From patchwork Mon May 8 19:43:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 13234897 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 3A97EC7EE24 for ; Mon, 8 May 2023 19:44:42 +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=lx8AfY7bhjaZP0M+y1gIy1fmGCnKvBN+qB7gfwz57EM=; b=XMPWpekLqACceK FBikOoc7hG+nocC3tr7LP2YGHhBRaoWROTeb70nA4LolgpPxDGZE5mfjzzZr/t8gYwkj8kJr9Rk/5 gxCFRiIY8qsXN4AsUo81jNR+mv9JopDL9A2Wk7Q9D2pdROSI/EucogYSnc9GYMFwBHPDE6CBaFEss XkGb3GlbTqPUdqiQbTyjN/jewS7yxeTls0cMQkTkbAEs5MDFI9UQHruT12UvXm0uQvAL5McK5XFVq bPInmBG4rtTs35MlNni5KIjQZrIRw29jle+DgemkX5P75mWyAxcYuXpQV9v9vpTp3M3jjOT94KKy1 zeF7KIr6t7uZeRYa/hYw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pw6mf-001EyN-1J; Mon, 08 May 2023 19:44:33 +0000 Received: from galois.linutronix.de ([193.142.43.55]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pw6m2-001EEm-1w; Mon, 08 May 2023 19:44:09 +0000 Message-ID: <20230508185218.127315637@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1683575033; 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=3mTnL+eNa5W0nTjOIkPEr4xfOzLcS1B04oILYIrEMyg=; b=eXpNMch9880MTyH+0Fz++N2mu/WFctp1eVVZZiPgiFCXMrCyTDadzskT0l9z0ZwlHcQvpi 9kOXC1Ff+g7cp+JCq8d1S0oE842eFc1UxgDKQQeOqkarfCqFbRshssa2KqOorq+nJ88tDD fEwDRj+DjeBHMdKLi4HMvK6U1AZG5K1eaPpGnaB41VL5++7xyatSf8XaejDnLahfRNMaFZ tRdTESS436fnKAXT9YC2WSG2YnfEsRaEZ1La5POAwvfbErvcr0mQIh0UqhWVl9XCwRW6hl L0VvqXarQ/4OtLm/Xar1BiBIJIO4YV8immaktE8lAUNSC0Bjdpx+QwPKR8ozZQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1683575033; 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=3mTnL+eNa5W0nTjOIkPEr4xfOzLcS1B04oILYIrEMyg=; b=cOcWhFITcchL8q9j8XJqY4yP565IAGOCYm0IG0oNwqVPTKDJpWdAXEM1GM1oNZ+wZdo+zX mjuMRPU8QuqrdVDQ== 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)" Subject: [patch v3 16/36] x86/xen/smp_pv: Remove wait for CPU online References: <20230508181633.089804905@linutronix.de> MIME-Version: 1.0 Date: Mon, 8 May 2023 21:43:52 +0200 (CEST) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230508_124354_851488_CDCBD614 X-CRM114-Status: GOOD ( 13.03 ) 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; }