hw/char/spapr_vty.c - third_party/qemu - Git at Google

 #include "qemu/osdep.h"
 #include "qemu/error-report.h"
 #include "qemu/module.h"
 #include "qapi/error.h"
 #include "migration/vmstate.h"
 #include "chardev/char-fe.h"
 #include "hw/ppc/spapr.h"
 #include "hw/ppc/spapr_vio.h"
 #include "hw/qdev-properties.h"
 #include "hw/qdev-properties-system.h"
 #include "qom/object.h"

 #define VTERM_BUFSIZE   16

 struct SpaprVioVty {
     SpaprVioDevice sdev;
     CharBackend chardev;
     uint32_t in, out;
     uint8_t buf[VTERM_BUFSIZE];
 };

 #define TYPE_VIO_SPAPR_VTY_DEVICE "spapr-vty"
 OBJECT_DECLARE_SIMPLE_TYPE(SpaprVioVty, VIO_SPAPR_VTY_DEVICE)

 static int vty_can_receive(void *opaque)
 {
     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(opaque);

     return VTERM_BUFSIZE - (dev->in - dev->out);
 }

 static void vty_receive(void *opaque, const uint8_t *buf, int size)
 {
     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(opaque);
     int i;

     if ((dev->in == dev->out) && size) {
         /* toggle line to simulate edge interrupt */
         spapr_vio_irq_pulse(&dev->sdev);
     }
     for (i = 0; i < size; i++) {
         if (dev->in - dev->out >= VTERM_BUFSIZE) {
             static bool reported;
             if (!reported) {
                 error_report("VTY input buffer exhausted - characters dropped."
                              " (input size = %i)", size);
                 reported = true;
             }
             break;
         }
         dev->buf[dev->in++ % VTERM_BUFSIZE] = buf[i];
     }
 }

 static int vty_getchars(SpaprVioDevice *sdev, uint8_t *buf, int max)
 {
     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);
     int n = 0;

     while ((n < max) && (dev->out != dev->in)) {
         /*
          * Long ago, PowerVM's vty implementation had a bug where it
          * inserted a \0 after every \r going to the guest.  Existing
          * guests have a workaround for this which removes every \0
          * immediately following a \r.  To avoid triggering this
          * workaround, we stop before inserting a \0 if the preceding
          * character in the output buffer is a \r.
          */
         if (n > 0 && (buf[n - 1] == '\r') &&
                 (dev->buf[dev->out % VTERM_BUFSIZE] == '\0')) {
             break;
         }
         buf[n++] = dev->buf[dev->out++ % VTERM_BUFSIZE];
     }

     qemu_chr_fe_accept_input(&dev->chardev);

     return n;
 }

 void vty_putchars(SpaprVioDevice *sdev, uint8_t *buf, int len)
 {
     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);

     /* XXX this blocks entire thread. Rewrite to use
      * qemu_chr_fe_write and background I/O callbacks */
     qemu_chr_fe_write_all(&dev->chardev, buf, len);
 }

 static void spapr_vty_realize(SpaprVioDevice *sdev, Error **errp)
 {
     SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);

     if (!qemu_chr_fe_backend_connected(&dev->chardev)) {
         error_setg(errp, "chardev property not set");
         return;
     }

     qemu_chr_fe_set_handlers(&dev->chardev, vty_can_receive,
                              vty_receive, NULL, NULL, dev, NULL, true);
 }

 /* Forward declaration */
 static target_ulong h_put_term_char(PowerPCCPU *cpu, SpaprMachineState *spapr,
                                     target_ulong opcode, target_ulong *args)
 {
     target_ulong reg = args[0];
     target_ulong len = args[1];
     target_ulong char0_7 = args[2];
     target_ulong char8_15 = args[3];
     SpaprVioDevice *sdev;
     uint8_t buf[16];

     sdev = vty_lookup(spapr, reg);
     if (!sdev) {
         return H_PARAMETER;
     }

     if (len > 16) {
         return H_PARAMETER;
     }

     *((uint64_t *)buf) = cpu_to_be64(char0_7);
     *((uint64_t *)buf + 1) = cpu_to_be64(char8_15);

     vty_putchars(sdev, buf, len);

     return H_SUCCESS;
 }

 static target_ulong h_get_term_char(PowerPCCPU *cpu, SpaprMachineState *spapr,
                                     target_ulong opcode, target_ulong *args)
 {
     target_ulong reg = args[0];
     target_ulong *len = args + 0;
     target_ulong *char0_7 = args + 1;
     target_ulong *char8_15 = args + 2;
     SpaprVioDevice *sdev;
     uint8_t buf[16];

     sdev = vty_lookup(spapr, reg);
     if (!sdev) {
         return H_PARAMETER;
     }

