From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yang Zhang Subject: Re: [PATCH v3 1/4] KVM: Recover IRTE to remapped mode if the interrupt is not single-destination Date: Thu, 21 Jan 2016 11:05:46 +0800 Message-ID: <56A04B0A.2020505@gmail.com> References: <1453254177-103002-1-git-send-email-feng.wu@intel.com> <1453254177-103002-2-git-send-email-feng.wu@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org To: Feng Wu , pbonzini@redhat.com, rkrcmar@redhat.com Return-path: Received: from mail-pf0-f193.google.com ([209.85.192.193]:35738 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751060AbcAUDFy (ORCPT ); Wed, 20 Jan 2016 22:05:54 -0500 In-Reply-To: <1453254177-103002-2-git-send-email-feng.wu@intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On 2016/1/20 9:42, Feng Wu wrote: > When the interrupt is not single destination any more, we need > to change back IRTE to remapped mode explicitly. > > Signed-off-by: Feng Wu > --- > arch/x86/kvm/vmx.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index e2951b6..13d14d4 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -10764,8 +10764,17 @@ static int vmx_update_pi_irte(struct kvm *kvm, unsigned int host_irq, > */ > > kvm_set_msi_irq(e, &irq); > - if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu)) > + if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu)) { > + /* > + * Make sure the IRTE is in remapped mode if > + * we don't handle it in posted mode. > + */ > + pi_set_sn(vcpu_to_pi_desc(vcpu)); > + ret = irq_set_vcpu_affinity(host_irq, NULL); > + pi_clear_sn(vcpu_to_pi_desc(vcpu)); > + > continue; > + } > > vcpu_info.pi_desc_addr = __pa(vcpu_to_pi_desc(vcpu)); > vcpu_info.vector = irq.vector; > I am still feel weird with this change: according the semantic of VT-d posted interrupt, the interrupt will injected to guest through posted notification and /proc/interrupts shows the same meaning. But now, without being aware of user, the interrupt changes to legacy way and it appears on different entry on /proc/interrupts. It looks weird. Any comments? Paolo. -- best regards yang