Commit 4e4fa398 authored by Jan Kiszka's avatar Jan Kiszka Committed by Anthony Liguori
Browse files

qdev: Introduce lost tick policy property 



Potentially tick-generating timer devices will gain a common property:
lock_tick_policy. It allows to encode 4 different ways how to deal with
tick events the guest did not process in time:

discard - ignore lost ticks (e.g. if the guest compensates for them
          already)
delay   - replay all lost ticks in a row once the guest accepts them
          again
merge   - if multiple ticks are lost, all of them are merged into one
          which is replayed once the guest accepts it again
slew    - lost ticks are gradually replayed at a higher frequency than
          the original tick

Not all timer device will need to support all modes. However, all need
to accept the configuration via this common property.

Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
parent 67ed96f9

hw/qdev-properties.c

+55 −0
Original line number Diff line number Diff line
@@ -885,6 +885,55 @@ PropertyInfo qdev_prop_macaddr = { 
    .set   = set_generic,

};





/* --- lost tick policy --- */



static const struct {

    const char *name;

    LostTickPolicy code;

} lost_tick_policy_table[] = {

    { .name = "discard", .code = LOST_TICK_DISCARD },

    { .name = "delay", .code = LOST_TICK_DELAY },

    { .name = "merge", .code = LOST_TICK_MERGE },

    { .name = "slew", .code = LOST_TICK_SLEW },

};



static int parse_lost_tick_policy(DeviceState *dev, Property *prop,

                                  const char *str)

{

    LostTickPolicy *ptr = qdev_get_prop_ptr(dev, prop);

    int i;



    for (i = 0; i < ARRAY_SIZE(lost_tick_policy_table); i++) {

        if (!strcasecmp(str, lost_tick_policy_table[i].name)) {

            *ptr = lost_tick_policy_table[i].code;

            break;

        }

    }

    if (i == ARRAY_SIZE(lost_tick_policy_table)) {

        return -EINVAL;

    }

    return 0;

}



static int print_lost_tick_policy(DeviceState *dev, Property *prop, char *dest,

                                  size_t len)

{

    LostTickPolicy *ptr = qdev_get_prop_ptr(dev, prop);



    return snprintf(dest, len, "%s", lost_tick_policy_table[*ptr].name);

}



PropertyInfo qdev_prop_losttickpolicy = {

    .name  = "lost_tick_policy",

    .type  = PROP_TYPE_LOSTTICKPOLICY,

    .size  = sizeof(LostTickPolicy),

    .parse = parse_lost_tick_policy,

    .print = print_lost_tick_policy,

    .get   = get_generic,

    .set   = set_generic,

};



/* --- pci address --- */



/*
@@ -1127,6 +1176,12 @@ void qdev_prop_set_macaddr(DeviceState *dev, const char *name, uint8_t *value) 
    qdev_prop_set(dev, name, value, PROP_TYPE_MACADDR);

}



void qdev_prop_set_losttickpolicy(DeviceState *dev, const char *name,

                                  LostTickPolicy *value)

{

    qdev_prop_set(dev, name, value, PROP_TYPE_LOSTTICKPOLICY);

}



void qdev_prop_set_ptr(DeviceState *dev, const char *name, void *value)

{

    qdev_prop_set(dev, name, &value, PROP_TYPE_PTR);

hw/qdev.h

+7 −0
Original line number Diff line number Diff line
@@ -158,6 +158,7 @@ enum PropertyType { 
    PROP_TYPE_UINT64,

    PROP_TYPE_TADDR,

    PROP_TYPE_MACADDR,

    PROP_TYPE_LOSTTICKPOLICY,

    PROP_TYPE_DRIVE,

    PROP_TYPE_CHR,

    PROP_TYPE_STRING,
@@ -307,6 +308,7 @@ extern PropertyInfo qdev_prop_string; 
extern PropertyInfo qdev_prop_chr;

extern PropertyInfo qdev_prop_ptr;

extern PropertyInfo qdev_prop_macaddr;

extern PropertyInfo qdev_prop_losttickpolicy;

extern PropertyInfo qdev_prop_drive;

extern PropertyInfo qdev_prop_netdev;

extern PropertyInfo qdev_prop_vlan;
@@ -367,6 +369,9 @@ extern PropertyInfo qdev_prop_pci_devfn; 
    DEFINE_PROP(_n, _s, _f, qdev_prop_drive, BlockDriverState *)

#define DEFINE_PROP_MACADDR(_n, _s, _f)         \

    DEFINE_PROP(_n, _s, _f, qdev_prop_macaddr, MACAddr)

#define DEFINE_PROP_LOSTTICKPOLICY(_n, _s, _f, _d) \

    DEFINE_PROP_DEFAULT(_n, _s, _f, _d, qdev_prop_losttickpolicy, \

                        LostTickPolicy)



#define DEFINE_PROP_END_OF_LIST()               \

    {}
@@ -389,6 +394,8 @@ void qdev_prop_set_vlan(DeviceState *dev, const char *name, VLANState *value); 
int qdev_prop_set_drive(DeviceState *dev, const char *name, BlockDriverState *value) QEMU_WARN_UNUSED_RESULT;

void qdev_prop_set_drive_nofail(DeviceState *dev, const char *name, BlockDriverState *value);

void qdev_prop_set_macaddr(DeviceState *dev, const char *name, uint8_t *value);

void qdev_prop_set_losttickpolicy(DeviceState *dev, const char *name,

                                  LostTickPolicy *value);

/* FIXME: Remove opaque pointer properties.  */

void qdev_prop_set_ptr(DeviceState *dev, const char *name, void *value);

void qdev_prop_set_defaults(DeviceState *dev, Property *props);

qemu-common.h

+7 −0
Original line number Diff line number Diff line
@@ -250,6 +250,13 @@ typedef struct QEMUSGList QEMUSGList; 


typedef uint64_t pcibus_t;



typedef enum LostTickPolicy {

    LOST_TICK_DISCARD,

    LOST_TICK_DELAY,

    LOST_TICK_MERGE,

    LOST_TICK_SLEW,

} LostTickPolicy;



void tcg_exec_init(unsigned long tb_size);

bool tcg_enabled(void);