On Wed, Oct 09, 2013 at 11:26:58PM +0200, Paolo Bonzini wrote:
> Il 09/10/2013 21:41, Marcelo Tosatti ha scritto:
> >> > How was that tested? For BUS_MCEERR_AO it can work, but BUS_MCEERR_AR
> >> > calls force_sig_info which does this:
> >> >
> >> > ignored = action->sa.sa_handler == SIG_IGN;
> >> > blocked = sigismember(&t->blocked, sig);
> >> > if (blocked || ignored) {
> >> > action->sa.sa_handler = SIG_DFL;
> >> > if (blocked) {
> >> > sigdelset(&t->blocked, sig);
> >> > recalc_sigpending_and_wake(t);
> >> > }
> >> >
> >> > if (action->sa.sa_handler == SIG_DFL)
> >> > t->signal->flags &= ~SIGNAL_UNKILLABLE;
> >> >
> >> > and kills the process (because that's the default action of SIG_DFL).
> > For vcpu context its not blocked?
>
> It causes KVM to exit back to userspace, but as soon as KVM exits it
> should be blocked. Thus a SIGBUS with BUS_MCEERR_AR will never be
> returned by sigtimedwait.
Its blocked but readable via signalfd.
Its generated when vcpu touches memory, see 77db5cbd29b7cb0e0fb4fd14.
Since its rarely used, reviewing the code is not a bad idea.
For the test, see
https://lists.nongnu.org/archive/html/qemu-devel/2011-01/msg01588.html.
