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 */
22noinstr void xen_force_evtchn_callback(void)
23{
24	(void)HYPERVISOR_xen_version(0, NULL);
25}
26
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
27static void xen_safe_halt(void)
28{
29	/* Blocking includes an implicit local_irq_enable(). */
30	if (HYPERVISOR_sched_op(SCHEDOP_block, NULL) != 0)
31		BUG();
32}
33
34static void xen_halt(void)
35{
36	if (irqs_disabled())
37		HYPERVISOR_vcpu_op(VCPUOP_down,
38				   xen_vcpu_nr(smp_processor_id()), NULL);
39	else
40		xen_safe_halt();
41}
42
43static const typeof(pv_ops) xen_irq_ops __initconst = {
44	.irq = {
45		/* Initial interrupt flag handling only called while interrupts off. */
46		.save_fl = __PV_IS_CALLEE_SAVE(paravirt_ret0),
47		.irq_disable = __PV_IS_CALLEE_SAVE(paravirt_nop),
48		.irq_enable = __PV_IS_CALLEE_SAVE(paravirt_BUG),
49
50		.safe_halt = xen_safe_halt,
51		.halt = xen_halt,
52	},
 
53};
54
55void __init xen_init_irq_ops(void)
56{
57	pv_ops.irq = xen_irq_ops.irq;
 
 
58	x86_init.irqs.intr_init = xen_init_IRQ;
59}