From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Hildenbrand Subject: Re: [PATCH v3 03/24] KVM: x86: check against irqchip_mode in kvm_set_routing_entry() Date: Wed, 12 Apr 2017 21:56:43 +0200 Message-ID: References: <20170407085041.5257-1-david@redhat.com> <20170407085041.5257-4-david@redhat.com> <20170412183655.GB20145@potion> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: kvm@vger.kernel.org, Paolo Bonzini , Peter Xu To: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= Return-path: Received: from mx1.redhat.com ([209.132.183.28]:37642 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754634AbdDLT4s (ORCPT ); Wed, 12 Apr 2017 15:56:48 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9DAFF80488 for ; Wed, 12 Apr 2017 19:56:47 +0000 (UTC) In-Reply-To: <20170412183655.GB20145@potion> Sender: kvm-owner@vger.kernel.org List-ID: On 12.04.2017 20:36, Radim Krčmář wrote: > 2017-04-07 10:50+0200, David Hildenbrand: >> Let's replace the checks for pic_in_kernel() and ioapic_in_kernel() by >> checks against irqchip_mode. >> >> Also make sure that creation of any route is only possible if we have >> an lapic in kernel (irqchip_in_kernel()) or if we are currently >> inititalizing the irqchip. >> >> This is necessary to switch pic_in_kernel() and ioapic_in_kernel() to >> irqchip_mode, too. >> >> Signed-off-by: David Hildenbrand >> --- >> arch/x86/kvm/irq_comm.c | 14 ++++++++------ >> 1 file changed, 8 insertions(+), 6 deletions(-) >> >> diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c >> index 6825cd3..2e5eec8 100644 >> --- a/arch/x86/kvm/irq_comm.c >> +++ b/arch/x86/kvm/irq_comm.c >> @@ -282,24 +282,26 @@ int kvm_set_routing_entry(struct kvm *kvm, >> int delta; >> unsigned max_pin; >> >> + /* also allow creation of routes during KVM_IRQCHIP_INIT_IN_PROGRESS */ >> + if (kvm->arch.irqchip_mode == KVM_IRQCHIP_NONE) >> + goto out; >> + >> + /* Matches smp_wmb() when setting irqchip_mode */ >> + smp_rmb(); > > This barrier is superfluous as well ... aren't all callers using > kvm->lock to provide ordering? Yes they are. Paolo suggested this. I think we can safely drop this. Thanks! > > The check for KVM_IRQCHIP_NONE would prevent nothing if we could catch > the initialization from the outside and hence need a barrier. > > Thanks. > -- Thanks, David