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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C58AC352A1 for ; Tue, 6 Dec 2022 12:14:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234210AbiLFMOg (ORCPT ); Tue, 6 Dec 2022 07:14:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230230AbiLFMOd (ORCPT ); Tue, 6 Dec 2022 07:14:33 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F089EB67 for ; Tue, 6 Dec 2022 04:13:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1670328816; 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=Rx3yhRSNQLXKIbD5wZaN6jZW0LIMtSAtWlXbIFkz/ZU=; b=DbQReOI9JQ4UUbBAskQ3P8chNdclQRJl1YF092hh457ASsiK1LVuWMuQ+x7JaHAZ1f5g4v XoN7K+MQEjuu8M/GQ9oe00uiW33Dp2iHgykumuZJDz07FoGUjdgoXv1h/hg4y10BIwt8NH r6kZ2HB+V62EF49TknX9qLblTrEz9D8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-644-85G02iPANG6YVtn8B3hdrw-1; Tue, 06 Dec 2022 07:13:32 -0500 X-MC-Unique: 85G02iPANG6YVtn8B3hdrw-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C1572101A528; Tue, 6 Dec 2022 12:13:31 +0000 (UTC) Received: from starship (unknown [10.35.206.46]) by smtp.corp.redhat.com (Postfix) with ESMTP id D85DD4A9279; Tue, 6 Dec 2022 12:13:27 +0000 (UTC) Message-ID: <439f0b8b52dd019c60974ab105dee75fa15eaf3e.camel@redhat.com> Subject: Re: [PATCH v2 01/11] KVM: nSVM: don't sync back tlb_ctl on nested VM exit From: Maxim Levitsky To: Santosh Shukla , kvm@vger.kernel.org Cc: Sandipan Das , Paolo Bonzini , Jim Mattson , Peter Zijlstra , Dave Hansen , Borislav Petkov , Pawan Gupta , Thomas Gleixner , Ingo Molnar , Josh Poimboeuf , Daniel Sneddon , Jiaxi Chen , Babu Moger , linux-kernel@vger.kernel.org, Jing Liu , Wyes Karny , x86@kernel.org, "H. Peter Anvin" , Sean Christopherson Date: Tue, 06 Dec 2022 14:13:26 +0200 In-Reply-To: <946d0a77-eecb-5e30-716b-1d6cffd7f12c@amd.com> References: <20221129193717.513824-1-mlevitsk@redhat.com> <20221129193717.513824-2-mlevitsk@redhat.com> <946d0a77-eecb-5e30-716b-1d6cffd7f12c@amd.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 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2022-12-05 at 19:35 +0530, Santosh Shukla wrote: > Hi Maxim, > > On 11/30/2022 1:07 AM, Maxim Levitsky wrote: > > The CPU doesn't change TLB_CTL value as stated in the PRM (15.16.2): > > > nits: > s / PRM (15.16.2) / APM (15.16.1 - TLB Flush) True for both changes, thanks! Best regards, Maxim Levitsky > > > "The VMRUN instruction reads, but does not change, the > > value of the TLB_CONTROL field" > > > > Therefore the KVM shouldn't do that either. > > > > Signed-off-by: Maxim Levitsky > > --- > > arch/x86/kvm/svm/nested.c | 1 - > > 1 file changed, 1 deletion(-) > > > > diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c > > index bc9cd7086fa972..37af0338da7c32 100644 > > --- a/arch/x86/kvm/svm/nested.c > > +++ b/arch/x86/kvm/svm/nested.c > > @@ -1010,7 +1010,6 @@ int nested_svm_vmexit(struct vcpu_svm *svm) > > vmcb12->control.next_rip = vmcb02->control.next_rip; > > > > vmcb12->control.int_ctl = svm->nested.ctl.int_ctl; > > - vmcb12->control.tlb_ctl = svm->nested.ctl.tlb_ctl; > > vmcb12->control.event_inj = svm->nested.ctl.event_inj; > > vmcb12->control.event_inj_err = svm->nested.ctl.event_inj_err; > >