Loading...
1#include <linux/hardirq.h>
2
3#include <asm/x86_init.h>
4
5#include <xen/interface/xen.h>
6#include <xen/interface/sched.h>
7#include <xen/interface/vcpu.h>
8#include <xen/features.h>
9#include <xen/events.h>
10
11#include <asm/xen/hypercall.h>
12#include <asm/xen/hypervisor.h>
13
14#include "xen-ops.h"
15
16/*
17 * Force a proper event-channel callback from Xen after clearing the
18 * callback mask. We do this in a very simple manner, by making a call
19 * down into Xen. The pending flag will be checked by Xen on return.
20 */
21void xen_force_evtchn_callback(void)
22{
23 (void)HYPERVISOR_xen_version(0, NULL);
24}
25
26asmlinkage __visible unsigned long xen_save_fl(void)
27{
28 struct vcpu_info *vcpu;
29 unsigned long flags;
30
31 vcpu = this_cpu_read(xen_vcpu);
32
33 /* flag has opposite sense of mask */
34 flags = !vcpu->evtchn_upcall_mask;
35
36 /* convert to IF type flag
37 -0 -> 0x00000000
38 -1 -> 0xffffffff
39 */
40 return (-flags) & X86_EFLAGS_IF;
41}
42PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl);
43
44__visible void xen_restore_fl(unsigned long flags)
45{
46 struct vcpu_info *vcpu;
47
48 /* convert from IF type flag */
49 flags = !(flags & X86_EFLAGS_IF);
50
51 /* See xen_irq_enable() for why preemption must be disabled. */
52 preempt_disable();
53 vcpu = this_cpu_read(xen_vcpu);
54 vcpu->evtchn_upcall_mask = flags;
55
56 if (flags == 0) {
57 barrier(); /* unmask then check (avoid races) */
58 if (unlikely(vcpu->evtchn_upcall_pending))
59 xen_force_evtchn_callback();
60 preempt_enable();
61 } else
62 preempt_enable_no_resched();
63}
64PV_CALLEE_SAVE_REGS_THUNK(xen_restore_fl);
65
66asmlinkage __visible void xen_irq_disable(void)
67{
68 /* There's a one instruction preempt window here. We need to
69 make sure we're don't switch CPUs between getting the vcpu
70 pointer and updating the mask. */
71 preempt_disable();
72 this_cpu_read(xen_vcpu)->evtchn_upcall_mask = 1;
73 preempt_enable_no_resched();
74}
75PV_CALLEE_SAVE_REGS_THUNK(xen_irq_disable);
76
77asmlinkage __visible void xen_irq_enable(void)
78{
79 struct vcpu_info *vcpu;
80
81 /*
82 * We may be preempted as soon as vcpu->evtchn_upcall_mask is
83 * cleared, so disable preemption to ensure we check for
84 * events on the VCPU we are still running on.
85 */
86 preempt_disable();
87
88 vcpu = this_cpu_read(xen_vcpu);
89 vcpu->evtchn_upcall_mask = 0;
90
91 /* Doesn't matter if we get preempted here, because any
92 pending event will get dealt with anyway. */
93
94 barrier(); /* unmask then check (avoid races) */
95 if (unlikely(vcpu->evtchn_upcall_pending))
96 xen_force_evtchn_callback();
97
98 preempt_enable();
99}
100PV_CALLEE_SAVE_REGS_THUNK(xen_irq_enable);
101
102static void xen_safe_halt(void)
103{
104 /* Blocking includes an implicit local_irq_enable(). */
105 if (HYPERVISOR_sched_op(SCHEDOP_block, NULL) != 0)
106 BUG();
107}
108
109static void xen_halt(void)
110{
111 if (irqs_disabled())
112 HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
113 else
114 xen_safe_halt();
115}
116
117static const struct pv_irq_ops xen_irq_ops __initconst = {
118 .save_fl = PV_CALLEE_SAVE(xen_save_fl),
119 .restore_fl = PV_CALLEE_SAVE(xen_restore_fl),
120 .irq_disable = PV_CALLEE_SAVE(xen_irq_disable),
121 .irq_enable = PV_CALLEE_SAVE(xen_irq_enable),
122
123 .safe_halt = xen_safe_halt,
124 .halt = xen_halt,
125#ifdef CONFIG_X86_64
126 .adjust_exception_frame = xen_adjust_exception_frame,
127#endif
128};
129
130void __init xen_init_irq_ops(void)
131{
132 /* For PVH we use default pv_irq_ops settings. */
133 if (!xen_feature(XENFEAT_hvm_callback_vector))
134 pv_irq_ops = xen_irq_ops;
135 x86_init.irqs.intr_init = xen_init_IRQ;
136}
1#include <linux/hardirq.h>
2
3#include <asm/x86_init.h>
4
5#include <xen/interface/xen.h>
6#include <xen/interface/sched.h>
7#include <xen/interface/vcpu.h>
8
9#include <asm/xen/hypercall.h>
10#include <asm/xen/hypervisor.h>
11
12#include "xen-ops.h"
13
14/*
15 * Force a proper event-channel callback from Xen after clearing the
16 * callback mask. We do this in a very simple manner, by making a call
17 * down into Xen. The pending flag will be checked by Xen on return.
