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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// SPDX-License-Identifier: GPL-2.0
2#include <linux/hardirq.h>
3
4#include <asm/x86_init.h>
5
6#include <xen/interface/xen.h>
7#include <xen/interface/sched.h>
8#include <xen/interface/vcpu.h>
9#include <xen/features.h>
10#include <xen/events.h>
11
12#include <asm/xen/hypercall.h>
13#include <asm/xen/hypervisor.h>
14
15#include "xen-ops.h"
16
17/*
18 * Force a proper event-channel callback from Xen after clearing the
19 * callback mask. We do this in a very simple manner, by making a call
20 * down into Xen. The pending flag will be checked by Xen on return.
21 */
22void xen_force_evtchn_callback(void)
23{
24 (void)HYPERVISOR_xen_version(0, NULL);
25}
26
27asmlinkage __visible unsigned long xen_save_fl(void)
28{
29 struct vcpu_info *vcpu;
30 unsigned long flags;
31
32 vcpu = this_cpu_read(xen_vcpu);
33
34 /* flag has opposite sense of mask */
35 flags = !vcpu->evtchn_upcall_mask;
36
37 /* convert to IF type flag
38 -0 -> 0x00000000
39 -1 -> 0xffffffff
40 */
41 return (-flags) & X86_EFLAGS_IF;
42}
43PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl);
44
45__visible void xen_restore_fl(unsigned long flags)
46{
47 struct vcpu_info *vcpu;
48
49 /* convert from IF type flag */
50 flags = !(flags & X86_EFLAGS_IF);
51
52 /* See xen_irq_enable() for why preemption must be disabled. */
53 preempt_disable();
54 vcpu = this_cpu_read(xen_vcpu);
55 vcpu->evtchn_upcall_mask = flags;
56
57 if (flags == 0) {
58 barrier(); /* unmask then check (avoid races) */
59 if (unlikely(vcpu->evtchn_upcall_pending))
60 xen_force_evtchn_callback();
61 preempt_enable();
62 } else
63 preempt_enable_no_resched();
64}
65PV_CALLEE_SAVE_REGS_THUNK(xen_restore_fl);
66
67asmlinkage __visible void xen_irq_disable(void)
68{
69 /* There's a one instruction preempt window here. We need to
70 make sure we're don't switch CPUs between getting the vcpu
71 pointer and updating the mask. */
72 preempt_disable();
73 this_cpu_read(xen_vcpu)->evtchn_upcall_mask = 1;
74 preempt_enable_no_resched();
75}
76PV_CALLEE_SAVE_REGS_THUNK(xen_irq_disable);
77
78asmlinkage __visible void xen_irq_enable(void)
79{
80 struct vcpu_info *vcpu;
81
82 /*
83 * We may be preempted as soon as vcpu->evtchn_upcall_mask is
84 * cleared, so disable preemption to ensure we check for
85 * events on the VCPU we are still running on.
86 */
87 preempt_disable();
88
89 vcpu = this_cpu_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
99 preempt_enable();
100}
101PV_CALLEE_SAVE_REGS_THUNK(xen_irq_enable);
102
103static void xen_safe_halt(void)
104{
105 /* Blocking includes an implicit local_irq_enable(). */
106 if (HYPERVISOR_sched_op(SCHEDOP_block, NULL) != 0)
107 BUG();
108}
109
110static void xen_halt(void)
111{
112 if (irqs_disabled())
113 HYPERVISOR_vcpu_op(VCPUOP_down,
114 xen_vcpu_nr(smp_processor_id()), NULL);
115 else
116 xen_safe_halt();
117}
118
119static const struct pv_irq_ops xen_irq_ops __initconst = {
120 .save_fl = PV_CALLEE_SAVE(xen_save_fl),
121 .restore_fl = PV_CALLEE_SAVE(xen_restore_fl),
122 .irq_disable = PV_CALLEE_SAVE(xen_irq_disable),
123 .irq_enable = PV_CALLEE_SAVE(xen_irq_enable),
124
125 .safe_halt = xen_safe_halt,
126 .halt = xen_halt,
127};
128
129void __init xen_init_irq_ops(void)
130{
131 /* For PVH we use default pv_irq_ops settings. */
132 if (!xen_feature(XENFEAT_hvm_callback_vector))
133 pv_irq_ops = xen_irq_ops;
134 x86_init.irqs.intr_init = xen_init_IRQ;
135}