From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751740AbdJMUbP (ORCPT ); Fri, 13 Oct 2017 16:31:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55178 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750973AbdJMUbO (ORCPT ); Fri, 13 Oct 2017 16:31:14 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com F0E4D25784 Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=rkrcmar@redhat.com Date: Fri, 13 Oct 2017 22:31:11 +0200 From: Radim =?utf-8?B?S3LEjW3DocWZ?= To: Wanpeng Li Cc: "linux-kernel@vger.kernel.org" , kvm , Paolo Bonzini , Wanpeng Li Subject: Re: [PATCH v2 4/4] KVM: LAPIC: Don't silently accept bad vectors Message-ID: <20171013203110.GA30745@flask> References: <1506647099-2688-1-git-send-email-wanpeng.li@hotmail.com> <1506647099-2688-5-git-send-email-wanpeng.li@hotmail.com> <20171003175341.GD21107@flask> <20171004120146.GC20277@flask> <20171004144444.GI21107@flask> <20171013173620.GB16116@flask> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20171013173620.GB16116@flask> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 13 Oct 2017 20:31:14 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2017-10-13 19:36+0200, Radim Krčmář: > 2017-10-13 09:17+0800, Wanpeng Li: > > 2017-10-04 22:44 GMT+08:00 Radim Krčmář : > > > 2017-10-04 22:16+0800, Wanpeng Li: > > >> 2017-10-04 20:01 GMT+08:00 Radim Krčmář : > > >> > 2017-10-04 15:56+0800, Wanpeng Li: > > >> >> 2017-10-04 1:53 GMT+08:00 Radim Krčmář : > > >> >> > 2017-09-28 18:04-0700, Wanpeng Li: > > >> >> >> @@ -946,6 +965,11 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode, > > >> >> >> int result = 0; > > >> >> >> struct kvm_vcpu *vcpu = apic->vcpu; > > >> >> >> > > >> >> >> + if (unlikely(vector < 16) && delivery_mode == APIC_DM_FIXED) { > > >> >> >> + apic_error(apic, APIC_ESR_RECVILL); > > >> >> > > > >> >> > The error is also triggered if lowest priority is supported and tries to > > >> >> > deliver an invalid vector. > > >> >> > > >> >> Could you point out this in SDM? :) > > >> > > > >> > In section 10.5.3 Error Handling: > > >> > > > >> > If the local APIC does not support the sending of lowest-priority IPIs > > >> > and software writes the ICR to send a lowest-priority IPI with an > > >> > illegal vector, the local APIC sets only the “redirectible IPI” error > > >> > bit. > > >> > > > >> > Hence, if local APIC does support lowest-priority, then it throws the > > >> > same error as fixed. (KVM does support lowest-priority.) > > >> > > >> Yeah, I read the section before but I misunderstand it. It seems that > > >> the section means it just occurs when the local APIC does not support > > >> the sending of lowest-priority IPIs? > > > > > > I think so. > > > > I see Virtualbox just captures Fixed delivery mode for error handling. > > Hm, it doesn't even inject an error on destination of the > lowest-priority interrupt and just drop it? > > I can't interpret the SDM in any other way, though: > > When an interrupt vector in the range of 0 to 15 is sent or received > through the local APIC, the APIC indicates an illegal vector in its > Error Status Register (see Section 10.5.3, “Error Handling”). > > and we support lowest-priority interrupts, because if we didn't, then > > The interrupt is not processed and hence the “Send Illegal Vector” bit > is not set in the ESR. > > I'll go for a quick bare-metal test ... Turns out my machine doesn't support for lowest priority IPIs (probably got killed with FSB), so all I get is error 0x10.