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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 EF766C433E7 for ; Thu, 15 Oct 2020 15:05:38 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4791722256 for ; Thu, 15 Oct 2020 15:05:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="pMpwPpWt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4791722256 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:46142 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kT4oy-0005eZ-OJ for qemu-devel@archiver.kernel.org; Thu, 15 Oct 2020 11:05:36 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:44104) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kT4h1-0006kU-5c for qemu-devel@nongnu.org; Thu, 15 Oct 2020 10:57:29 -0400 Received: from mail-ej1-x630.google.com ([2a00:1450:4864:20::630]:32995) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kT4gv-0002iN-HU for qemu-devel@nongnu.org; Thu, 15 Oct 2020 10:57:20 -0400 Received: by mail-ej1-x630.google.com with SMTP id c22so4119548ejx.0 for ; Thu, 15 Oct 2020 07:57:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=G0MtCDtWq/32YqRkQgDeY0B5ASaZ76/mMIxhaRr+/fo=; b=pMpwPpWtoVOjo5K05m+Kep9rlRTdq4hY/akrLz1CCA68nVvmGVgs8Xl2wKARLJRn5Q /ulFsgxcW00wW6SNnjhg5C+tzIBw9PZ9JkyRknB8nL36DX3CNWHvW32pRlgHUa9DJoiH MGGHCM/QUfRR/IpD1YFy35Mid8yQ+VtFMSWZUaDB5D1gsGTP02WhJgC5anoB86lcrmFR ZerCor+aCxkoc5pUy+R9mhlqjx+9fW9j5U5sVFdlrEbAsV4fsmsLlIV4iNnVzqoxFjtJ uD7kQEsP50h4Sq+KfrRQkCRyXl00WD2FPHpyCXqmrG8hnG7XZBChZZ0aLS0Jj43rstIy xxtw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=G0MtCDtWq/32YqRkQgDeY0B5ASaZ76/mMIxhaRr+/fo=; b=CJG0C7WGflk6rPKyhTg+R4k510UzkSEcD5eE1rriiOgIIYjm7uAt1DLE2JI37+2EGB gc+SkzxkfOMW4b7lHpdnwxxzQJz8ayQGz3VoeocvVTGkpB4rvjK9/2wbEaa8sTOqqZX2 kbLPkTI9nrHfku+UCzeptwkuz6f1LSbDaG5CUct8YVxdx4mIoZcRRA1gl3aBP1QZixpV B52/+Bmmbs5oMo6EjBBI4QU7Cg0TsQJjdXGElv3Jg4EZ6mWHzNqnkv0vuFJbtEPGRy3j JSlVVkcZ151Uv4PnEAmBOGc820JpDpjN0eNDhWhUpw3xEcIq++MOaCD1FAeJVHgTDs/f G87w== X-Gm-Message-State: AOAM530jMVNDXM0qPhAku3sqsd7p4jZS8vrqxtgCdk5P5qITKnLbcELJ 4EdBAmPJ7l4J8vE7Ha9qJM4Foh2Necu/12y6CTt2pQ== X-Google-Smtp-Source: ABdhPJz1lIzvU38dvHqcMsbMHkWrDPEAFvCVE/tsPnZNgvVnBLtWLnAF6/xb4n+B6xmwp1QrE+zLRNxC5Jt9Srh51a8= X-Received: by 2002:a17:906:3a97:: with SMTP id y23mr4946926ejd.250.1602773834128; Thu, 15 Oct 2020 07:57:14 -0700 (PDT) MIME-Version: 1.0 References: <20201015040639.70C6D414009F@webmail.sinamail.sina.com.cn> <7fecfc67da4caab1d677a8b4cd5386b3@kernel.org> <20201015133505.ubxvbrt6xyvl4362@kamzik.brq.redhat.com> <16400df4bdf79b8b22e824eb1a20e2b4@kernel.org> <20201015144104.ytwzpxjlsgyun3ob@kamzik.brq.redhat.com> In-Reply-To: <20201015144104.ytwzpxjlsgyun3ob@kamzik.brq.redhat.com> From: Peter Maydell Date: Thu, 15 Oct 2020 15:57:02 +0100 Message-ID: Subject: Re: Kernel patch cases qemu live migration failed. To: Andrew Jones Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2a00:1450:4864:20::630; envelope-from=peter.maydell@linaro.org; helo=mail-ej1-x630.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel , Marc Zyngier , xu910121@sina.com, "Dave.Martin" , kvmarm Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 15 Oct 2020 at 15:41, Andrew Jones wrote: > The reporter states neither the source nor destination hardware supports > SVE. My guess is that what's happening is the reserved ID register > ID_UNALLOCATED(4,4) was showing up in the KVM_GET_REG_LIST count on > the old kernel, but the new kernel filters it out. Maybe it is a > bug to filter it out of the count, as it's a reserved ID register and > I suppose the other reserved ID registers are still showing up? Yeah, RES0 ID registers should show up in the list, because otherwise userspace has to annoyingly special case them when the architecture eventually defines behaviour for them. Dave's comment in the kernel commit message # ID_AA64ZFR0_EL1 is RO-RAZ for MRS/MSR when SVE is disabled for the # guest, but for compatibility with non-SVE aware KVM implementations # the register should not be enumerated at all for KVM_GET_REG_LIST # in this case. seems wrong to me -- for compatibility the register should remain present and behave as RAZ/WI if SVE is disabled in the guest, the same way it was before the kernel/KVM knew about SVE at all. thanks -- PMM