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4ae7dc97f7
Following the idle loop model, cleanly check for pending rcuog wakeup before the last rescheduling point upon resuming to guest mode. This way we can avoid to do it from rcu_user_enter() with the last resort self-IPI hack that enforces rescheduling. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20210131230548.32970-6-frederic@kernel.org
94 lines
2.6 KiB
C
94 lines
2.6 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/entry-common.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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rcu_nocb_flush_deferred_wakeup();
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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_ONCE(current_thread_info()->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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