From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by mx.groups.io with SMTP id smtpd.web11.195023.1673959028426415251 for ; Tue, 17 Jan 2023 04:37:08 -0800 Authentication-Results: mx.groups.io; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=VX7CUskm; spf=pass (domain: redhat.com, ip: 170.10.129.124, mailfrom: kraxel@redhat.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673959027; 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: in-reply-to:in-reply-to:references:references; bh=G4Eak6U1jpGAbWMMzVtmAE+MEKscQsnBdsdPQe4gBAc=; b=VX7CUskmnUKMN5TDeQHluAmV2lVK3SkzcD6lhxldkVG2EFr3Sl2rI0GVxudPL/BdVHOB0V ki1oV8dfGbb1Nbf/ZCqPZpjaUQjhRSXgpOdBeWJAfcXyZBlUCT1TEQtufHJEvBlxKZJBip 3+zo44oASURpW2dXJ89pyBqGKa/Kvj4= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-621-fRmk6CpUNfm1ItNUN_WLSg-1; Tue, 17 Jan 2023 07:37:04 -0500 X-MC-Unique: fRmk6CpUNfm1ItNUN_WLSg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 86B5D882821; Tue, 17 Jan 2023 12:37:03 +0000 (UTC) Received: from sirius.home.kraxel.org (unknown [10.39.192.124]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E7FDF2026D68; Tue, 17 Jan 2023 12:37:02 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 379A91800097; Tue, 17 Jan 2023 13:37:00 +0100 (CET) Date: Tue, 17 Jan 2023 13:37:00 +0100 From: "Gerd Hoffmann" To: Laszlo Ersek Cc: devel@edk2.groups.io, Michael Brown , Ard Biesheuvel , Brijesh Singh , Erdem Aktas , James Bottomley , Jiewen Yao , Jordan Justen , Min Xu , Oliver Steffen , Sebastien Boeuf , Tom Lendacky Subject: Re: [edk2-devel] [PATCH v2] OvmfPkg/PlatformInitLib: catch QEMU's CPU hotplug reg block regression Message-ID: <20230117123700.ntg5fk7a3ggr2xyo@sirius.home.kraxel.org> References: <20230112082845.128463-1-lersek@redhat.com> <01020185a568604c-e16d8581-963a-4ff3-8566-bf0640ad327d-000000@eu-west-1.amazonses.com> <407c5cee-7a6c-cbc8-35cc-8f2c2724914c@redhat.com> <01020185a6bda78a-05d82180-4d1a-4af4-9a9b-ac78088d11ed-000000@eu-west-1.amazonses.com> <49e4e8bb-3bbd-0ca8-ee59-e75560deffa7@redhat.com> <20230113060354.siony3rjwpgzd5tk@sirius.home.kraxel.org> <20230113093205.oh7euprqlmp26wpu@sirius.home.kraxel.org> <20230113122246.uabdhut4ziwerivm@sirius.home.kraxel.org> <9141ad66-f868-762c-7ea5-d88753466fa6@redhat.com> MIME-Version: 1.0 In-Reply-To: <9141ad66-f868-762c-7ea5-d88753466fa6@redhat.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi, > >> In particular the firmware makes no further decisions based on > >> whether QEMU advertized some of these features. > > > > I was thinking the other way around: When cpu hotplug is disabled in > > qemu it should be safe to skip the whole cpu hotplug checking dance. > > See test patch below. > > > > That would give us a config switch (turn off cpu hotplug support) > > which would allow edk2 run on qemu versions with broken cpu hotplug. > > > > Does the idea look sane or do I miss something? > This would be wrong. > > [ detailed description snipped here (but stored for later reference, > thanks for all the details) ] So, the tl;dr version: cpu hotplug is older than smi feature negotiation, so smi hotplug feature bit being off doesn't imply qemu wouldn't hotplug cpus. So, no easy way out. Luckily this affects tcg only. For edk2 ci doing (tcg) efi shell test boots switching to Oliver's latest containers with fixed qemu included should handle things (latest series just posted). So once this is in we should be able to merge this patch without breaking CI. take care, Gerd