// SPDX-License-Identifier: GPL-2.0
|
#include <linux/hardirq.h>
|
|
#include <asm/x86_init.h>
|
|
#include <xen/interface/xen.h>
|
#include <xen/interface/sched.h>
|
#include <xen/interface/vcpu.h>
|
#include <xen/features.h>
|
#include <xen/events.h>
|
|
#include <asm/xen/hypercall.h>
|
#include <asm/xen/hypervisor.h>
|
|
#include "xen-ops.h"
|
|
/*
|
* Force a proper event-channel callback from Xen after clearing the
|
* callback mask. We do this in a very simple manner, by making a call
|
* down into Xen. The pending flag will be checked by Xen on return.
|
*/
|
void xen_force_evtchn_callback(void)
|
{
|
(void)HYPERVISOR_xen_version(0, NULL);
|
}
|
|
asmlinkage __visible unsigned long xen_save_fl(void)
|
{
|
struct vcpu_info *vcpu;
|
unsigned long flags;
|
|
vcpu = this_cpu_read(xen_vcpu);
|
|
/* flag has opposite sense of mask */
|
flags = !vcpu->evtchn_upcall_mask;
|
|
/* convert to IF type flag
|
-0 -> 0x00000000
|
-1 -> 0xffffffff
|
*/
|
return (-flags) & X86_EFLAGS_IF;
|
}
|
PV_CALLEE_SAVE_REGS_THUNK(xen_save_fl);
|
|
__visible void xen_restore_fl(unsigned long flags)
|
{
|
struct vcpu_info *vcpu;
|
|
/* convert from IF type flag */
|
flags = !(flags & X86_EFLAGS_IF);
|
|
/* See xen_irq_enable() for why preemption must be disabled. */
|
preempt_disable();
|
vcpu = this_cpu_read(xen_vcpu);
|
vcpu->evtchn_upcall_mask = flags;
|
|
if (flags == 0) {
|
barrier(); /* unmask then check (avoid races) */
|
if (unlikely(vcpu->evtchn_upcall_pending))
|
xen_force_evtchn_callback();
|
preempt_enable();
|
} else
|
preempt_enable_no_resched();
|
}
|
PV_CALLEE_SAVE_REGS_THUNK(xen_restore_fl);
|
|
asmlinkage __visible void xen_irq_disable(void)
|
{
|
/* There's a one instruction preempt window here. We need to
|
make sure we're don't switch CPUs between getting the vcpu
|
pointer and updating the mask. */
|
preempt_disable();
|
this_cpu_read(xen_vcpu)->evtchn_upcall_mask = 1;
|
preempt_enable_no_resched();
|
}
|
PV_CALLEE_SAVE_REGS_THUNK(xen_irq_disable);
|
|
asmlinkage __visible void xen_irq_enable(void)
|
{
|
struct vcpu_info *vcpu;
|
|
/*
|
* We may be preempted as soon as vcpu->evtchn_upcall_mask is
|
* cleared, so disable preemption to ensure we check for
|
* events on the VCPU we are still running on.
|
*/
|
preempt_disable();
|
|
vcpu = this_cpu_read(xen_vcpu);
|
vcpu->evtchn_upcall_mask = 0;
|
|
/* Doesn't matter if we get preempted here, because any
|
pending event will get dealt with anyway. */
|
|
barrier(); /* unmask then check (avoid races) */
|
if (unlikely(vcpu->evtchn_upcall_pending))
|
xen_force_evtchn_callback();
|
|
preempt_enable();
|
}
|
PV_CALLEE_SAVE_REGS_THUNK(xen_irq_enable);
|
|
static void xen_safe_halt(void)
|
{
|
/* Blocking includes an implicit local_irq_enable(). */
|
if (HYPERVISOR_sched_op(SCHEDOP_block, NULL) != 0)
|
BUG();
|
}
|
|
static void xen_halt(void)
|
{
|
if (irqs_disabled())
|
HYPERVISOR_vcpu_op(VCPUOP_down,
|
xen_vcpu_nr(smp_processor_id()), NULL);
|
else
|
xen_safe_halt();
|
}
|
|
static const struct pv_irq_ops xen_irq_ops __initconst = {
|
.save_fl = PV_CALLEE_SAVE(xen_save_fl),
|
.restore_fl = PV_CALLEE_SAVE(xen_restore_fl),
|
.irq_disable = PV_CALLEE_SAVE(xen_irq_disable),
|
.irq_enable = PV_CALLEE_SAVE(xen_irq_enable),
|
|
.safe_halt = xen_safe_halt,
|
.halt = xen_halt,
|
};
|
|
void __init xen_init_irq_ops(void)
|
{
|
pv_irq_ops = xen_irq_ops;
|
x86_init.irqs.intr_init = xen_init_IRQ;
|
}
|
