Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752449AbbB0JWo (ORCPT ); Fri, 27 Feb 2015 04:22:44 -0500 Received: from mga14.intel.com ([192.55.52.115]:49681 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751232AbbB0JWm (ORCPT ); Fri, 27 Feb 2015 04:22:42 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,658,1418112000"; d="scan'208";a="672564563" Date: Fri, 27 Feb 2015 17:04:20 +0800 From: Wanpeng Li To: Wincy Van Cc: Yong Wang , Paolo Bonzini , "gleb@kernel.org" , "Zhang, Yang Z" , Wanpeng Li , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Jan Kiszka , mtosatti@redhat.com, rongrongx.liu@intel.com Subject: Re: [PATCH resend v5 6/6] KVM: nVMX: Enable nested posted interrupt processing Message-ID: <20150227090420.GA22474@kernel> Reply-To: Wanpeng Li References: <1422979097-2203-1-git-send-email-fanwenyi0529@gmail.com> <20150215062755.GA2603@ywang-linux> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2710 Lines: 79 Cc Rongrong, On Fri, Feb 27, 2015 at 04:56:06PM +0800, Wincy Van wrote: >On Sun, Feb 15, 2015 at 2:27 PM, Yong Wang wrote: >> >> Wincy, our QA found regressions with this patch that 64bit L2 linux guest >> fails to boot up when running nested kvm on kvm. >> >> Environment: >> ------------ >> Host OS (ia32/ia32e/IA64):ia32e >> Guest OS (ia32/ia32e/IA64):ia32e >> Guest OS Type (Linux/Windows):Linux >> kvm.git Commit:6557bada461afeaa920a189fae2cff7c8fdce39f >> qemu.kvm Commit:5c697ae74170d43928cb185f5ac1a9058adcae0b >> Host Kernel Version:3.19.0-rc3 >> Hardware:Ivytown_EP, Haswell_EP >> >> >> Bug detailed description: >> -------------------------- >> create 64bit linux guest as L2 guest, the guest boot up fail >> >> note: >> 1. create a 32bit linux guest as L2 guest, the guest boots up fine. >> 2. create a 64bit windows guest as L2 guest, the guest boots up fine. >> 3. this should be a kernel bug: >> kvm + qemu = result >> 6557bada + 5c697ae7 = bad >> 8fff5e37 + 5c697ae7 = good >> >> Reproduce steps: >> ---------------- >> 1 create L1 guest: >> qemu-system-x86_64 -enable-kvm -m 8G -smp 4 -net nic,macaddr=00:12:31:34:51:31 -net tap,script=/etc/kvm/qemu-ifup nested-kvm.qcow -cpu host >> >> 2. create L2 guest >> qemu-system-x86_64 -enable-kvm -m 2G -smp 2 -net none rhel6u5.qcow >> >> Current result: >> ---------------- >> create 64bit linux guest as L2 guest, the guest boots up fail >> >> Expected result: >> ---------------- >> create 64bit linux guest as L2 guest, the guest boots up fine >> >> Please take a look. >> > >Yong, according to the logs, I found that L1 may have disabled x2apic, >and the MSR_BITMAP field will be modified by following vmx_set_efer in >prepare_vmcs02. >So I think we can fix this issue by: > >diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >index f7b20b4..f6e3457 100644 >--- a/arch/x86/kvm/vmx.c >+++ b/arch/x86/kvm/vmx.c >@@ -2168,7 +2168,10 @@ static void vmx_set_msr_bitmap(struct kvm_vcpu *vcpu) > { > unsigned long *msr_bitmap; > >- if (irqchip_in_kernel(vcpu->kvm) && apic_x2apic_mode(vcpu->arch.apic)) { >+ if (is_guest_mode(vcpu)) >+ msr_bitmap = vmx_msr_bitmap_nested; >+ else if (irqchip_in_kernel(vcpu->kvm) && >+ apic_x2apic_mode(vcpu->arch.apic)) { > if (is_long_mode(vcpu)) > msr_bitmap = vmx_msr_bitmap_longmode_x2apic; > else > > >Thanks, >Wincy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/