From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sean Christopherson Subject: Re: [patch V5 15/15] x86/kvm: Use generic xfer to guest work function Date: Thu, 23 Jul 2020 17:17:36 -0700 Message-ID: <20200724001736.GK21891@linux.intel.com> References: <20200722215954.464281930@linutronix.de> <20200722220520.979724969@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mga14.intel.com ([192.55.52.115]:40353 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728285AbgGXARh (ORCPT ); Thu, 23 Jul 2020 20:17:37 -0400 Content-Disposition: inline In-Reply-To: <20200722220520.979724969@linutronix.de> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Thomas Gleixner Cc: LKML , x86@kernel.org, linux-arch@vger.kernel.org, Will Deacon , Arnd Bergmann , Mark Rutland , Kees Cook , Keno Fischer , Paolo Bonzini , kvm@vger.kernel.org, Gabriel Krisman Bertazi On Thu, Jul 23, 2020 at 12:00:09AM +0200, Thomas Gleixner wrote: > From: Thomas Gleixner > > Use the generic infrastructure to check for and handle pending work before > transitioning into guest mode. > > This now handles TIF_NOTIFY_RESUME as well which was ignored so > far. Handling it is important as this covers task work and task work will > be used to offload the heavy lifting of POSIX CPU timers to thread context. > > Signed-off-by: Thomas Gleixner > --- > V5: Rename exit -> xfer > --- One nit/question below (though it's really about patch 5). Reviewed-and-tested-by: Sean Christopherson > @@ -8676,15 +8677,11 @@ static int vcpu_run(struct kvm_vcpu *vcp > break; > } > > - if (signal_pending(current)) { > - r = -EINTR; > - vcpu->run->exit_reason = KVM_EXIT_INTR; > - ++vcpu->stat.signal_exits; > - break; > - } > - if (need_resched()) { > + if (xfer_to_guest_mode_work_pending()) { > srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx); > - cond_resched(); > + r = xfer_to_guest_mode(vcpu); Any reason not to call this xfer_to_guest_mode_work()? Or handle_work(), do_work(), etc... Without the "work" part, it looks like a function that should be invoked unconditionally. It's obvious that's not the case if one looks at the implementation, but it's a bit confusing on the KVM side of things. > + if (r) > + return r; > vcpu->srcu_idx = srcu_read_lock(&kvm->srcu); > } > } >