     *len = vty_getchars(sdev, buf, sizeof(buf));
     if (*len < 16) {
         memset(buf + *len, 0, 16 - *len);
     }

     *char0_7 = be64_to_cpu(*((uint64_t *)buf));
     *char8_15 = be64_to_cpu(*((uint64_t *)buf + 1));

     return H_SUCCESS;
 }

 void spapr_vty_create(SpaprVioBus *bus, Chardev *chardev)
 {
     DeviceState *dev;

     dev = qdev_new("spapr-vty");
     qdev_prop_set_chr(dev, "chardev", chardev);
     qdev_realize_and_unref(dev, &bus->bus, &error_fatal);
 }

 static Property spapr_vty_properties[] = {
     DEFINE_SPAPR_PROPERTIES(SpaprVioVty, sdev),
     DEFINE_PROP_CHR("chardev", SpaprVioVty, chardev),
     DEFINE_PROP_END_OF_LIST(),
 };

 static const VMStateDescription vmstate_spapr_vty = {
     .name = "spapr_vty",
     .version_id = 1,
     .minimum_version_id = 1,
     .fields = (VMStateField[]) {
         VMSTATE_SPAPR_VIO(sdev, SpaprVioVty),

         VMSTATE_UINT32(in, SpaprVioVty),
         VMSTATE_UINT32(out, SpaprVioVty),
         VMSTATE_BUFFER(buf, SpaprVioVty),
         VMSTATE_END_OF_LIST()
     },
 };

 static void spapr_vty_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     SpaprVioDeviceClass *k = VIO_SPAPR_DEVICE_CLASS(klass);

     k->realize = spapr_vty_realize;
     k->dt_name = "vty";
     k->dt_type = "serial";
     k->dt_compatible = "hvterm1";
     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
     device_class_set_props(dc, spapr_vty_properties);
     dc->vmsd = &vmstate_spapr_vty;
 }

 static const TypeInfo spapr_vty_info = {
     .name          = TYPE_VIO_SPAPR_VTY_DEVICE,
     .parent        = TYPE_VIO_SPAPR_DEVICE,
     .instance_size = sizeof(SpaprVioVty),
     .class_init    = spapr_vty_class_init,
 };

 SpaprVioDevice *spapr_vty_get_default(SpaprVioBus *bus)
 {
     SpaprVioDevice *sdev, *selected;
     BusChild *kid;

     /*
      * To avoid the console bouncing around we want one VTY to be
      * the "default". We haven't really got anything to go on, so
      * arbitrarily choose the one with the lowest reg value.
      */

     selected = NULL;
     QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
         DeviceState *iter = kid->child;

         /* Only look at VTY devices */
         if (!object_dynamic_cast(OBJECT(iter), TYPE_VIO_SPAPR_VTY_DEVICE)) {
             continue;
         }

         sdev = VIO_SPAPR_DEVICE(iter);

         /* First VTY we've found, so it is selected for now */
         if (!selected) {
             selected = sdev;
             continue;
         }

         /* Choose VTY with lowest reg value */
         if (sdev->reg < selected->reg) {
             selected = sdev;
         }
     }

     return selected;
 }

 SpaprVioDevice *vty_lookup(SpaprMachineState *spapr, target_ulong reg)
 {
     SpaprVioDevice *sdev;

     sdev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
     if (!sdev && reg == 0) {
         /* Hack for kernel early debug, which always specifies reg==0.
          * We search all VIO devices, and grab the vty with the lowest
          * reg.  This attempts to mimic existing PowerVM behaviour
          * (early debug does work there, despite having no vty with
          * reg==0. */
         return spapr_vty_get_default(spapr->vio_bus);
     }

     if (!object_dynamic_cast(OBJECT(sdev), TYPE_VIO_SPAPR_VTY_DEVICE)) {
         return NULL;
     }

     return sdev;
 }

 static void spapr_vty_register_types(void)
 {
     spapr_register_hypercall(H_PUT_TERM_CHAR, h_put_term_char);
     spapr_register_hypercall(H_GET_TERM_CHAR, h_get_term_char);
     type_register_static(&spapr_vty_info);
 }

 type_init(spapr_vty_register_types)
	#include "qemu/osdep.h"
	#include "qemu/error-report.h"
	#include "qemu/module.h"
	#include "qapi/error.h"
	#include "migration/vmstate.h"
	#include "chardev/char-fe.h"
	#include "hw/ppc/spapr.h"
	#include "hw/ppc/spapr_vio.h"
	#include "hw/qdev-properties.h"
	#include "hw/qdev-properties-system.h"
	#include "qom/object.h"

