linux-stable/include/linux/entry-kvm.h
Peter Zijlstra 26baa1f1c4 sched: Add TIF_NEED_RESCHED_LAZY infrastructure
Add the basic infrastructure to split the TIF_NEED_RESCHED bit in two.
Either bit will cause a resched on return-to-user, but only
TIF_NEED_RESCHED will drive IRQ preemption.

No behavioural change intended.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20241007075055.219540785@infradead.org
2024-11-05 12:55:37 +01:00

101 lines
2.8 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_ENTRYKVM_H
#define __LINUX_ENTRYKVM_H
#include <linux/static_call_types.h>
#include <linux/resume_user_mode.h>
#include <linux/syscalls.h>
#include <linux/seccomp.h>
#include <linux/sched.h>
#include <linux/tick.h>
/* Transfer to guest mode work */
#ifdef CONFIG_KVM_XFER_TO_GUEST_WORK
#ifndef ARCH_XFER_TO_GUEST_MODE_WORK
# define ARCH_XFER_TO_GUEST_MODE_WORK (0)
#endif
#define XFER_TO_GUEST_MODE_WORK \
(_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY | _TIF_SIGPENDING | \
_TIF_NOTIFY_SIGNAL | _TIF_NOTIFY_RESUME | \
ARCH_XFER_TO_GUEST_MODE_WORK)
struct kvm_vcpu;
/**
* arch_xfer_to_guest_mode_handle_work - Architecture specific xfer to guest
* mode work handling function.
* @vcpu: Pointer to current's VCPU data
* @ti_work: Cached TIF flags gathered in xfer_to_guest_mode_handle_work()
*
* Invoked from xfer_to_guest_mode_handle_work(). Defaults to NOOP. Can be
* replaced by architecture specific code.
*/
static inline int arch_xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu,
unsigned long ti_work);
#ifndef arch_xfer_to_guest_mode_work
static inline int arch_xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu,
unsigned long ti_work)
{
return 0;
}
#endif
/**
* xfer_to_guest_mode_handle_work - Check and handle pending work which needs
* to be handled before going to guest mode
* @vcpu: Pointer to current's VCPU data
*
* Returns: 0 or an error code
*/
int xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu);
/**
* xfer_to_guest_mode_prepare - Perform last minute preparation work that
* need to be handled while IRQs are disabled
* upon entering to guest.
*
* Has to be invoked with interrupts disabled before the last call
* to xfer_to_guest_mode_work_pending().
*/
static inline void xfer_to_guest_mode_prepare(void)
{
lockdep_assert_irqs_disabled();
tick_nohz_user_enter_prepare();
}
/**
* __xfer_to_guest_mode_work_pending - Check if work is pending
*
* Returns: True if work pending, False otherwise.
*
* Bare variant of xfer_to_guest_mode_work_pending(). Can be called from
* interrupt enabled code for racy quick checks with care.
*/
static inline bool __xfer_to_guest_mode_work_pending(void)
{
unsigned long ti_work = read_thread_flags();
return !!(ti_work & XFER_TO_GUEST_MODE_WORK);
}
/**
* xfer_to_guest_mode_work_pending - Check if work is pending which needs to be
* handled before returning to guest mode
*
* Returns: True if work pending, False otherwise.
*
* Has to be invoked with interrupts disabled before the transition to
* guest mode.
*/
static inline bool xfer_to_guest_mode_work_pending(void)
{
lockdep_assert_irqs_disabled();
return __xfer_to_guest_mode_work_pending();
}
#endif /* CONFIG_KVM_XFER_TO_GUEST_WORK */
#endif