From patchwork Fri May 12 21:07:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 13239769 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CA72AC77B7F for ; Fri, 12 May 2023 21:08:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Date:MIME-Version:References:Subject:Cc :To:From:Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: List-Owner; bh=ITe9I+mB6gosBs4CsIqQ5fJGEwS6n8ts5w21vkHYrwo=; b=hbqCdi9nS/KphA ig6cqOqG0vnXLWN69T2lN4/Lkv9n+b3hBrD31b42i//nmkXi7p60A3WBXGSIpuCDRoJ0J3SIeYzWj i+lav8rH8s89bhUckkVvwAiDcneQnmkqEAgLdpzyoFrTdRBEoQHqXY9voQenbpe/6qj29pM+A3Tnh HaKs7RyCEiqKuBzf3cxhmog7USwXVg4f0KZYK5RrvsT+O+JyVar1AlCCbjHo/ZpWLoiTHPYCL1eUL ZKMnzVkKqXFjpxh9HhSI3d4FzAaOHRxRcGtTu9VQkDPdzDbKpJkY6N7RdtYx1a1mHMf91Kr0Dj86k EzNSVFTN41BLiSL5BMmg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pxa0J-00CzuR-2b; Fri, 12 May 2023 21:08:44 +0000 Received: from galois.linutronix.de ([193.142.43.55]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pxZz4-00CyfB-0l; Fri, 12 May 2023 21:07:27 +0000 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-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230512_140726_460848_9263B3E5 X-CRM114-Status: GOOD ( 12.42 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 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; }