lkml.org 
[lkml]   [2020]   [May]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: [patch V4 part 1 12/36] x86/kvm: Sanitize kvm_async_pf_task_wait()
    Date
    "Paul E. McKenney" <paulmck@kernel.org> writes:
    > On Tue, May 05, 2020 at 03:16:14PM +0200, Thomas Gleixner wrote:
    >> RCU is watching for:
    >>
    >> #1 The vCPU exited and current is definitely not the idle task
    >>
    >> #2a The #PF entry code on the guest went through enter_from_user_mode()
    >> which reactivates RCU
    >
    > I have to double-check... The NO_HZ_FULL case transitioning to/from
    > userspace is entirely non-preemptible, correct? (After rcu_user_enter()
    > and before rcu_user_exit(), respectively.)

    Yes. It runs with interrupts disabled down to the actual return (sysret,
    iret).

    Thanks,

    tglx


    \
     
     \ /
      Last update: 2020-05-05 23:52    [W:3.721 / U:0.248 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site