linux/arch/x86/xen/irq.c
Juergen Gross 5c83511bdb x86/paravirt: Use a single ops structure
Instead of using six globally visible paravirt ops structures combine
them in a single structure, keeping the original structures as
sub-structures.

This avoids the need to assemble struct paravirt_patch_template at
runtime on the stack each time apply_paravirt() is being called (i.e.
when loading a module).

[ tglx: Made the struct and the initializer tabular for readability sake ]

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: akataria@vmware.com
Cc: rusty@rustcorp.com.au
Cc: boris.ostrovsky@oracle.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20180828074026.820-9-jgross@suse.com
2018-09-03 16:50:35 +02:00

134 lines
3.2 KiB
C

// 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_ops.irq = xen_irq_ops;
x86_init.irqs.intr_init = xen_init_IRQ;
}