From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by mx.groups.io with SMTP id smtpd.web09.747.1608561885049077273 for ; Mon, 21 Dec 2020 06:44:47 -0800 Authentication-Results: mx.groups.io; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=dD5itfnK; spf=pass (domain: redhat.com, ip: 216.205.24.124, mailfrom: lersek@redhat.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1608561884; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=r7JVSDfpz/mcWuCH57KGmdo2PZ1izOG7DcsfrSJUPRA=; b=dD5itfnKKXpr3+o9lHeZVak9Kbt8Mb+tEYkP4BwOQQr6wLvthrWelhIO9gR34ZmujExdqc 40Bbj3nlTT7IbcXTOsYzbVwrDKXbfWcVQnaxB3OC2jM/B3Bdix0yF48N0kou4imWw8EM6J 2ryH7kPvGiYMw6oTtC5MdhKpfPDwihs= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-165-23H1lZDkMYqhteSvttWHOA-1; Mon, 21 Dec 2020 09:44:38 -0500 X-MC-Unique: 23H1lZDkMYqhteSvttWHOA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 88F1C100C660; Mon, 21 Dec 2020 14:44:37 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-114-71.ams2.redhat.com [10.36.114.71]) by smtp.corp.redhat.com (Postfix) with ESMTP id 82A0A1002391; Mon, 21 Dec 2020 14:44:36 +0000 (UTC) Subject: Re: [edk2-devel] [RFC PATCH 0/5] support CPU hot-unplug To: devel@edk2.groups.io, ankur.a.arora@oracle.com Cc: imammedo@redhat.com, boris.ostrovsky@oracle.com References: <20201208053432.2690694-1-ankur.a.arora@oracle.com> From: "Laszlo Ersek" Message-ID: <70e6bf5d-3d59-2e6f-4b5a-2e68cdda8108@redhat.com> Date: Mon, 21 Dec 2020 15:44:35 +0100 MIME-Version: 1.0 In-Reply-To: <20201208053432.2690694-1-ankur.a.arora@oracle.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=lersek@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Hi Ankur, On 12/08/20 06:34, Ankur Arora wrote: > [ Resending to the correct edk2 alias this time. ] > > Hi, > > This series adds support for CPU hot-unplug with OVMF. > > Please see this in conjunction with the QEMU v2 series posted here: > https://lore.kernel.org/qemu-devel/20201207140739.3829993-1-imammedo@redhat.com/ > > In particular, would be glad for comments on Patch 4, specifically > where we should be ejecting the CPU. > > Right now the ejection happens in UnplugCpus() (called from > CpuHotplugMmi()): > + QemuCpuhpWriteCpuSelector (mMmCpuIo, RemoveApicId); > + QemuCpuhpWriteCpuStatus (mMmCpuIo, QEMU_CPUHP_STAT_EJECTED); > > That is way too early -- given that the actual unplug will happen > in SmmCpuUpdate() and given that the BSPHandler() would have waited > for the APs multiple times before then. > > Another possibility is that the actual ejection be deferred to the > _EJ0 method after the return from the SMI. But, that seems like a > hack. Additionally, Igor points out here that this approach has problems: > https://lore.kernel.org/qemu-devel/20201204170939.1815522-1-imammedo@redhat.com/ I've filed: https://bugzilla.tianocore.org/show_bug.cgi?id=3132 Can you please register an account in the TianoCore Bugzilla at , and assign the above ticket to yourself? And then, the URL of the new BZ ticket should be included in every commit message, like this: Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3132 just above your S-o-b. No need to repost just because of this; I'll review the RFC series later. Thanks, Laszlo > > Please review. > > Thanks > Ankur > > Ankur Arora (5): > OvmfPkg/CpuHotplugSmm: move CPU Hotplug into PlugCpus() > OvmfPkg/CpuHotplugSmm: handle fw_remove > OvmfPkg/CpuHotplugSmm: add CpuStatus helper function > OvmfPkg/CpuHotplugSmm: handle CPU hot-unplug > OvmfPkg/SmmControl2Dxe: negotiate ICH9_LPC_SMI_F_CPU_HOT_UNPLUG > > OvmfPkg/CpuHotplugSmm/CpuHotplug.c | 293 ++++++++++++------ > OvmfPkg/CpuHotplugSmm/QemuCpuhp.c | 58 +++- > OvmfPkg/CpuHotplugSmm/QemuCpuhp.h | 6 + > .../Include/IndustryStandard/QemuCpuHotplug.h | 2 + > OvmfPkg/SmmControl2Dxe/SmiFeatures.c | 21 +- > 5 files changed, 280 insertions(+), 100 deletions(-) >