	#define VTERM_BUFSIZE 16

	struct SpaprVioVty {
	SpaprVioDevice sdev;
	CharBackend chardev;
	uint32_t in, out;
	uint8_t buf[VTERM_BUFSIZE];
	};

	#define TYPE_VIO_SPAPR_VTY_DEVICE "spapr-vty"
	OBJECT_DECLARE_SIMPLE_TYPE(SpaprVioVty, VIO_SPAPR_VTY_DEVICE)

	static int vty_can_receive(void *opaque)
	{
	SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(opaque);

	return VTERM_BUFSIZE - (dev->in - dev->out);
	}

	static void vty_receive(void opaque, const uint8_t buf, int size)
	{
	SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(opaque);
	int i;

	if ((dev->in == dev->out) && size) {
	/* toggle line to simulate edge interrupt */
	spapr_vio_irq_pulse(&dev->sdev);
	}
	for (i = 0; i < size; i++) {
	if (dev->in - dev->out >= VTERM_BUFSIZE) {
	static bool reported;
	if (!reported) {
	error_report("VTY input buffer exhausted - characters dropped."
	" (input size = %i)", size);
	reported = true;
	}
	break;
	}
	dev->buf[dev->in++ % VTERM_BUFSIZE] = buf[i];
	}
	}

	static int vty_getchars(SpaprVioDevice sdev, uint8_t buf, int max)
	{
	SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);
	int n = 0;

	while ((n < max) && (dev->out != dev->in)) {
	/*
	* Long ago, PowerVM's vty implementation had a bug where it
	* inserted a \0 after every \r going to the guest. Existing
	* guests have a workaround for this which removes every \0
	* immediately following a \r. To avoid triggering this
	* workaround, we stop before inserting a \0 if the preceding
	* character in the output buffer is a \r.
	*/
	if (n > 0 && (buf[n - 1] == '\r') &&
	(dev->buf[dev->out % VTERM_BUFSIZE] == '\0')) {
	break;
	}
	buf[n++] = dev->buf[dev->out++ % VTERM_BUFSIZE];
	}

	qemu_chr_fe_accept_input(&dev->chardev);

	return n;
	}

	void vty_putchars(SpaprVioDevice sdev, uint8_t buf, int len)
	{
	SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);

	/* XXX this blocks entire thread. Rewrite to use
	* qemu_chr_fe_write and background I/O callbacks */
	qemu_chr_fe_write_all(&dev->chardev, buf, len);
	}

	static void spapr_vty_realize(SpaprVioDevice sdev, Error *errp)
	{
	SpaprVioVty *dev = VIO_SPAPR_VTY_DEVICE(sdev);

	if (!qemu_chr_fe_backend_connected(&dev->chardev)) {
	error_setg(errp, "chardev property not set");
	return;
	}

	qemu_chr_fe_set_handlers(&dev->chardev, vty_can_receive,
	vty_receive, NULL, NULL, dev, NULL, true);
	}

	/* Forward declaration */
	static target_ulong h_put_term_char(PowerPCCPU cpu, SpaprMachineState spapr,
	target_ulong opcode, target_ulong *args)
	{
	target_ulong reg = args[0];
	target_ulong len = args[1];
	target_ulong char0_7 = args[2];
	target_ulong char8_15 = args[3];
	SpaprVioDevice *sdev;
	uint8_t buf[16];

	sdev = vty_lookup(spapr, reg);
	if (!sdev) {
	return H_PARAMETER;
	}

	if (len > 16) {
	return H_PARAMETER;
	}

	((uint64_t )buf) = cpu_to_be64(char0_7);
	((uint64_t )buf + 1) = cpu_to_be64(char8_15);

	vty_putchars(sdev, buf, len);

	return H_SUCCESS;
	}

	static target_ulong h_get_term_char(PowerPCCPU cpu, SpaprMachineState spapr,
	target_ulong opcode, target_ulong *args)
	{
	target_ulong reg = args[0];
	target_ulong *len = args + 0;
	target_ulong *char0_7 = args + 1;
	target_ulong *char8_15 = args + 2;
	SpaprVioDevice *sdev;
	uint8_t buf[16];

