapr_vty_realize(SpaprVioDevice *sdev, Error **errp)
  92 {
  93     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);
  94
  95     if (!qemu_chr_fe_backend_connected(&dev->chardev)) {
  96         error_setg(errp, "chardev property not set");
  97         return;
  98     }
  99
 100     qemu_chr_fe_set_handlers(&dev->chardev, vty_can_receive,
 101                              vty_receive, NULL, NULL, dev, NULL, true);
 102 }
 103
 104 /* Forward declaration */
 105 static target_ulong h_put_term_char(PowerPCCPU *cpu, SpaprMachineState *spapr,
 106                                     target_ulong opcode, target_ulong *args)
 107 {
 108     target_ulong reg = args[0];
 109     target_ulong len = args[1];
 110     target_ulong char0_7 = args[2];
 111     target_ulong char8_15 = args[3];
 112     SpaprVioDevice *sdev;
 113     uint8_t buf[16];
 114
 115     sdev = vty_lookup(spapr, reg);
 116     if (!sdev) {
 117         return H_PARAMETER;
 118     }
 119
 120     if (len > 16) {
 121         return H_PARAMETER;
 122     }
 123
 124     *((uint64_t *)buf) = cpu_to_be64(char0_7);
 125     *((uint64_t *)buf + 1) = cpu_to_be64(char8_15);
 126
 127     vty_putchars(sdev, buf, len);
 128
 129     return H_SUCCESS;
 130 }
 131
 132 static target_ulong h_get_term_char(PowerPCCPU *cpu, SpaprMachineState *spapr,
 133                                     target_ulong opcode, target_ulong *args)
 134 {
 135     target_ulong reg = args[0];
 136     target_ulong *len = args + 0;
 137     target_ulong *char0_7 = args + 1;
 138     target_ulong *char8_15 = args + 2;
 139     SpaprVioDevice *sdev;
 140     uint8_t buf[16];
 141
 142     sdev = vty_lookup(spapr, reg);
 143     if (!sdev) {
 144         return H_PARAMETER;
 145     }
 146
 147     *len = vty_getchars(sdev, buf, sizeof(buf));
 148     if (*len < 16) {
 149         memset(buf + *len, 0, 16 - *len);
 150     }
 151
 152     *char0_7 = be64_to_cpu(*((uint64_t *)buf));
 153     *char8_15 = be64_to_cpu(*((uint64_t *)buf + 1));
 154
 155     return H_SUCCESS;
 156 }
 157
 158 void spapr_vty_create(SpaprVioBus *bus, Chardev *chardev)
 159 {
 160     DeviceState *dev;
 161
 162     dev = qdev_new("spapr-vty");
 163     qdev_prop_set_chr(dev, "chardev", chardev);
 164     qdev_realize_and_unref(dev, &bus->bus, &error_fatal);
 165 }
 166
 167 static Property spapr_vty_properties[] = {
 168     DEFINE_SPAPR_PROPERTIES(SpaprVioVty, sdev),
 169     DEFINE_PROP_CHR("chardev", SpaprVioVty, chardev),
 170     DEFINE_PROP_END_OF_LIST(),
 171 };
 172
 173 static const VMStateDescription vmstate_spapr_vty = {
 174     .name = "spapr_vty",
 175     .version_id = 1,
 176     .minimum_version_id = 1,
 177     .fields = (VMStateField[]) {
 178         VMSTATE_SPAPR_VIO(sdev, SpaprVioVty),
 179
 180         VMSTATE_UINT32(in, SpaprVioVty),
 181         VMSTATE_UINT32(out, SpaprVioVty),
 182         VMSTATE_BUFFER(buf, SpaprVioVty),
 183         VMSTATE_END_OF_LIST()
 184     },
 185 };
 186
 187 static void spapr_vty_class_init(ObjectClass *klass, void *data)
 188 {
 189     DeviceClass *dc = DEVICE_CLASS(klass);
 190     SpaprVioDeviceClass *k = VIO_SPAPR_DEVICE_CLASS(klass);
 191
 192     k->realize = spapr_vty_realize;
 193     k->dt_name = "vty";
 194     k->dt_type = "serial";
 195     k->dt_compatible = "hvterm1";
 196     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
 197     device_class_set_props(dc, spapr_vty_properties);
 198     dc->vmsd = &vmstate_spapr_vty;
 199 }
 200
 201 static const TypeInfo spapr_vty_info = {
 202     .name          = TYPE_VIO_SPAPR_VTY_DEVICE,
 203     .parent        = TYPE_VIO_SPAPR_DEVICE,
 204     .instance_size = sizeof(SpaprVioVty),
 205     .class_init    = spapr_vty_class_init,
 206 };
 207
 208 SpaprVioDevice *spapr_vty_get_default(SpaprVioBus *bus)
 209 {
 210     SpaprVioDevice *sdev, *selected;
 211     BusChild *kid;
 212
 213     /*
 214      * To avoid the console bouncing around we want one VTY to be
 215      * the "default". We haven't really got anything to go on, so
 216      * arbitrarily choose the one with the lowest reg value.
 217      */
 218
 219     selected = NULL;
 220     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
 221         DeviceState *iter = kid->child;
 222
 223         /* Only look at VTY devices */
 224         if (!object_dynamic_cast(OBJECT(iter), TYPE_VIO_SPAPR_VTY_DEVICE)) {
 225             continue;
 226         }
 227
 228         sdev = VIO_SPAPR_DEVICE(iter);
 229
 230         /* First VTY we've found, so it is selected for now */
 231         if (!selected) {
 232             selected = sdev;
 233             continue;
 234         }
 235
 236         /* Choose VTY with lowest reg value */
 237         if (sdev->reg < selected->reg) {
 238             selected = sdev;
 239         }
 240     }
 241
 242     return selected;
 243 }
 244
 245 SpaprVioDevice *vty_lookup(SpaprMachineState *spapr, target_ulong reg)
 246 {
 247     SpaprVioDevice *sdev;
 248
 249     sdev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
 250     if (!sdev && reg == 0) {
 251         /* Hack for kernel early debug, which always specifies reg==0.
 252          * We search all VIO devices, and grab the vty with the lowest
 253          * reg.  This attempts to mimic existing PowerVM behaviour
 254          * (early debug does work there, despite having no vty with
 255          * reg==0. */
 256         return spapr_vty_get_default(spapr->vio_bus);
 257     }
 258
 259     if (!object_dynamic_cast(OBJECT(sdev), TYPE_VIO_SPAPR_VTY_DEVICE)) {
 260         return NULL;
 261     }
 262
 263     return sdev;
 264 }
 265
 266 static void spapr_vty_register_types(void)
 267 {
 268     spapr_register_hypercall(H_PUT_TERM_CHAR, h_put_term_char);
 269     spapr_register_hypercall(H_GET_TERM_CHAR, h_get_term_char);
 270     type_register_static(&spapr_vty_info);
 271 }
 272
 273 type_init(spapr_vty_register_types)