From patchwork Wed Jan 6 15:39:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 12001909 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84E4CC433DB for ; Wed, 6 Jan 2021 15:41:11 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 32EFF2310D for ; Wed, 6 Jan 2021 15:41:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 32EFF2310D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.62542.110833 (Exim 4.92) (envelope-from ) id 1kxAvi-00053a-JM; Wed, 06 Jan 2021 15:40:58 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 62542.110833; Wed, 06 Jan 2021 15:40:58 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kxAvi-00053T-G8; Wed, 06 Jan 2021 15:40:58 +0000 Received: by outflank-mailman (input) for mailman id 62542; Wed, 06 Jan 2021 15:40:57 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kxAvg-00053E-Oo for xen-devel@lists.xenproject.org; Wed, 06 Jan 2021 15:40:57 +0000 Received: from casper.infradead.org (unknown [2001:8b0:10b:1236::1]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id cbd27039-577d-47b8-bc4e-cf82eb718671; Wed, 06 Jan 2021 15:40:52 +0000 (UTC) Received: from i7.infradead.org ([2001:8b0:10b:1:21e:67ff:fecb:7a92]) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1kxAun-002TH3-UZ; Wed, 06 Jan 2021 15:40:12 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1kxAul-002S24-Vg; Wed, 06 Jan 2021 15:39:59 +0000 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 X-Inumbo-ID: cbd27039-577d-47b8-bc4e-cf82eb718671 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc: To:From:Reply-To:Content-ID:Content-Description; bh=Y4zmIg7u/h9MHqeM4gjTkQQySHu05FosItAdEAKmRis=; b=qGAARmwhcj+AAloiCXr5Yjllfv FUIYUZr7yMoPkn4NdghbWbEz739G43uhzwRaSm2OH4/4NrqYw7uolI1TUAqChsKM0Id5qC6JlytUP zm6yNvgjkddr/+mWXwnD3JRkJ7VyxifeuTT0dRZiliinmg4RZ7emw9KTbuZKEWgUYbPabhELmhuD3 7W0lQy4Bw9JVoCasS+ux2qwABVhWCUoN//EuSHbVw2tLgfu+Hj9vaWGWW2rt7+m34+MyNRYf6e6A2 /tKKYOpA0G/2lxbu8YbvcAYDdWxC9OACTQ6XZKlKE446zSIG7tqNcNH8lRrqTM8MsndF9D1dilRom N6/WbdfQ==; From: David Woodhouse To: x86@kernel.org Cc: Stefano Stabellini , Boris Ostrovsky , Juergen Gross , Paul Durrant , jgrall@amazon.com, karahmed@amazon.de, xen-devel Subject: [PATCH v3 5/5] x86/xen: Fix xen_hvm_smp_init() when vector callback not available Date: Wed, 6 Jan 2021 15:39:58 +0000 Message-Id: <20210106153958.584169-6-dwmw2@infradead.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210106153958.584169-1-dwmw2@infradead.org> References: <20210106153958.584169-1-dwmw2@infradead.org> MIME-Version: 1.0 Sender: David Woodhouse X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html From: David Woodhouse Only the IPI-related functions in the smp_ops should be conditional on the vector callback being available. The rest should still happen: • xen_hvm_smp_prepare_boot_cpu() This function does two things, both of which should still happen if there is no vector callback support. The call to xen_vcpu_setup() for vCPU0 should still happen as it just sets up the vcpu_info for CPU0. That does happen for the secondary vCPUs too, from xen_cpu_up_prepare_hvm(). The second thing it does is call xen_init_spinlocks(), which perhaps counter-intuitively should *also* still be happening in the case without vector callbacks, so that it can clear its local xen_pvspin flag and disable the virt_spin_lock_key accordingly. Checking xen_have_vector_callback in xen_init_spinlocks() itself would affect PV guests, so set the global nopvspin flag in xen_hvm_smp_init() instead, when vector callbacks aren't available. • xen_hvm_smp_prepare_cpus() This does some IPI-related setup by calling xen_smp_intr_init() and xen_init_lock_cpu(), which can be made conditional. And it sets the xen_vcpu_id to XEN_VCPU_ID_INVALID for all possible CPUS, which does need to happen. • xen_smp_cpus_done() This offlines any vCPUs which doesn't fit in the global shared_info page, if separate vcpu_info placement isn't available. That part also needs to happen regardless of vector callback support. • xen_hvm_cpu_die() This doesn't actually do anything other than commin_cpu_die() right right now in the !vector_callback case; all three teardown functions it calls should be no-ops. But to guard against future regressions it's useful to call it anyway, and for it to explicitly check for xen_have_vector_callback before calling those additional functions. Signed-off-by: David Woodhouse Reviewed-by: Boris Ostrovsky --- arch/x86/xen/smp_hvm.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/arch/x86/xen/smp_hvm.c b/arch/x86/xen/smp_hvm.c index f5e7db4f82ab..056430a1080b 100644 --- a/arch/x86/xen/smp_hvm.c +++ b/arch/x86/xen/smp_hvm.c @@ -33,9 +33,11 @@ static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus) int cpu; native_smp_prepare_cpus(max_cpus); - WARN_ON(xen_smp_intr_init(0)); - xen_init_lock_cpu(0); + if (xen_have_vector_callback) { + WARN_ON(xen_smp_intr_init(0)); + xen_init_lock_cpu(0); + } for_each_possible_cpu(cpu) { if (cpu == 0) @@ -50,9 +52,11 @@ static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus) static void xen_hvm_cpu_die(unsigned int cpu) { if (common_cpu_die(cpu) == 0) { - xen_smp_intr_free(cpu); - xen_uninit_lock_cpu(cpu); - xen_teardown_timer(cpu); + if (xen_have_vector_callback) { + xen_smp_intr_free(cpu); + xen_uninit_lock_cpu(cpu); + xen_teardown_timer(cpu); + } } } #else @@ -64,14 +68,17 @@ static void xen_hvm_cpu_die(unsigned int cpu) void __init xen_hvm_smp_init(void) { - if (!xen_have_vector_callback) + smp_ops.smp_prepare_boot_cpu = xen_hvm_smp_prepare_boot_cpu; + smp_ops.smp_prepare_cpus = xen_hvm_smp_prepare_cpus; + smp_ops.smp_cpus_done = xen_smp_cpus_done; + smp_ops.cpu_die = xen_hvm_cpu_die; + + if (!xen_have_vector_callback) { + nopvspin = true; return; + } - smp_ops.smp_prepare_cpus = xen_hvm_smp_prepare_cpus; smp_ops.smp_send_reschedule = xen_smp_send_reschedule; - smp_ops.cpu_die = xen_hvm_cpu_die; smp_ops.send_call_func_ipi = xen_smp_send_call_function_ipi; smp_ops.send_call_func_single_ipi = xen_smp_send_call_function_single_ipi; - smp_ops.smp_prepare_boot_cpu = xen_hvm_smp_prepare_boot_cpu; - smp_ops.smp_cpus_done = xen_smp_cpus_done; }