18 */
19void xen_force_evtchn_callback(void)
20{
21 (void)HYPERVISOR_xen_version(0, NULL);
22}
23
24static unsigned long xen_save_fl(void)
25{
26 struct vcpu_info *vcpu;
27 unsigned long flags;
28
29 vcpu = percpu_read(xen_vcpu);
30
31 /* flag has opposite sense of mask */
32 flags = !vcpu->evtchn_upcall_mask;
33
34 /* convert to IF type flag
35 -0 -> 0x00000000
36 -1 -> 0xffffffff
37 */
38 return (-flags) & X86_EFLAGS_IF;
39}
40PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl);
41
42static void xen_restore_fl(unsigned long flags)
43{
44 struct vcpu_info *vcpu;
45
46 /* convert from IF type flag */
47 flags = !(flags & X86_EFLAGS_IF);
48
49 /* There's a one instruction preempt window here. We need to
50 make sure we're don't switch CPUs between getting the vcpu
51 pointer and updating the mask. */
52 preempt_disable();
53 vcpu = percpu_read(xen_vcpu);
54 vcpu->evtchn_upcall_mask = flags;
55 preempt_enable_no_resched();
56
57 /* Doesn't matter if we get preempted here, because any
58 pending event will get dealt with anyway. */
59
60 if (flags == 0) {
61 preempt_check_resched();
62 barrier(); /* unmask then check (avoid races) */
63 if (unlikely(vcpu->evtchn_upcall_pending))
64 xen_force_evtchn_callback();
65 }
66}
67PV_CALLEE_SAVE_REGS_THUNK(xen_restore_fl);
68
69static void xen_irq_disable(void)
70{
71 /* There's a one instruction preempt window here. We need to
72 make sure we're don't switch CPUs between getting the vcpu
73 pointer and updating the mask. */
74 preempt_disable();
75 percpu_read(xen_vcpu)->evtchn_upcall_mask = 1;
76 preempt_enable_no_resched();
77}
78PV_CALLEE_SAVE_REGS_THUNK(xen_irq_disable);
79
80static void xen_irq_enable(void)
81{
82 struct vcpu_info *vcpu;
83
84 /* We don't need to worry about being preempted here, since
85 either a) interrupts are disabled, so no preemption, or b)
86 the caller is confused and is trying to re-enable interrupts
87 on an indeterminate processor. */
88
89 vcpu = percpu_read(xen_vcpu);
90 vcpu->evtchn_upcall_mask = 0;
91
92 /* Doesn't matter if we get preempted here, because any
93 pending event will get dealt with anyway. */
94
95 barrier(); /* unmask then check (avoid races) */
96 if (unlikely(vcpu->evtchn_upcall_pending))
97 xen_force_evtchn_callback();
98}
99PV_CALLEE_SAVE_REGS_THUNK(xen_irq_enable);
100
101static void xen_safe_halt(void)
102{
103 /* Blocking includes an implicit local_irq_enable(). */
104 if (HYPERVISOR_sched_op(SCHEDOP_block, NULL) != 0)
105 BUG();
106}
107
108static void xen_halt(void)
109{
110 if (irqs_disabled())
111 HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
112 else
113 xen_safe_halt();
114}
115
116static const struct pv_irq_ops xen_irq_ops __initconst = {
117 .save_fl = PV_CALLEE_SAVE(xen_save_fl),
118 .restore_fl = PV_CALLEE_SAVE(xen_restore_fl),
119 .irq_disable = PV_CALLEE_SAVE(xen_irq_disable),
120 .irq_enable = PV_CALLEE_SAVE(xen_irq_enable),
121
122 .safe_halt = xen_safe_halt,
123 .halt = xen_halt,
124#ifdef CONFIG_X86_64
125 .adjust_exception_frame = xen_adjust_exception_frame,
126#endif
127};
128
129void __init xen_init_irq_ops(void)
130{
131 pv_irq_ops = xen_irq_ops;
132 x86_init.irqs.intr_init = xen_init_IRQ;
133}