forked from mirrors/linux
6ce895128b
Some thread flags can be set remotely, and so even when IRQs are disabled, the flags can change under our feet. Generally this is unlikely to cause a problem in practice, but it is somewhat unsound, and KCSAN will legitimately warn that there is a data race. To avoid such issues, a snapshot of the flags has to be taken prior to using them. Some places already use READ_ONCE() for that, others do not. Convert them all to the new flag accessor helpers. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/r/20211129130653.2037928-3-mark.rutland@arm.com
99 lines
2.7 KiB
C
99 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_ENTRYKVM_H
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#define __LINUX_ENTRYKVM_H
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#include <linux/static_call_types.h>
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#include <linux/tracehook.h>
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#include <linux/syscalls.h>
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#include <linux/seccomp.h>
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#include <linux/sched.h>
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#include <linux/tick.h>
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/* Transfer to guest mode work */
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#ifdef CONFIG_KVM_XFER_TO_GUEST_WORK
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#ifndef ARCH_XFER_TO_GUEST_MODE_WORK
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# define ARCH_XFER_TO_GUEST_MODE_WORK (0)
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#endif
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#define XFER_TO_GUEST_MODE_WORK \
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(_TIF_NEED_RESCHED | _TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL | \
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_TIF_NOTIFY_RESUME | ARCH_XFER_TO_GUEST_MODE_WORK)
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struct kvm_vcpu;
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/**
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* arch_xfer_to_guest_mode_handle_work - Architecture specific xfer to guest
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* mode work handling function.
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* @vcpu: Pointer to current's VCPU data
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* @ti_work: Cached TIF flags gathered in xfer_to_guest_mode_handle_work()
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*
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* Invoked from xfer_to_guest_mode_handle_work(). Defaults to NOOP. Can be
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* replaced by architecture specific code.
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*/
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static inline int arch_xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu,
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unsigned long ti_work);
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#ifndef arch_xfer_to_guest_mode_work
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static inline int arch_xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu,
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unsigned long ti_work)
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{
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return 0;
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}
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#endif
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/**
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* xfer_to_guest_mode_handle_work - Check and handle pending work which needs
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* to be handled before going to guest mode
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* @vcpu: Pointer to current's VCPU data
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*
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* Returns: 0 or an error code
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*/
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int xfer_to_guest_mode_handle_work(struct kvm_vcpu *vcpu);
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/**
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* xfer_to_guest_mode_prepare - Perform last minute preparation work that
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* need to be handled while IRQs are disabled
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* upon entering to guest.
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*
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* Has to be invoked with interrupts disabled before the last call
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* to xfer_to_guest_mode_work_pending().
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*/
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static inline void xfer_to_guest_mode_prepare(void)
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{
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lockdep_assert_irqs_disabled();
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tick_nohz_user_enter_prepare();
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}
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/**
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* __xfer_to_guest_mode_work_pending - Check if work is pending
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*
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* Returns: True if work pending, False otherwise.
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*
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* Bare variant of xfer_to_guest_mode_work_pending(). Can be called from
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* interrupt enabled code for racy quick checks with care.
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*/
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static inline bool __xfer_to_guest_mode_work_pending(void)
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{
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unsigned long ti_work = read_thread_flags();
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return !!(ti_work & XFER_TO_GUEST_MODE_WORK);
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}
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/**
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* xfer_to_guest_mode_work_pending - Check if work is pending which needs to be
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* handled before returning to guest mode
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*
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* Returns: True if work pending, False otherwise.
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*
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* Has to be invoked with interrupts disabled before the transition to
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* guest mode.
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*/
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static inline bool xfer_to_guest_mode_work_pending(void)
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{
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lockdep_assert_irqs_disabled();
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return __xfer_to_guest_mode_work_pending();
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}
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#endif /* CONFIG_KVM_XFER_TO_GUEST_WORK */
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#endif
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