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12db8b6900
Add TIF_NOTIFY_SIGNAL handling in the generic entry code, which if set, will return true if signal_pending() is used in a wait loop. That causes an exit of the loop so that notify_signal tracehooks can be run. If the wait loop is currently inside a system call, the system call is restarted once task_work has been processed. In preparation for only having arch_do_signal() handle syscall restarts if _TIF_SIGPENDING isn't set, rename it to arch_do_signal_or_restart(). Pass in a boolean that tells the architecture specific signal handler if it should attempt to get a signal, or just process a potential syscall restart. For !CONFIG_GENERIC_ENTRY archs, add the TIF_NOTIFY_SIGNAL handling to get_signal(). This is done to minimize the needed architecture changes to support this feature. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Link: https://lore.kernel.org/r/20201026203230.386348-3-axboe@kernel.dk
80 lines
2.2 KiB
C
80 lines
2.2 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_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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