From patchwork Fri May 12 23:50:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 93426 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp5462647vqo; Fri, 12 May 2023 16:53:15 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ4/JHiKV7LYrkzzs5UZb9lkut2E73o3yBT+EMdPBM/VUw8utwv+mv/eib2vjZ1yzje5ga2F X-Received: by 2002:a05:6a20:3d26:b0:101:69ad:e488 with SMTP id y38-20020a056a203d2600b0010169ade488mr19405223pzi.29.1683935595697; Fri, 12 May 2023 16:53:15 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1683935595; cv=none; d=google.com; s=arc-20160816; b=VaXmsbTee1/nwKlcch+F7paWhJh7+sY2DH/bYtV1lUa0YQ6/Kem78e4EECtnO6CA+B npzt3w98u9TS10OFjGykOUc/ZLs6l4y3EDJKwavsZXxcql0WIAnrkjED+2Y1G9XVlxJ5 tO8ZRl5vVcbZtGj1d+N02Zko3RxYCRqiaUvMAFFZI8XlUFIl9TSZZ9juUQzkOWLMOaru eM2Z2vigAJCbh1BfIHHDMUrVglPkEGJZyIeJeNsTggVgsa9DrZeYTOLOKLwaX6KliTjm fzW6FTlwDzjKhJeUycFaxjrMCQSyh2o6DEeGKpPiYhZDxH2u7FUX6krv0qE6+IcTI7EN 7VVg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:reply-to:dkim-signature; bh=0PGjBuYsH+qENFwlP6YIflCQgyh/+jY7Rp+4isY3uAw=; b=G36tnYCZ/GnciNVuarPMw0EzmDdXWFbnlLuU5XMFH56dszYitZQwKd5V6+VvYqNYOm gxPEvN1HrYUcsNMDEWSGCCtoib1V/6Ma53/wh1TTAFkIkpm61T9J0rwsuxLJTTYZM+sm fAtybpiLGLDM9Yew/NwEDerrR+IJW7tS9pu/jCC/7Zi17ZOkZXm9O8pjECqIEjBPJkzW mKvlcqd2GnDKgA9WsCULoR7tPgClogrYI3KXzwX/0qny+7Rh7HVkGhbT1L1EnqHEJHwQ UF2TgdRPGq0lXePDIQrs8TQZcarD46Nt2jA1+ThiNSPJbnZEdATBSBcdUQT2XDXxPQcI fMag== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=IpfXQKDN; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id bk13-20020a056a02028d00b0052c9fb2c7e2si10357266pgb.900.2023.05.12.16.53.03; Fri, 12 May 2023 16:53:15 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=IpfXQKDN; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241005AbjELXvD (ORCPT + 99 others); Fri, 12 May 2023 19:51:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51108 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240999AbjELXuu (ORCPT ); Fri, 12 May 2023 19:50:50 -0400 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D32164204 for ; Fri, 12 May 2023 16:50:41 -0700 (PDT) Received: by mail-pf1-x44a.google.com with SMTP id d2e1a72fcca58-643fdfb437aso37898819b3a.0 for ; Fri, 12 May 2023 16:50:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1683935441; x=1686527441; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=0PGjBuYsH+qENFwlP6YIflCQgyh/+jY7Rp+4isY3uAw=; b=IpfXQKDNfq33fpp3TPAvdomMbm4Tbp6Xj0gdNAonYxvAp7JiZH8DmMQtZ9srWRapbz uC7LCmu5T5/VGui1txQ58MH0oCADW5St/+sfDoVIdQXRmFDLDMqeb+YXOELs57FobABo W2VW19HXHMjvv7XhXhLW/3HE5P/QkjRtL+OavFPe7HpQtrOtUGG9nau0a9TrCMXLj/j9 HgpwQhjgvU153Dot5mlhrfTuKsstno+0N2i/DoQQh31g90SbOl2XZqe9Lh6QhQ1EWwxN vYiHuv0qOtY5g2x/zkKecxGT0507wZyf4a0QiN2eJOil/pkK5+ime7jlXipteWR+kVjL aHYA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683935441; x=1686527441; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=0PGjBuYsH+qENFwlP6YIflCQgyh/+jY7Rp+4isY3uAw=; b=Unv891HwcDPnsCikyLomAUQRp13toYvNt/FAxcoODsvkfoEXL4yr8/BjvNB2PyHOjz 2BPRpayKTYopVrhhORu9x3EXEx9qCjNlyAXKmVR+UJzB6VP3QM2AgikNc+VSFAj6DF5E 64sDj+lJZbPfh3Txf/XWNyJD8DgSoTIQHRL+zB5ynvlvkwJyooMluHLmXKvW/CLuR7xQ Te8+fmACN5dPtoKLRx2x0nFEwis9GlLkpsHQSzJQYeiXas1o3SCpR5aX02/EcvrlXTkH KWVSFaILnU2eHUnSiYicOpJ8lV+j0wFJFGSUnLfVxZetg/KENvOsix3Qv7XLQ2j0KsO8 W3vA== X-Gm-Message-State: AC+VfDxvQQNrxfe+/LCYrZLIWoi97b2Vu4mWmMkbi6HQScRXdiWDwjIP TEXGvorLmB/wtbAMXJOdzs9d9EDPBmo= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90a:6f81:b0:24b:6d01:584a with SMTP id e1-20020a17090a6f8100b0024b6d01584amr8598399pjk.0.1683935441288; Fri, 12 May 2023 16:50:41 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 12 May 2023 16:50:14 -0700 In-Reply-To: <20230512235026.808058-1-seanjc@google.com> Mime-Version: 1.0 References: <20230512235026.808058-1-seanjc@google.com> X-Mailer: git-send-email 2.40.1.606.ga4b1b128d6-goog Message-ID: <20230512235026.808058-7-seanjc@google.com> Subject: [PATCH v3 06/18] x86/reboot: Assert that IRQs are disabled when turning off virtualization From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Andrew Cooper , Kai Huang , Chao Gao X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1765734451483714338?= X-GMAIL-MSGID: =?utf-8?q?1765734451483714338?= Assert that IRQs are disabled when turning off virtualization in an emergency. KVM enables hardware via on_each_cpu(), i.e. could re-enable hardware if a pending IPI were delivered after disabling virtualization. Remove a misleading comment from emergency_reboot_disable_virtualization() about "just" needing to guarantee the CPU is stable (see above). Signed-off-by: Sean Christopherson Reviewed-by: Kai Huang --- arch/x86/kernel/reboot.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index 20f7bdabc52e..fddfea5f1d20 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -531,7 +531,6 @@ static inline void nmi_shootdown_cpus_on_restart(void); static void emergency_reboot_disable_virtualization(void) { - /* Just make sure we won't change CPUs while doing this */ local_irq_disable(); /* @@ -820,6 +819,13 @@ void cpu_emergency_disable_virtualization(void) { cpu_emergency_virt_cb *callback; + /* + * IRQs must be disabled as KVM enables virtualization in hardware via + * function call IPIs, i.e. IRQs need to be disabled to guarantee + * virtualization stays disabled. + */ + lockdep_assert_irqs_disabled(); + rcu_read_lock(); callback = rcu_dereference(cpu_emergency_virt_callback); if (callback)