From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2CF1C433FE for ; Wed, 3 Nov 2021 09:32:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DDAE56052B for ; Wed, 3 Nov 2021 09:32:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231557AbhKCJet (ORCPT ); Wed, 3 Nov 2021 05:34:49 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:46679 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231906AbhKCJeq (ORCPT ); Wed, 3 Nov 2021 05:34:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1635931930; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HXwpnkGi8E1tecrDeHdASgGseLR/pV5+X21g3UrIJX0=; b=CNP4Kxsy2XFaeCohXZeLAjZy9to+Qj+URSrN6sCySX4BPYZrN1Qha6+r59EVFOgsASLQpD g0lNlionHWKsme1XBpVM1+29vEk1X269Zw5cv5My30wp4rTP6bdBrcown+x2gspPiT/h0V e65GTNrZEnlCPI+/BcoLlOd+tUlUXio= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-447-61hBb0CdPaa9GQe4Bh2JFw-1; Wed, 03 Nov 2021 05:32:07 -0400 X-MC-Unique: 61hBb0CdPaa9GQe4Bh2JFw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B896DBBEF7; Wed, 3 Nov 2021 09:32:00 +0000 (UTC) Received: from starship (unknown [10.40.194.243]) by smtp.corp.redhat.com (Postfix) with ESMTP id DE9BD19723; Wed, 3 Nov 2021 09:31:56 +0000 (UTC) Message-ID: Subject: Re: [PATCH] KVM: x86: inhibit APICv when KVM_GUESTDBG_BLOCKIRQ active From: Maxim Levitsky To: kvm@vger.kernel.org Cc: Thomas Gleixner , linux-kernel@vger.kernel.org, Paolo Bonzini , Sean Christopherson , Joerg Roedel , Vitaly Kuznetsov , Borislav Petkov , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , "H. Peter Anvin" , Ingo Molnar , Jim Mattson , Wanpeng Li Date: Wed, 03 Nov 2021 11:31:55 +0200 In-Reply-To: <20211103092912.425128-1-mlevitsk@redhat.com> References: <20211103092912.425128-1-mlevitsk@redhat.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.5 (3.36.5-2.fc32) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, 2021-11-03 at 11:29 +0200, Maxim Levitsky wrote: > KVM_GUESTDBG_BLOCKIRQ relies on interrupts being injected using > standard kvm's inject_pending_event, and not via APICv/AVIC. > > Since this is a debug feature, just inhibit it while it > is in use. > > Signed-off-by: Maxim Levitsky > --- > arch/x86/include/asm/kvm_host.h | 1 + > arch/x86/kvm/svm/avic.c | 3 ++- > arch/x86/kvm/vmx/vmx.c | 3 ++- > arch/x86/kvm/x86.c | 3 +++ > 4 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 88fce6ab4bbd7..8f6e15b95a4d8 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -1034,6 +1034,7 @@ struct kvm_x86_msr_filter { > #define APICV_INHIBIT_REASON_IRQWIN 3 > #define APICV_INHIBIT_REASON_PIT_REINJ 4 > #define APICV_INHIBIT_REASON_X2APIC 5 > +#define APICV_INHIBIT_REASON_BLOCKIRQ 6 > > struct kvm_arch { > unsigned long n_used_mmu_pages; > diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c > index 8052d92069e01..affc0ea98d302 100644 > --- a/arch/x86/kvm/svm/avic.c > +++ b/arch/x86/kvm/svm/avic.c > @@ -904,7 +904,8 @@ bool svm_check_apicv_inhibit_reasons(ulong bit) > BIT(APICV_INHIBIT_REASON_NESTED) | > BIT(APICV_INHIBIT_REASON_IRQWIN) | > BIT(APICV_INHIBIT_REASON_PIT_REINJ) | > - BIT(APICV_INHIBIT_REASON_X2APIC); > + BIT(APICV_INHIBIT_REASON_X2APIC) | > + BIT(APICV_INHIBIT_REASON_BLOCKIRQ); > > return supported & BIT(bit); > } > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 71f54d85f104c..e4fc9ff7cd944 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -7565,7 +7565,8 @@ static void hardware_unsetup(void) > static bool vmx_check_apicv_inhibit_reasons(ulong bit) > { > ulong supported = BIT(APICV_INHIBIT_REASON_DISABLE) | > - BIT(APICV_INHIBIT_REASON_HYPERV); > + BIT(APICV_INHIBIT_REASON_HYPERV) | > + BIT(APICV_INHIBIT_REASON_BLOCKIRQ); > > return supported & BIT(bit); > } > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index ac83d873d65b0..eb3b8d2375713 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -10747,6 +10747,9 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, > if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) > vcpu->arch.singlestep_rip = kvm_get_linear_rip(vcpu); > > + kvm_request_apicv_update(vcpu->kvm, > + !(vcpu->guest_debug & KVM_GUESTDBG_BLOCKIRQ), > + APICV_INHIBIT_REASON_BLOCKIRQ); I need more coffee, bad indention here :) Could you test if this patch works for you? I managed to reproduce this issue on AVIC, by patching out the x2apic inhibit, and then this patch fixed the issue for me. Best regards, Maxim Levitsky > /* > * Trigger an rflags update that will inject or remove the trace > * flags.