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7c5d8fa6fb
There are a small handful of reasons besides pending signals that the kernel might want to break out of interruptible sleeps. The flag TIF_NOTIFY_SIGNAL and the helpers that set and clear TIF_NOTIFY_SIGNAL provide that the infrastructure for breaking out of interruptible sleeps and entering the return to user space slow path for those cases. Expand tracehook_notify_signal inline in it's callers and remove it, which makes clear that TIF_NOTIFY_SIGNAL and task_work are separate concepts. Update the comment on set_notify_signal to more accurately describe it's purpose. Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lkml.kernel.org/r/20220309162454.123006-9-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
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clear_notify_signal();
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if (task_work_pending(current))
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task_work_run();
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}
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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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tracehook_notify_resume(NULL);
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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_thread_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_thread_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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