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 A2385C7EE29 for ; Wed, 7 Jun 2023 08:16:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238969AbjFGIQg (ORCPT ); Wed, 7 Jun 2023 04:16:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238845AbjFGIQc (ORCPT ); Wed, 7 Jun 2023 04:16:32 -0400 Received: from mail-il1-x131.google.com (mail-il1-x131.google.com [IPv6:2607:f8b0:4864:20::131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8682D1BD2; Wed, 7 Jun 2023 01:16:11 -0700 (PDT) Received: by mail-il1-x131.google.com with SMTP id e9e14a558f8ab-33d31ab00bdso1795025ab.3; Wed, 07 Jun 2023 01:16:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1686125771; x=1688717771; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=/lHKaHlKRBzKcxVY9qtbqRsvCzEYo5afOE+RIHn1VXQ=; b=BDzZgP/pH5q49SPa8RpHncHkn4Q08LDmFjb3IxQmNKuuEu5Yny7OuDwgeD+OlrKUXz +x8FiHlJ1hh/B+RAQZpNeVdjAS+6baat0mfjI/qfLojs4km51n5vKzE3q+mDxoZKKSt6 YE9kWrORw4uVczvTRKQJcgz8maXrpBU4FHMJQwE4Kk4EvIxBAtlGBOQPI9OYIxHF2VdB bWNZ3YLyjHfA5k6mltDS/C30t9hop8NgGZ4lUjVTF1tD/XXtYnMnKQOZ+RCwvcHLOtZp SRH8+iIMq/6m/SAgZQXX3HMFLJI9sRCWBUMl8mcLWqb85ghURDW2S6jwohC1unHJVYl/ u3GA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686125771; x=1688717771; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=/lHKaHlKRBzKcxVY9qtbqRsvCzEYo5afOE+RIHn1VXQ=; b=BkYL93kg+sMkuKzv8jamMvxWSqVEinoZbXOilnU3i8wDFSyGwT9Z58UbCEIKyA/xho EzdiRGRaAIBH+ts4eQXmsFAlAJ/aXJwHC89BcwjUYrgbuF9xmHf0sV5SU36jBWW5uIgT gVN+XnoS1nA2wHaLTcy+XN9B3HFLcJifPM19wmcAfWNZ5ae2J0GoXTflu+PszQpa+3Eg U8tz3RP1g7M+lreeSmbhyNHtCgCtuYJAqgjrcl5FVWhXFhS+wYjpyj8b99EbHquwIw17 D9Fy8fKf4o34MFd9Pajm/WaqLn7ehLieku/6QG9aEaKam63s7eK5TudPcWae4lrbBBl0 GyrQ== X-Gm-Message-State: AC+VfDxWjTJRJffp7+iMqnJyqnz0X8ZzPzqIpZK9wx1jXFMuuLKvXYXb bzXVLuQ0EmN8cYiFuRrMp6A= X-Google-Smtp-Source: ACHHUZ6JRZbxoBk987Tly0PiTO2/uCJrh3Tp2DcsOU05a0kZ0UzEX3QdH47ft+pRhC0/wSIE54PcUw== X-Received: by 2002:a92:ce45:0:b0:33b:ad04:2c31 with SMTP id a5-20020a92ce45000000b0033bad042c31mr5308840ilr.8.1686125770834; Wed, 07 Jun 2023 01:16:10 -0700 (PDT) Received: from ?IPV6:2404:f801:0:5:8000::75b? ([2404:f801:9000:18:efec::75b]) by smtp.gmail.com with ESMTPSA id y5-20020a63ce05000000b005346b9a7fe5sm8621285pgf.22.2023.06.07.01.16.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 07 Jun 2023 01:16:10 -0700 (PDT) Message-ID: <2803e5d6-58bc-57f1-0721-226333238883@gmail.com> Date: Wed, 7 Jun 2023 16:16:03 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.11.2 Subject: Re: [PATCH 4/9] drivers: hv: Mark shared pages unencrypted in SEV-SNP enlightened guest To: Vitaly Kuznetsov , kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, daniel.lezcano@linaro.org, arnd@arndb.de, michael.h.kelley@microsoft.com Cc: Tianyu Lan , linux-arch@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230601151624.1757616-1-ltykernel@gmail.com> <20230601151624.1757616-5-ltykernel@gmail.com> <87zg5ejchp.fsf@redhat.com> From: Tianyu Lan In-Reply-To: <87zg5ejchp.fsf@redhat.com> 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 6/5/2023 8:54 PM, Vitaly Kuznetsov wrote: >> @@ -402,7 +417,14 @@ int hv_common_cpu_die(unsigned int cpu) >> >> local_irq_restore(flags); >> >> - kfree(mem); >> + if (hv_isolation_type_en_snp()) { >> + ret = set_memory_encrypted((unsigned long)mem, pgcount); >> + if (ret) >> + pr_warn("Hyper-V: Failed to encrypt input arg on cpu%d: %d\n", >> + cpu, ret); >> + /* It's unsafe to free 'mem'. */ >> + return 0; > Why is it unsafe to free 'mem' if ret == 0? Also, why don't we want to > proparate non-zero 'ret' from here to fail CPU offlining? > Based on Michael's patch the mem will not be freed during cpu offline. https://lwn.net/ml/linux-kernel/87cz2j5zrc.fsf@redhat.com/ So I think it's unnessary to encrypt the mem again here.