Commit | Line | Data |
---|---|---|
0d1edf46 JF |
1 | #include <linux/hardirq.h> |
2 | ||
66bcaf0b TG |
3 | #include <asm/x86_init.h> |
4 | ||
0d1edf46 JF |
5 | #include <xen/interface/xen.h> |
6 | #include <xen/interface/sched.h> | |
7 | #include <xen/interface/vcpu.h> | |
0ec53ecf | 8 | #include <xen/events.h> |
0d1edf46 JF |
9 | |
10 | #include <asm/xen/hypercall.h> | |
11 | #include <asm/xen/hypervisor.h> | |
12 | ||
13 | #include "xen-ops.h" | |
14 | ||
15 | /* | |
16 | * Force a proper event-channel callback from Xen after clearing the | |
17 | * callback mask. We do this in a very simple manner, by making a call | |
18 | * down into Xen. The pending flag will be checked by Xen on return. | |
19 | */ | |
20 | void xen_force_evtchn_callback(void) | |
21 | { | |
22 | (void)HYPERVISOR_xen_version(0, NULL); | |
23 | } | |
24 | ||
0d1edf46 JF |
25 | static unsigned long xen_save_fl(void) |
26 | { | |
27 | struct vcpu_info *vcpu; | |
28 | unsigned long flags; | |
29 | ||
2113f469 | 30 | vcpu = this_cpu_read(xen_vcpu); |
0d1edf46 JF |
31 | |
32 | /* flag has opposite sense of mask */ | |
33 | flags = !vcpu->evtchn_upcall_mask; | |
34 | ||
35 | /* convert to IF type flag | |
36 | -0 -> 0x00000000 | |
37 | -1 -> 0xffffffff | |
38 | */ | |
39 | return (-flags) & X86_EFLAGS_IF; | |
40 | } | |
ecb93d1c | 41 | PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl); |
0d1edf46 JF |
42 | |
43 | static void xen_restore_fl(unsigned long flags) | |
44 | { | |
45 | struct vcpu_info *vcpu; | |
46 | ||
47 | /* convert from IF type flag */ | |
48 | flags = !(flags & X86_EFLAGS_IF); | |
49 | ||
fb58e300 | 50 | /* See xen_irq_enable() for why preemption must be disabled. */ |
0d1edf46 | 51 | preempt_disable(); |
2113f469 | 52 | vcpu = this_cpu_read(xen_vcpu); |
0d1edf46 | 53 | vcpu->evtchn_upcall_mask = flags; |
0d1edf46 JF |
54 | |
55 | if (flags == 0) { | |
0d1edf46 JF |
56 | barrier(); /* unmask then check (avoid races) */ |
57 | if (unlikely(vcpu->evtchn_upcall_pending)) | |
58 | xen_force_evtchn_callback(); | |
fb58e300 DV |
59 | preempt_enable(); |
60 | } else | |
61 | preempt_enable_no_resched(); | |
0d1edf46 | 62 | } |
ecb93d1c | 63 | PV_CALLEE_SAVE_REGS_THUNK(xen_restore_fl); |
0d1edf46 JF |
64 | |
65 | static void xen_irq_disable(void) | |
66 | { | |
67 | /* There's a one instruction preempt window here. We need to | |
68 | make sure we're don't switch CPUs between getting the vcpu | |
69 | pointer and updating the mask. */ | |
70 | preempt_disable(); | |
2113f469 | 71 | this_cpu_read(xen_vcpu)->evtchn_upcall_mask = 1; |
0d1edf46 JF |
72 | preempt_enable_no_resched(); |
73 | } | |
ecb93d1c | 74 | PV_CALLEE_SAVE_REGS_THUNK(xen_irq_disable); |
0d1edf46 JF |
75 | |
76 | static void xen_irq_enable(void) | |
77 | { | |
78 | struct vcpu_info *vcpu; | |
79 | ||
fb58e300 DV |
80 | /* |
81 | * We may be preempted as soon as vcpu->evtchn_upcall_mask is | |
82 | * cleared, so disable preemption to ensure we check for | |
83 | * events on the VCPU we are still running on. | |
84 | */ | |
85 | preempt_disable(); | |
0d1edf46 | 86 | |
2113f469 | 87 | vcpu = this_cpu_read(xen_vcpu); |
0d1edf46 JF |
88 | vcpu->evtchn_upcall_mask = 0; |
89 | ||
90 | /* Doesn't matter if we get preempted here, because any | |
91 | pending event will get dealt with anyway. */ | |
92 | ||
93 | barrier(); /* unmask then check (avoid races) */ | |
94 | if (unlikely(vcpu->evtchn_upcall_pending)) | |
95 | xen_force_evtchn_callback(); | |
fb58e300 DV |
96 | |
97 | preempt_enable(); | |
0d1edf46 | 98 | } |
ecb93d1c | 99 | PV_CALLEE_SAVE_REGS_THUNK(xen_irq_enable); |
0d1edf46 JF |
100 | |
101 | static 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 | ||
108 | static 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 | ||
251511a1 | 116 | static const struct pv_irq_ops xen_irq_ops __initconst = { |
ecb93d1c JF |
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 | ||
0d1edf46 JF |
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 | ||
7d81c3b9 | 129 | void __init xen_init_irq_ops(void) |
0d1edf46 JF |
130 | { |
131 | pv_irq_ops = xen_irq_ops; | |
66bcaf0b | 132 | x86_init.irqs.intr_init = xen_init_IRQ; |
0d1edf46 | 133 | } |