From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753975AbbKBL5W (ORCPT ); Mon, 2 Nov 2015 06:57:22 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48339 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753057AbbKBL5S (ORCPT ); Mon, 2 Nov 2015 06:57:18 -0500 Subject: Re: [PATCH] KVM: x86: zero apic_arb_prio on reset To: =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , linux-kernel@vger.kernel.org References: <1446216500-14267-1-git-send-email-rkrcmar@redhat.com> Cc: kvm@vger.kernel.org, Yuki Shibuya From: Paolo Bonzini Message-ID: <56374F98.4050502@redhat.com> Date: Mon, 2 Nov 2015 12:57:12 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <1446216500-14267-1-git-send-email-rkrcmar@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30/10/2015 15:48, Radim Krčmář wrote: > BSP doesn't get INIT so its apic_arb_prio isn't zeroed after reboot. > BSP won't get lowest priority interrupts until other VCPUs get enough > interrupts to match their pre-reboot apic_arb_prio. > > That behavior doesn't fit into KVM's round-robin-like interpretation of > lowest priority delivery ... userspace should KVM_SET_LAPIC on reset, so > just zero apic_arb_prio there. > > Reported-by: Yuki Shibuya > Signed-off-by: Radim Krčmář > --- > arch/x86/kvm/lapic.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > index 1b02c44c7b8b..08655020417d 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -1924,6 +1924,8 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu, > kvm_make_request(KVM_REQ_EVENT, vcpu); > if (ioapic_in_kernel(vcpu->kvm)) > kvm_rtc_eoi_tracking_restore_one(vcpu); > + > + vcpu->arch.apic_arb_prio = 0; > } > > void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu) > Applied, thanks. Paolo