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[2620:137:e000::1:20]) by mx.google.com with ESMTP id h6-20020a170902f54600b001a96b56099fsi10628045plf.404.2023.05.12.14.19.13; Fri, 12 May 2023 14:19:27 -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=@linutronix.de header.s=2020 header.b=okTigxEm; dkim=neutral (no key) header.i=@linutronix.de header.s=2020e header.b=6Ab3fDB1; 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=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240139AbjELVIp (ORCPT + 99 others); Fri, 12 May 2023 17:08:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239975AbjELVHz (ORCPT ); Fri, 12 May 2023 17:07:55 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EEB2AE71A; Fri, 12 May 2023 14:07:28 -0700 (PDT) Message-ID: <20230512205256.369512093@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1683925644; 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: references:references; bh=PMK22/HxoxSZKsTx+MtkiiSihvL00YPGs/TFPEL6TlU=; b=okTigxEmoNFjuISzZ3w6/Y2KcJueXtK98ysR49cIhhmzWitrnTsrr30PPjCUMPXry4xftP J52lH1DVgnpuG/Rfq4wLyAmr6aBgTzg3Kcpzk53VYvl1lEluUMhVlu3W9w3D8aZ28W1fnU FYwd2Sfv1zxIrxvZkgBRqufQ3iNj4eO+ry/ohM+Ld/vwoFregiASpdqfC0/pYtJYsd1OgL Vlb3BzT7+3vJnR5zuW45X4PcDsWr4so0XRPW7RLUs94CbintoxNd6G1JVdbZNrIt24RqAz 6rW20AhO6LWDKJUuEPLhETfdZ7aGAlZBRDu8S8t35nsN64xoJdMY+fi5MrLE5Q== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1683925644; 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: references:references; bh=PMK22/HxoxSZKsTx+MtkiiSihvL00YPGs/TFPEL6TlU=; b=6Ab3fDB1sVd28x5lyL9nkWKGbymDr5R+6KRuErqPsWXwifdYJwrujMAzLpyfU/ZQhUUikY XNL6casob2M1EbBA== From: Thomas Gleixner To: LKML Cc: x86@kernel.org, David Woodhouse , Andrew Cooper , Brian Gerst , Arjan van de Veen , Paolo Bonzini , Paul McKenney , Tom Lendacky , Sean Christopherson , Oleksandr Natalenko , Paul Menzel , "Guilherme G. Piccoli" , Piotr Gorski , Usama Arif , Juergen Gross , Boris Ostrovsky , xen-devel@lists.xenproject.org, Russell King , Arnd Bergmann , linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Guo Ren , linux-csky@vger.kernel.org, Thomas Bogendoerfer , linux-mips@vger.kernel.org, "James E.J. Bottomley" , Helge Deller , linux-parisc@vger.kernel.org, Paul Walmsley , Palmer Dabbelt , linux-riscv@lists.infradead.org, Mark Rutland , Sabin Rapan , "Michael Kelley (LINUX)" , Ross Philipson Subject: [patch V4 17/37] x86/xen/smp_pv: Remove wait for CPU online References: <20230512203426.452963764@linutronix.de> MIME-Version: 1.0 Date: Fri, 12 May 2023 23:07:24 +0200 (CEST) X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED 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?1765724774626114220?= X-GMAIL-MSGID: =?utf-8?q?1765724774626114220?= From: Thomas Gleixner Now that the core code drops sparse_irq_lock after the idle thread synchronized, it's pointless to wait for the AP to mark itself online. Whether the control CPU runs in a wait loop or sleeps in the core code waiting for the online operation to complete makes no difference. Signed-off-by: Thomas Gleixner Tested-by: Michael Kelley --- arch/x86/xen/smp_pv.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/arch/x86/xen/smp_pv.c +++ b/arch/x86/xen/smp_pv.c @@ -340,11 +340,11 @@ static int xen_pv_cpu_up(unsigned int cp xen_pmu_init(cpu); - rc = HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL); - BUG_ON(rc); - - while (cpu_report_state(cpu) != CPU_ONLINE) - HYPERVISOR_sched_op(SCHEDOP_yield, NULL); + /* + * Why is this a BUG? If the hypercall fails then everything can be + * rolled back, no? + */ + BUG_ON(HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL)); return 0; }