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 5DBEEC4332F for ; Mon, 16 May 2022 20:34:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244731AbiEPUeF (ORCPT ); Mon, 16 May 2022 16:34:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40330 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349186AbiEPUcO (ORCPT ); Mon, 16 May 2022 16:32:14 -0400 Received: from mail-pl1-x62e.google.com (mail-pl1-x62e.google.com [IPv6:2607:f8b0:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79956220D0 for ; Mon, 16 May 2022 13:16:17 -0700 (PDT) Received: by mail-pl1-x62e.google.com with SMTP id d22so15499541plr.9 for ; Mon, 16 May 2022 13:16:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=eEf303JFQr27w0Vt+K07oyfUlhM8ngQeghXsWAlSwH4=; b=IKLOHQm2ajjJD3zfYAXlQZxSzcodxxKtRJ5h/jXk42qggHsRPKw+FFz3WeVVUrup/6 +GPtLWnGZDyFJ2+YTix41B7mSK6h3oG95eqdNCKRuGJXswh3tZVVEtMSIVC2Zqbpt2NV mcVl5xiU48XAZdetvRJRQNBh8Yi5Ag/9SlihX9FHbtH5wUIA3AEX30yabOmf6GP/rAjf Cz/Lnmb3SdW7+s762tUxq3yFngRcIqOZ5BJuIPDrIGB1bkjTyXfSMtv0hpxMFz/L4vuc CdvpnOJ1eHcwGxxKnAUKJ8WZTp57sw4ALgsgxwH2eToFNACX2/Z+VoD90qtdebwsYwo5 tSkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=eEf303JFQr27w0Vt+K07oyfUlhM8ngQeghXsWAlSwH4=; b=6pRaELWxHNbxEIjRwGd0M4gRPa5MYBL3QQIQB3vKkfL54HUzdOba9cq6Dvt8lpRtgL Qz9DkGJgBgJGFrtCvSiu5Y1XCxLMm9GdsiMPb9onQdWHyMHORR2rzI6LEZK7WDCpuh8W 8MMlqb9OK1kCM1/QH//DmjZ6KPPY0jmntPG8cffk45Mz3gEyKqBURZT9ff9B5sqqogqS cfq/wlgm79qacS6J7PS5vfvg8aY12QYG2e9BcWkK/Qomssie457VWRSmcU8FeCAk2iR0 CAJC1XNsU40m+nSNyBZGo3KQdA9CtXxOk4ZKqJ9QYosGv8I/G6rmvOsgw+kYNiRaMtpt STfA== X-Gm-Message-State: AOAM533/nope2Tc97NHQvWJ2dGG+goenBHkfMEJ/ZRvxIwawiwq0xWgo lFnTNurUyyTLcz/oCiAbiri1kg== X-Google-Smtp-Source: ABdhPJykKyOAnItGqLNia7022tjeLb/8kmYyTzBSKpYjXaZe7Rw+w2V9L8itS02vwdLcXf78wpx5OQ== X-Received: by 2002:a17:90b:505:b0:1de:ffef:6167 with SMTP id r5-20020a17090b050500b001deffef6167mr16471499pjz.172.1652732176891; Mon, 16 May 2022 13:16:16 -0700 (PDT) Received: from google.com (157.214.185.35.bc.googleusercontent.com. [35.185.214.157]) by smtp.gmail.com with ESMTPSA id e8-20020a170902784800b0015e8d4eb254sm7419120pln.158.2022.05.16.13.16.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 May 2022 13:16:16 -0700 (PDT) Date: Mon, 16 May 2022 20:16:13 +0000 From: Sean Christopherson To: Maxim Levitsky Cc: Vitaly Kuznetsov , kvm@vger.kernel.org, Paolo Bonzini , Wanpeng Li , Jim Mattson , Michael Kelley , Siddharth Chandrasekaran , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 19/34] KVM: nVMX: hyper-v: Enable L2 TLB flush Message-ID: References: <20220414132013.1588929-1-vkuznets@redhat.com> <20220414132013.1588929-20-vkuznets@redhat.com> <3d25a230ec31161823c6320ceef77ab0c331e3d1.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3d25a230ec31161823c6320ceef77ab0c331e3d1.camel@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Wed, May 11, 2022, Maxim Levitsky wrote: > On Thu, 2022-04-14 at 15:19 +0200, Vitaly Kuznetsov wrote: > > +/* > > + * Note, Hyper-V isn't actually stealing bit 28 from Intel, just abusing it by > > + * pairing it with architecturally impossible exit reasons. Bit 28 is set only > > + * on SMI exits to a SMI transfer monitor (STM) and if and only if a MTF VM-Exit > > + * is pending. I.e. it will never be set by hardware for non-SMI exits (there > > + * are only three), nor will it ever be set unless the VMM is an STM. > > I am sure that this will backfire this way or another. Their fault though... Heh, that was my initial reaction too, but after working through the architecture I gotta hand it to the Hyper-V folks, it's very clever :-) And if we ever need a synthetic exit reason for PV KVM... :-)