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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
55 lines
1.3 KiB
C
55 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/entry-kvm.h>
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#include <linux/kvm_host.h>
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static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work)
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{
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do {
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int ret;
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if (ti_work & _TIF_NOTIFY_SIGNAL)
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tracehook_notify_signal();
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if (ti_work & _TIF_SIGPENDING) {
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kvm_handle_signal_exit(vcpu);
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return -EINTR;
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}
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if (ti_work & _TIF_NEED_RESCHED)
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schedule();
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if (ti_work & _TIF_NOTIFY_RESUME) {
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clear_thread_flag(TIF_NOTIFY_RESUME);
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tracehook_notify_resume(NULL);
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}
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ret = arch_xfer_to_guest_mode_handle_work(vcpu, ti_work);
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if (ret)
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return ret;
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ti_work = READ_ONCE(current_thread_info()->flags);
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} while (ti_work & XFER_TO_GUEST_MODE_WORK || need_resched());
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return 0;
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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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unsigned long ti_work;
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/*
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* This is invoked from the outer guest loop with interrupts and
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* preemption enabled.
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*
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* KVM invokes xfer_to_guest_mode_work_pending() with interrupts
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* disabled in the inner loop before going into guest mode. No need
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* to disable interrupts here.
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*/
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ti_work = READ_ONCE(current_thread_info()->flags);
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if (!(ti_work & XFER_TO_GUEST_MODE_WORK))
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return 0;
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return xfer_to_guest_mode_work(vcpu, ti_work);
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}
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EXPORT_SYMBOL_GPL(xfer_to_guest_mode_handle_work);
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