1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
/*
* Xen stolen ticks accounting.
*/
#include <linux/kernel.h>
#include <linux/kernel_stat.h>
#include <linux/math64.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <asm/paravirt.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
#include <xen/events.h>
#include <xen/features.h>
#include <xen/interface/xen.h>
#include <xen/interface/vcpu.h>
#include <xen/xen-ops.h>
/* runstate info updated by Xen */
static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate);
static DEFINE_PER_CPU(u64[4], old_runstate_time);
/* return an consistent snapshot of 64-bit time/counter value */
static u64 get64(const u64 *p)
{
u64 ret;
if (BITS_PER_LONG < 64) {
u32 *p32 = (u32 *)p;
u32 h, l, h2;
/*
* Read high then low, and then make sure high is
* still the same; this will only loop if low wraps
* and carries into high.
* XXX some clean way to make this endian-proof?
*/
do {
h = READ_ONCE(p32[1]);
l = READ_ONCE(p32[0]);
h2 = READ_ONCE(p32[1]);
} while(h2 != h);
ret = (((u64)h) << 32) | l;
} else
ret = READ_ONCE(*p);
return ret;
}
static void xen_get_runstate_snapshot_cpu_delta(
struct vcpu_runstate_info *res, unsigned int cpu)
{
u64 state_time;
struct vcpu_runstate_info *state;
BUG_ON(preemptible());
state = per_cpu_ptr(&xen_runstate, cpu);
do {
state_time = get64(&state->state_entry_time);
rmb(); /* Hypervisor might update data. */
*res = READ_ONCE(*state);
rmb(); /* Hypervisor might update data. */
} while (get64(&state->state_entry_time) != state_time ||
(state_time & XEN_RUNSTATE_UPDATE));
}
static void xen_get_runstate_snapshot_cpu(struct vcpu_runstate_info *res,
unsigned int cpu)
{
int i;
xen_get_runstate_snapshot_cpu_delta(res, cpu);
for (i = 0; i < 4; i++)
res->time[i] += per_cpu(old_runstate_time, cpu)[i];
}
void xen_manage_runstate_time(int action)
{
static struct vcpu_runstate_info *runstate_delta;
struct vcpu_runstate_info state;
int cpu, i;
switch (action) {
case -1: /* backup runstate time before suspend */
if (unlikely(runstate_delta))
pr_warn_once("%s: memory leak as runstate_delta is not NULL\n",
__func__);
runstate_delta = kmalloc_array(num_possible_cpus(),
sizeof(*runstate_delta),
GFP_ATOMIC);
if (unlikely(!runstate_delta)) {
pr_warn("%s: failed to allocate runstate_delta\n",
__func__);
return;
}
for_each_possible_cpu(cpu) {
xen_get_runstate_snapshot_cpu_delta(&state, cpu);
memcpy(runstate_delta[cpu].time, state.time,
sizeof(runstate_delta[cpu].time));
}
break;
case 0: /* backup runstate time after resume */
if (unlikely(!runstate_delta)) {
pr_warn("%s: cannot accumulate runstate time as runstate_delta is NULL\n",
__func__);
return;
}
for_each_possible_cpu(cpu) {
for (i = 0; i < 4; i++)
per_cpu(old_runstate_time, cpu)[i] +=
runstate_delta[cpu].time[i];
}
break;
default: /* do not accumulate runstate time for checkpointing */
break;
}
if (action != -1 && runstate_delta) {
kfree(runstate_delta);
runstate_delta = NULL;
}
}
/*
* Runstate accounting
*/
void xen_get_runstate_snapshot(struct vcpu_runstate_info *res)
{
xen_get_runstate_snapshot_cpu(res, smp_processor_id());
}
/* return true when a vcpu could run but has no real cpu to run on */
bool xen_vcpu_stolen(int vcpu)
{
return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable;
}
u64 xen_steal_clock(int cpu)
{
struct vcpu_runstate_info state;
xen_get_runstate_snapshot_cpu(&state, cpu);
return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline];
}
void xen_setup_runstate_info(int cpu)
{
struct vcpu_register_runstate_memory_area area;
area.addr.v = &per_cpu(xen_runstate, cpu);
if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area,
xen_vcpu_nr(cpu), &area))
BUG();
}
void __init xen_time_setup_guest(void)
{
bool xen_runstate_remote;
xen_runstate_remote = !HYPERVISOR_vm_assist(VMASST_CMD_enable,
VMASST_TYPE_runstate_update_flag);
pv_time_ops.steal_clock = xen_steal_clock;
static_key_slow_inc(¶virt_steal_enabled);
if (xen_runstate_remote)
static_key_slow_inc(¶virt_steal_rq_enabled);
}
|
