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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49740C6778F for ; Wed, 25 Jul 2018 08:37:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F320920844 for ; Wed, 25 Jul 2018 08:37:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F320920844 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728676AbeGYJs0 (ORCPT ); Wed, 25 Jul 2018 05:48:26 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:54608 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728357AbeGYJsZ (ORCPT ); Wed, 25 Jul 2018 05:48:25 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 23BE08550F; Wed, 25 Jul 2018 08:37:47 +0000 (UTC) Received: from vitty.brq.redhat.com.redhat.com (unknown [10.40.205.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D8CEB111DCE8; Wed, 25 Jul 2018 08:37:43 +0000 (UTC) From: Vitaly Kuznetsov To: Paolo Bonzini Cc: kvm@vger.kernel.org, Radim =?utf-8?B?S3LEjW3DocWZ?= , Roman Kagan , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , "Michael Kelley \(EOSG\)" , Mohammed Gamal , Cathy Avery , linux-kernel@vger.kernel.org, Jim Mattson , Liran Alon Subject: Re: [PATCH v2 6/6] KVM: nVMX: optimize prepare_vmcs02{,_full} for Enlightened VMCS case References: <20180621123046.29606-1-vkuznets@redhat.com> <20180621123046.29606-7-vkuznets@redhat.com> Date: Wed, 25 Jul 2018 10:37:43 +0200 In-Reply-To: (Paolo Bonzini's message of "Tue, 24 Jul 2018 19:09:04 +0200") Message-ID: <87va93pv6w.fsf@vitty.brq.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Wed, 25 Jul 2018 08:37:47 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Wed, 25 Jul 2018 08:37:47 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'vkuznets@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Paolo Bonzini writes: > On 21/06/2018 14:30, Vitaly Kuznetsov wrote: >> +static __always_inline bool evmcs_needs_write(struct vcpu_vmx *vmx, >> + u16 clean_field) >> +{ >> + if (vmx->nested.dirty_vmcs12) >> + return true; > > Why is this needed? If it weren't for it, you could pass hv_evmcs > directly to evmcs_needs_write, which would simplify the code a bit in > the caller. This is an equivalent of prepare_vmcs02()/prepare_vmcs02_full() split for eVMCS case: when we switch from L2 guest A to L2 guest B we need to write the whole VMCS so evmcs_needs_write() needs to return true. We can, however, make an optimisation: forcefuly reset hv_clean_fields mask on enlightened vmptrld making 'dirty_vmcs12' check redundant. This series was posted quite some time ago, I'll rebase and re-test with the fix included. Thanks! -- Vitaly