From patchwork Fri Apr 14 23:44:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 13212085 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 47B76C77B79 for ; Fri, 14 Apr 2023 23:44:53 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.521282.809879 (Exim 4.92) (envelope-from ) id 1pnT5w-0006bQ-NE; Fri, 14 Apr 2023 23:44:44 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 521282.809879; Fri, 14 Apr 2023 23:44:44 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1pnT5w-0006Zl-Ap; Fri, 14 Apr 2023 23:44:44 +0000 Received: by outflank-mailman (input) for mailman id 521282; Fri, 14 Apr 2023 23:44:42 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1pnT5t-0000zb-Ls for xen-devel@lists.xenproject.org; Fri, 14 Apr 2023 23:44:41 +0000 Received: from galois.linutronix.de (galois.linutronix.de [193.142.43.55]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 52adff75-db1e-11ed-8611-37d641c3527e; Sat, 15 Apr 2023 01:44:40 +0200 (CEST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 52adff75-db1e-11ed-8611-37d641c3527e Message-ID: <20230414232310.194293270@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1681515880; 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=U86WQCD4/7f+Xqtkcp8tab/f3Qs5fwP9mDOYJzY6GfM=; b=jVIvfWfMQ/Mv7TLWicCCZIBuoCNHTQbWP9agDzTG7YCSq254hUFkclQNrmhW3hMxwO6BPK vpCyMRIt4O1v+XPm4hgw1E/lo8bQ+TLMoWfNV6id2wkbLsusQC6+QgLxHkmM7jqI5M1i8u WMWTwhPBiMRMlROawAHv6lnZ2lJwgt69Ha2d7Hel7C6kpu8UPNf7d9bEsHq2W4HMj8o6m6 dmaviMmKfYNuICvE6NIhMG4fkMK+1VZcm9tvKGIXKcaFCzlTUjXnuorDCoZhFXx/Hy5zi8 WucVMkf4GaCQOYOvuAmNqRgA5o2nLyY6ILSN9/5KO2/baOF9ZKuCj7IpPwPGyQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1681515880; 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=U86WQCD4/7f+Xqtkcp8tab/f3Qs5fwP9mDOYJzY6GfM=; b=bwxgSYDBNDOQrQ9qYJjd5x62eInfveDh14CbqLzga+9pzOoPfQod/ugWmc+ORstEOs2az4 q8XHnTNdR1jM1HBA== 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 , Juergen Gross , Boris Ostrovsky , xen-devel@lists.xenproject.org, David Woodhouse , Usama Arif , 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 Subject: [patch 16/37] x86/xen/smp_pv: Remove wait for CPU online References: <20230414225551.858160935@linutronix.de> MIME-Version: 1.0 Date: Sat, 15 Apr 2023 01:44:39 +0200 (CEST) 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 Cc: Juergen Gross Cc: Boris Ostrovsky Cc: xen-devel@lists.xenproject.org --- 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; }