	sdev = vty_lookup(spapr, reg);
	if (!sdev) {
	return H_PARAMETER;
	}

	*len = vty_getchars(sdev, buf, sizeof(buf));
	if (*len < 16) {
	memset(buf + len, 0, 16 - len);
	}

	char0_7 = be64_to_cpu(((uint64_t *)buf));
	char8_15 = be64_to_cpu(((uint64_t *)buf + 1));

	return H_SUCCESS;
	}

	void spapr_vty_create(SpaprVioBus bus, Chardev chardev)
	{
	DeviceState *dev;

	dev = qdev_new("spapr-vty");
	qdev_prop_set_chr(dev, "chardev", chardev);
	qdev_realize_and_unref(dev, &bus->bus, &error_fatal);
	}

	static Property spapr_vty_properties[] = {
	DEFINE_SPAPR_PROPERTIES(SpaprVioVty, sdev),
	DEFINE_PROP_CHR("chardev", SpaprVioVty, chardev),
	DEFINE_PROP_END_OF_LIST(),
	};

	static const VMStateDescription vmstate_spapr_vty = {
	.name = "spapr_vty",
	.version_id = 1,
	.minimum_version_id = 1,
	.fields = (VMStateField[]) {
	VMSTATE_SPAPR_VIO(sdev, SpaprVioVty),

	VMSTATE_UINT32(in, SpaprVioVty),
	VMSTATE_UINT32(out, SpaprVioVty),
	VMSTATE_BUFFER(buf, SpaprVioVty),
	VMSTATE_END_OF_LIST()
	},
	};

	static void spapr_vty_class_init(ObjectClass klass, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(klass);
	SpaprVioDeviceClass *k = VIO_SPAPR_DEVICE_CLASS(klass);

	k->realize = spapr_vty_realize;
	k->dt_name = "vty";
	k->dt_type = "serial";
	k->dt_compatible = "hvterm1";
	set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
	device_class_set_props(dc, spapr_vty_properties);
	dc->vmsd = &vmstate_spapr_vty;
	}

	static const TypeInfo spapr_vty_info = {
	.name = TYPE_VIO_SPAPR_VTY_DEVICE,
	.parent = TYPE_VIO_SPAPR_DEVICE,
	.instance_size = sizeof(SpaprVioVty),
	.class_init = spapr_vty_class_init,
	};

	SpaprVioDevice spapr_vty_get_default(SpaprVioBus bus)
	{
	SpaprVioDevice sdev, selected;
	BusChild *kid;

	/*
	* To avoid the console bouncing around we want one VTY to be
	* the "default". We haven't really got anything to go on, so
	* arbitrarily choose the one with the lowest reg value.
	*/

	selected = NULL;
	QTAILQ_FOREACH(kid, &bus->bus.children, sibling) {
	DeviceState *iter = kid->child;

	/* Only look at VTY devices */
	if (!object_dynamic_cast(OBJECT(iter), TYPE_VIO_SPAPR_VTY_DEVICE)) {
	continue;
	}

	sdev = VIO_SPAPR_DEVICE(iter);

	/* First VTY we've found, so it is selected for now */
	if (!selected) {
	selected = sdev;
	continue;
	}

	/* Choose VTY with lowest reg value */
	if (sdev->reg < selected->reg) {
	selected = sdev;
	}
	}

	return selected;
	}

	SpaprVioDevice vty_lookup(SpaprMachineState spapr, target_ulong reg)
	{
	SpaprVioDevice *sdev;

	sdev = spapr_vio_find_by_reg(spapr->vio_bus, reg);
	if (!sdev && reg == 0) {
	/* Hack for kernel early debug, which always specifies reg==0.
	* We search all VIO devices, and grab the vty with the lowest
	* reg. This attempts to mimic existing PowerVM behaviour
	* (early debug does work there, despite having no vty with
	* reg==0. */
	return spapr_vty_get_default(spapr->vio_bus);
	}

	if (!object_dynamic_cast(OBJECT(sdev), TYPE_VIO_SPAPR_VTY_DEVICE)) {
	return NULL;
	}

	return sdev;
	}

	static void spapr_vty_register_types(void)
	{
	spapr_register_hypercall(H_PUT_TERM_CHAR, h_put_term_char);
	spapr_register_hypercall(H_GET_TERM_CHAR, h_get_term_char);
	type_register_static(&spapr_vty_info);
	}

	type_init(spapr_vty_register_types)