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 0A459CCA481 for ; Thu, 14 Jul 2022 15:42:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239817AbiGNPmg (ORCPT ); Thu, 14 Jul 2022 11:42:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47638 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240011AbiGNPm2 (ORCPT ); Thu, 14 Jul 2022 11:42:28 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id A5E95501BF for ; Thu, 14 Jul 2022 08:42:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1657813346; 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=VOgvUYIncXWnFhKR1hAi50QlDyggks7WiA8ZUF17MI0=; b=fg9Up3dG5BJ1rBLTfg42pxeIH9RhD5efYv7NVENMK3zOs3Cf/ibQ3VpTheIsbc4qr132GP XfYmmGzXhKxMQdxftaM7hzqv9j+DztAyLD4Bxv3MvZ2nrDEQQcSCcIuhXNDhjux03p3YFN dK9fZOaxWVNqdiQmyn4naGlB4CT0j0A= Received: from mail-ej1-f70.google.com (mail-ej1-f70.google.com [209.85.218.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-606-YaNUFhGYNYukoTnTg8VB_Q-1; Thu, 14 Jul 2022 11:42:25 -0400 X-MC-Unique: YaNUFhGYNYukoTnTg8VB_Q-1 Received: by mail-ej1-f70.google.com with SMTP id gb37-20020a170907962500b0072b820af09dso909916ejc.20 for ; Thu, 14 Jul 2022 08:42:25 -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=VOgvUYIncXWnFhKR1hAi50QlDyggks7WiA8ZUF17MI0=; b=f2EqQzITBOVHg7c51eT4mMGtx+Yuw1ZBdRlXE5/XkfgeBRzhEHW4651Qm1IWRxvjTf VtPRxIyXAtOJFR+0KxEh04Wi5tZSCb6LneRk4ZKyuV2jUWHYKOAB8b/+gWpv1iJsEMyQ tqOWUoK3+zfuJP26MMyisQOAiseWIc9by3y2gyvI0JIW50RDpNBTvgyvo2SOIkHGbqd+ nwBWXGE0QoAJg7MdjE2F+myXtLo9JouWKhgEEaRKzLQNA5gfySR/P3aeO0ltnyMyfs9B P5q6q13TuMS1dqfwvIUWgx/qzng5jvh3WLzSB8Gj8BBtxInsaApIpvEyNWGU+HM6SQD0 i7Pw== X-Gm-Message-State: AJIora9xXfVoETsEdjNr+m1q23rdv/fE8lpuSvAvj1zhXfFhliMaJNQu DOyzV2zbuz0zlyk/w+P5aCuQlW3sDerJw1NoFS2xw5I1b9Z9+DlOqVPwEgO1dnGgbhfEJ3P+ZK2 DrFsYIfXbSEKY X-Received: by 2002:aa7:d155:0:b0:43a:bc8d:8d75 with SMTP id r21-20020aa7d155000000b0043abc8d8d75mr13060084edo.322.1657813344365; Thu, 14 Jul 2022 08:42:24 -0700 (PDT) X-Google-Smtp-Source: AGRyM1s7gve3iab4X/ADupNn/dQIy8nWtHC/Qs9AINATQpnZItpmwgA4FIBPCDi8iL7P+4KWrXVlCg== X-Received: by 2002:aa7:d155:0:b0:43a:bc8d:8d75 with SMTP id r21-20020aa7d155000000b0043abc8d8d75mr13060048edo.322.1657813344150; Thu, 14 Jul 2022 08:42:24 -0700 (PDT) Received: from ?IPV6:2001:b07:6468:f312:9af8:e5f5:7516:fa89? ([2001:b07:6468:f312:9af8:e5f5:7516:fa89]) by smtp.googlemail.com with ESMTPSA id v6-20020aa7d806000000b0043a754d53e5sm1231016edq.78.2022.07.14.08.42.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 14 Jul 2022 08:42:23 -0700 (PDT) Message-ID: Date: Thu, 14 Jul 2022 17:42:22 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH] KVM: selftests: Double check on the current CPU in rseq_test Content-Language: en-US To: Sean Christopherson Cc: Gavin Shan , kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com, shuah@kernel.org, maz@kernel.org, oliver.upton@linux.dev, shan.gavin@gmail.com References: <20220714080642.3376618-1-gshan@redhat.com> 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: kvm@vger.kernel.org On 7/14/22 17:35, Sean Christopherson wrote: >> Can you check that smp_rmb() and smp_wmb() generate correct instructions on >> arm64? > > That seems like the most likely scenario (or a kernel bug), I distinctly remember > the barriers provided by tools/ being rather bizarre. Maybe we should bite the bait and use C11 atomics in tools/. I've long planned an article "C11 atomics for kernel programmers", especially because this will also be an issue when Rust gets into the mix... Paolo