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    SubjectRe: [RFC patch 14/15] workpending: Provide infrastructure for work before entering a guest
    > --- a/include/linux/entry-common.h
    > +++ b/include/linux/entry-common.h

    [...]

    > +#define EXIT_TO_GUESTMODE_WORK \
    > + (_TIF_NEED_RESCHED | _TIF_SIGPENDING | _TIF_NOTIFY_RESUME | \
    > + ARCH_EXIT_TO_GUESTMODE_WORK)

    [...]

    > --- a/kernel/entry/common.c
    > +++ b/kernel/entry/common.c
    >
    > +int core_exit_to_guestmode_work(struct kvm *kvm, struct kvm_vcpu *vcpu,
    > + unsigned long ti_work)
    > +{
    > + /*
    > + * Before returning to guest mode handle all pending work
    > + */
    > + if (ti_work & _TIF_SIGPENDING) {
    > + vcpu->run->exit_reason = KVM_EXIT_INTR;
    > + vcpu->stat.signal_exits++;
    > + return -EINTR;
    > + }
    > +
    > + if (ti_work & _TIF_NEED_RESCHED) {
    > + srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
    > + schedule();
    > + vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
    > + }
    > +
    > + if (ti_work & _TIF_PATCH_PENDING) {
    > + srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
    > + klp_update_patch_state(current);
    > + vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
    > + }

    If I am reading the code correctly, _TIF_PATCH_PENDING is not a part of
    EXIT_TO_GUESTMODE_WORK, so the handling code here would not be called on
    any arch as of now.

    I also think that _TIF_PATCH_PENDING must not be handled here generally.
    It could break consistency guarantees when live patching KVM (and we do
    that from time to time).

    Adding live-patching ML to CC.

    Miroslav

    > + if (ti_work & _TIF_NOTIFY_RESUME) {
    > + srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
    > + clear_thread_flag(TIF_NOTIFY_RESUME);
    > + tracehook_notify_resume(NULL);
    > + vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
    > + }
    > +
    > + /* Any extra architecture specific work */
    > + return arch_exit_to_guestmode_work(kvm, vcpu, ti_work);
    > +}

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