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: 13212152 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 3BA3EC77B72 for ; Fri, 14 Apr 2023 23:47:37 +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=eYUI7FxXvgEYIWTndZIobLk6jSHv8kMG3nnx+xUm3gA=; b=HUUIRTE1Z5BvLN d8BHNDuVluNkndbMkpYiOOlh8b6295eAotd5FD4sah1uDU43r9wMYVGENlyIVOm97wwOymm8Zxk+t yQnvSTdeBJ4UDhZ6plzsY2AnJw98HFh5xCocPMIu/YqqCxIF9DpMnnTM7pUByCBpLfO/mCd0dVAks sdryE7ro5rD00UY+vvWkOYvq/A/HwEqTX8ssm+FsazIJjIgCTAxmFmA9zGpYqOpUcCWTb13875Wc4 8om8o0D1qKz7cWbLdGV0ZnII6JptLbA60kE2ov8Wsv29dHsIAj9v3sIhYsXnzIfbjFygGSlloP14a /N41CCfN8qd9RBT/IMuw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pnT7n-00AlvT-1R; Fri, 14 Apr 2023 23:46:39 +0000 Received: from galois.linutronix.de ([2a0a:51c0:0:12e:550::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pnT5t-00AkFp-1C; Fri, 14 Apr 2023 23:44:42 +0000 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) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230414_164441_568795_9723E77E X-CRM114-Status: GOOD ( 11.40 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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; }