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 8662FC77B7A for ; Fri, 19 May 2023 21:02:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230250AbjESVCP (ORCPT ); Fri, 19 May 2023 17:02:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229515AbjESVCN (ORCPT ); Fri, 19 May 2023 17:02:13 -0400 Received: from mail-pf1-x449.google.com (mail-pf1-x449.google.com [IPv6:2607:f8b0:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 605831A5 for ; Fri, 19 May 2023 14:02:11 -0700 (PDT) Received: by mail-pf1-x449.google.com with SMTP id d2e1a72fcca58-6435432f56bso2365889b3a.3 for ; Fri, 19 May 2023 14:02:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1684530131; x=1687122131; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:from:to:cc:subject:date:message-id :reply-to; bh=Mw3Ozc4fZg2tj7CT8Q6YsEZOU9HXZu7Pqk3RzFDGAeg=; b=hNqb88g2Aeap67x1FMTjGHF4R/Xg7gRRWKuiWZSgR63RmDKjcslfpiMQ/XEeL3j6+R DG31pafPWlx0zaTuIJ4RwvepIWrUKJFkVkKtod5fcTr6Hu+JKiJAJEPtnRMdAe+0BPR2 gIs18PQLRxZY1NDqP1K8Xvdfw+ys4n2aNDSCWQqsrD+CunKeFcuP47lED449bgiSsOjO p+CVxQuMmoH0SEbHGDeBe6TQHCAz91qxWyiq8FmWzP1GXons1ME+1VMdGnLBa9oDebnU Q3ARPv/fHksN59aDO1JExSqEtmCobGVo2EuvLXstm3Va95C+HI/C1YrV+0Iyr6iW/FY0 FPxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1684530131; x=1687122131; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=Mw3Ozc4fZg2tj7CT8Q6YsEZOU9HXZu7Pqk3RzFDGAeg=; b=GaPGZX4ifMnVAxyRiEfPdCoxCLFWEVOdqhaY5Ol/6THyXTzNnfflmCX7Qi95YScAsZ b6sadVFPuF8CE74GbgZsEkA6FU+aBrG4ZddippvdFSVysE0LBltVNpJaUqKTM0Uhb8mf 85vwPK3Y/H053rIth5XPxU70qP/nNcACNpQDF4yww43hP379ruC3/SUDf3nVUGLim0zC Aef1qwixCzw+8f2dNijuPLXDX+sne1CZHjTkqYFiZjRbkdGu5O29KEvijZZLzfKaSyH/ W3C4zq73FoiVZSA8Irp2fm770t/Csdcr9vB6I8LbYmYofiAqO0jktG0QUzTKkfx4QGUR 8jDw== X-Gm-Message-State: AC+VfDyvHjGXqZJtb0bzGTOrzvaC6Ea50sNG7zaWsIw16i3KRoZn3wSc y/BAzDK2tYJ0gaG8CHmFogvkxins14w= X-Google-Smtp-Source: ACHHUZ7NvdrVLKzYiaTxHRsLQSoMdRHj0JrAs5j8t7q4YRdK3vLRz1AQvmxSAVOq0KKowdDTiH0p7G2+xFQ= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6a00:2d28:b0:63b:1a20:5ea2 with SMTP id fa40-20020a056a002d2800b0063b1a205ea2mr1615463pfb.1.1684530130898; Fri, 19 May 2023 14:02:10 -0700 (PDT) Date: Fri, 19 May 2023 14:02:09 -0700 In-Reply-To: Mime-Version: 1.0 References: <20230404122652.275005-1-aleksandr.mikhalitsyn@canonical.com> <20230404122652.275005-3-aleksandr.mikhalitsyn@canonical.com> Message-ID: Subject: Re: [PATCH 2/2] KVM: SVM: add some info prints to SEV init From: Sean Christopherson To: Aleksandr Mikhalitsyn Cc: pbonzini@redhat.com, "=?iso-8859-1?Q?St=E9phane?= Graber" , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, May 19, 2023, Aleksandr Mikhalitsyn wrote: > On Fri, May 19, 2023 at 8:17=E2=80=AFPM Sean Christopherson wrote: > > > > On Tue, Apr 04, 2023, Alexander Miqqqqkhalitsyn wrote: > > > Let's add a few pr_info's to sev_hardware_setup to make SEV/SEV-ES > > > enabling a little bit handier for users. Right now it's too hard > > > to guess why SEV/SEV-ES are failing to enable. > > > > Hmm, I'm somewhat torn, but I'm against taking this patch, at least not= in its > > current form. I appreciated that determining why KVM isn't enabling SE= V/SEV-ES > > is annoying, but there's very little actionable information provided he= re that > > isn't also super obvious. I also don't want to start us down a slipper= y slope > > of printing out messages every time KVM doesn't enable a feature. > > > > If someone tries to enable SEV and doesn't check that their CPU support= s SEV, > > then IMO that's on them. Ditto for SEV-ES. > > > > The NPT thing is mildly interesting, but practically speaking I don't e= xpect that > > to ever be a hindrace for generic enabling. Ditto for MMIO caching. > > > > The decode assists check is (a) completely unactionable for the vast, v= ast majority > > of users and (b) is a WARN_ON_ONCE() condition. > > > > The ASID stuff is by far the most interesting, but that's also quite in= teresting > > for when SEV and SEV-ES _are_ fully supported. > > > > So if we want to provide the user more info, I'd prefer to do something= like the > > below, which I think would be more helpful and would avoid my slippery = slope > > concerns. >=20 > Dear Sean, >=20 > Thanks for looking into this! >=20 > I agree with your points, let's go that way and print only ASID stuff > as it can be not obvious to the end-user. >=20 > I'm ready to prepare -v2 if you don't mind. Ya, fire away. Thanks!