From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) by mx.groups.io with SMTP id smtpd.web09.1363.1608580649715670034 for ; Mon, 21 Dec 2020 11:57:29 -0800 Authentication-Results: mx.groups.io; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=hy88iHTH; spf=pass (domain: redhat.com, ip: 63.128.21.124, mailfrom: lersek@redhat.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1608580648; 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=BFZQ3H3UmqshT6G51daukh6DAqzzZ3TxT/mZfnWuZlk=; b=hy88iHTHSO+/PQYpx/aSam6aWIagS+auCxHOsq0HkwG22Fgh+J+0prDZoWZvhoROjkoV7G YIgXQK+4NjHy5nHw7ge9Px/5PCTJ2rOVSuFoWLLq6bPeHgm9W5WWApKpgW6HNjqxh3xUWq U4FqcdLfJMhaMvNApMzPp4MBAwZ+VwY= 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-484-x6thR560PZO6gZvupWttjA-1; Mon, 21 Dec 2020 14:57:23 -0500 X-MC-Unique: x6thR560PZO6gZvupWttjA-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 03B3818C8C01; Mon, 21 Dec 2020 19:57:22 +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 CFEF417C58; Mon, 21 Dec 2020 19:57:20 +0000 (UTC) Subject: Re: [edk2-devel] [RFC PATCH 0/5] support CPU hot-unplug To: Igor Mammedov Cc: devel@edk2.groups.io, ankur.a.arora@oracle.com, boris.ostrovsky@oracle.com References: <20201208053432.2690694-1-ankur.a.arora@oracle.com> <70e6bf5d-3d59-2e6f-4b5a-2e68cdda8108@redhat.com> <20201221164639.24f83ba4@redhat.com> From: "Laszlo Ersek" Message-ID: <55fac2cb-ea37-e920-d254-6a5e13adda52@redhat.com> Date: Mon, 21 Dec 2020 20:57:19 +0100 MIME-Version: 1.0 In-Reply-To: <20201221164639.24f83ba4@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 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 On 12/21/20 16:46, Igor Mammedov wrote: > On Mon, 21 Dec 2020 15:44:35 +0100 > "Laszlo Ersek" wrote: > >> 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. > BTW: > > meanwhile, QEMU part got merged so one doesn't need to hunt for it anymore. > If something is broken there, we will have to fix it on top. Thank you very much for the info! Laszlo