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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0875EC433EF for ; Mon, 27 Sep 2021 11:13:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DEBE360F46 for ; Mon, 27 Sep 2021 11:13:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233968AbhI0LPM (ORCPT ); Mon, 27 Sep 2021 07:15:12 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:46792 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233948AbhI0LPJ (ORCPT ); Mon, 27 Sep 2021 07:15:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632741211; 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=7tSoUz2N0qF0zb0Et/cte83XJDDHfriVu1jQ2m+uNHw=; b=fDEsLsO0zu2ctxyqb9sCm5gayFwRKzKbbYQobo5n70hxJdmSyGaCKyiARk91Tdb7E3367v BxZA9h25uV6DynPxZ+3RDJop+xKTSqFUSIPuRRqf0yihKdytAvxQ5FOm85+C7urgDCNYvn 1ofNZJKSFbc+QU00+QxY8ZVVCfmf4NI= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-536-AIzsHSvaNDObrM_SaIYbvQ-1; Mon, 27 Sep 2021 07:13:30 -0400 X-MC-Unique: AIzsHSvaNDObrM_SaIYbvQ-1 Received: by mail-ed1-f70.google.com with SMTP id c36-20020a509fa7000000b003da5a9e5d68so6590336edf.15 for ; Mon, 27 Sep 2021 04:13:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=7tSoUz2N0qF0zb0Et/cte83XJDDHfriVu1jQ2m+uNHw=; b=7FTulJpy7DYIxWOtkh1WrP5c4pHVuR9GiptpJzGPQtUXw5WGt6MT9d/wFOnvJ/V6M9 Y0KcMMKBglkKNGPxO8zYKUqrXp4Ky70UGCTPw2azMn8XAidHIs7GEKZb91R3a71dFjix VLSgHUPfkmm7xbrrvbHKOyQrGtW0PrHAiHimfyjWwdnX2jABG6qEZwwMs1ce0YYPMozK epQQmeM+JdEFoQ1oEkHev8wNuc714d5J32uEW/CO//GZqr/B2AaU4cSWcxRbjuJiiPZA S8Nx2ug5zFCSUV/vvRI6O8KFSjU/OUvJnXCBdGQk9evLF/RwPmqCIpenH+5Zk9Qlh0qX qwPA== X-Gm-Message-State: AOAM533Qs5QcTwOSv5L9Ry8NIIEcWsA2IgS+eX+8IGeDTxfYkTtwvDlV ZSiFrO9kLZhLVa6l9sTYjQ7kDjLUY5TQIssxV19Ty6uggVvgYt2InLxqeQBPVHVzxDilieIWg+L fY6clxOqFAWKjwUxlw+gTuW+I X-Received: by 2002:a05:6402:51d2:: with SMTP id r18mr22609376edd.108.1632741209110; Mon, 27 Sep 2021 04:13:29 -0700 (PDT) X-Google-Smtp-Source: ABdhPJz5RvtOHWYR+utbtWs3XCi1myI6/TvDCQG0lXgTUXxR6H4yPccUvoVamO+Lk19ceP7uPQfFIw== X-Received: by 2002:a05:6402:51d2:: with SMTP id r18mr22609343edd.108.1632741208936; Mon, 27 Sep 2021 04:13:28 -0700 (PDT) Received: from ?IPV6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id u2sm10370698eda.32.2021.09.27.04.13.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 27 Sep 2021 04:13:28 -0700 (PDT) Message-ID: Date: Mon, 27 Sep 2021 13:13:26 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.1.0 Subject: Re: [PATCH] KVM: x86: Expose Predictive Store Forwarding Disable Content-Language: en-US To: Borislav Petkov , Babu Moger Cc: tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, hpa@zytor.com, seanjc@google.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, tony.luck@intel.com, peterz@infradead.org, kyung.min.park@intel.com, wei.huang2@amd.com, jgross@suse.com, andrew.cooper3@citrix.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org References: <163244601049.30292.5855870305350227855.stgit@bmoger-ubuntu> From: Paolo Bonzini In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27/09/21 12:59, Borislav Petkov wrote: > On Thu, Sep 23, 2021 at 08:15:28PM -0500, Babu Moger wrote: >> Linux kernel does not have the interface to enable/disable PSFD yet. Plan >> here is to expose the PSFD technology to KVM so that the guest kernel can >> make use of it if they wish to. > > Why should the guest kernel expose it if we said that for now we want to > disable it with the SSBD control? Because the guest kernel needs to know which MSRs to write when you touch the SSBD prctl, so that PSFD is properly disabled *inside the guest*. Paolo