From patchwork Tue Jan 16 18:26:57 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vitaly Kuznetsov X-Patchwork-Id: 10167889 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A735F601E7 for ; Tue, 16 Jan 2018 18:30:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A2B6A262FF for ; Tue, 16 Jan 2018 18:30:19 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9732726538; Tue, 16 Jan 2018 18:30:19 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4ED13262FF for ; Tue, 16 Jan 2018 18:30:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751681AbeAPS17 (ORCPT ); Tue, 16 Jan 2018 13:27:59 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48764 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750868AbeAPS1z (ORCPT ); Tue, 16 Jan 2018 13:27:55 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 86903C01B3E7; Tue, 16 Jan 2018 18:27:45 +0000 (UTC) Received: from vitty.brq.redhat.com (unknown [10.43.2.155]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5F21C600D2; Tue, 16 Jan 2018 18:27:35 +0000 (UTC) From: Vitaly Kuznetsov To: kvm@vger.kernel.org, x86@kernel.org Cc: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "K. Y. Srinivasan" , Haiyang Zhang , Stephen Hemminger , "Michael Kelley (EOSG)" , Andy Lutomirski , Mohammed Gamal , Cathy Avery , Roman Kagan , linux-kernel@vger.kernel.org, devel@linuxdriverproject.org Subject: [PATCH v3 4/7] x86/hyper-v: redirect reenlightment notifications on CPU offlining Date: Tue, 16 Jan 2018 19:26:57 +0100 Message-Id: <20180116182700.1042-5-vkuznets@redhat.com> In-Reply-To: <20180116182700.1042-1-vkuznets@redhat.com> References: <20180116182700.1042-1-vkuznets@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Tue, 16 Jan 2018 18:27:50 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP It is very unlikely for CPUs to get offlined when we run on Hyper-V as we have a protection in vmbus module which prevents it when we have any VMBus devices assigned. This, however, may change in future if an option to reassign an already active channel will be added. It is also possible to run without any Hyper-V devices of have a CPU with no assigned channels. Reassign reenlightenment notifications to some other active CPU when the CPU which is assigned to get them goes offline. Signed-off-by: Vitaly Kuznetsov Reviewed-by: Thomas Gleixner --- v2-> v3: - Drop spinlock protection from hv_cpu_die() as cpu hotplug is already serialized [Thomas Gleixner] - Use cpumask_any_but() in hv_cpu_die() [Thomas Gleixner] --- arch/x86/hyperv/hv_init.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 712ac40081f7..e4377e2f2a10 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -191,6 +191,26 @@ void clear_hv_tscchange_cb(void) } EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb); +static int hv_cpu_die(unsigned int cpu) +{ + struct hv_reenlightenment_control re_ctrl; + unsigned int new_cpu; + + if (hv_reenlightenment_cb == NULL) + return 0; + + rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl)); + if (re_ctrl.target_vp == hv_vp_index[cpu]) { + /* Reassign to some other online CPU */ + new_cpu = cpumask_any_but(cpu_online_mask, cpu); + + re_ctrl.target_vp = hv_vp_index[new_cpu]; + wrmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl)); + } + + return 0; +} + /* * This function is to be invoked early in the boot sequence after the * hypervisor has been detected. @@ -220,7 +240,7 @@ void hyperv_init(void) return; if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online", - hv_cpu_init, NULL) < 0) + hv_cpu_init, hv_cpu_die) < 0) goto free_vp_index; /*