From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752405AbdLMKUj (ORCPT ); Wed, 13 Dec 2017 05:20:39 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44396 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751121AbdLMKUf (ORCPT ); Wed, 13 Dec 2017 05:20:35 -0500 Subject: Re: [PATCH v8 1/4] KVM: X86: Add vCPU running/preempted state To: Wanpeng Li , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Peter Zijlstra , Wanpeng Li References: <1513128784-5924-1-git-send-email-wanpeng.li@hotmail.com> <1513128784-5924-2-git-send-email-wanpeng.li@hotmail.com> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <3fb56993-3bb6-442c-f12e-0c99c06ef5c2@redhat.com> Date: Wed, 13 Dec 2017 11:20:32 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <1513128784-5924-2-git-send-email-wanpeng.li@hotmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Wed, 13 Dec 2017 10:20:35 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13.12.2017 02:33, Wanpeng Li wrote: > From: Wanpeng Li > > This patch reuses the preempted field in kvm_steal_time, and will export > the vcpu running/pre-empted information to the guest from host. This will > enable guest to intelligently send ipi to running vcpus and set flag for > pre-empted vcpus. This will prevent waiting for vcpus that are not running. > > Cc: Paolo Bonzini > Cc: Radim Krčmář > Cc: Peter Zijlstra > Signed-off-by: Wanpeng Li > --- > arch/x86/include/uapi/asm/kvm_para.h | 3 +++ > arch/x86/kernel/kvm.c | 2 +- > arch/x86/kvm/x86.c | 4 ++-- > 3 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h > index 09cc064..763b692 100644 > --- a/arch/x86/include/uapi/asm/kvm_para.h > +++ b/arch/x86/include/uapi/asm/kvm_para.h > @@ -51,6 +51,9 @@ struct kvm_steal_time { > __u32 pad[11]; > }; > > +#define KVM_VCPU_NOT_PREEMPTED (0 << 0) > +#define KVM_VCPU_PREEMPTED (1 << 0) Is it really helpful to have two flags? Just use KVM_VCPU_PREEMPTED and clear that one in record_steal_time() -- Thanks, David / dhildenb