From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from a7-11.smtp-out.eu-west-1.amazonses.com (a7-11.smtp-out.eu-west-1.amazonses.com [54.240.7.11]) by mx.groups.io with SMTP id smtpd.web11.59417.1673539727133670928 for ; Thu, 12 Jan 2023 08:08:47 -0800 Authentication-Results: mx.groups.io; dkim=pass header.i=@ipxe.org header.s=cphpx6z2rfcgehlykjjh3gknqe3hsoe2 header.b=fi/pRs4U; spf=pass (domain: eu-west-1.amazonses.com, ip: 54.240.7.11, mailfrom: 01020185a6bda78a-05d82180-4d1a-4af4-9a9b-ac78088d11ed-000000@eu-west-1.amazonses.com) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/simple; s=cphpx6z2rfcgehlykjjh3gknqe3hsoe2; d=ipxe.org; t=1673539725; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From:In-Reply-To:Content-Type:Content-Transfer-Encoding; bh=ck0G7X83ISUzod6dv+X7kPSqCxm5uzEYotUyiZo9qIk=; b=fi/pRs4UX6eJy2HF0D0wEMcXs2QfejeHsHAASod6tZJhHo6wu/eMxoBCLX870D32 xPSfVbwT0HAcYxe0vDSvlCoaFwkKfE0xEP5xxvYgNc3H/OADHeqRnOdlejCulBNNokA ujif/Zgtb/jzS2uf/e+JkQP+hmgPlFPaTgM2lzYzGwMqNwzEiuByKruD8hzbzVTeofT hYCC5tcU6mNS7DrMSr5xLUGyA9kbZpC7Iy8mw1Cn3Iyi9YvW5WfNOFPHTik5DO1nYjR zr26hbvh7djel3jUPNpfEOPwAeC7tzGvU1cinqwsnkZJ6WXNgX3fMG/rga/n5xIk4lH b02cDBSPiQ== DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/simple; s=ihchhvubuqgjsxyuhssfvqohv7z3u4hn; d=amazonses.com; t=1673539725; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From:In-Reply-To:Content-Type:Content-Transfer-Encoding:Feedback-ID; bh=ck0G7X83ISUzod6dv+X7kPSqCxm5uzEYotUyiZo9qIk=; b=d53IWuE8kc+rMEII9z/DHpMBomr0wvJ9qRIf1rykLbgtrTDWIVDPkZFHCtWO6t+r NMBq+tfY3k5hds0vuocOUc+InmuMlyolrqbalf7JGspNZS6+l1prI9qdh401Q/vkQG/ 8JhSNH57Eypw+FXs6TnB5764bOOigSN4e5dyM0tM= Message-ID: <01020185a6bda78a-05d82180-4d1a-4af4-9a9b-ac78088d11ed-000000@eu-west-1.amazonses.com> Date: Thu, 12 Jan 2023 16:08:45 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 Subject: Re: [edk2-devel] [PATCH v2] OvmfPkg/PlatformInitLib: catch QEMU's CPU hotplug reg block regression To: devel@edk2.groups.io, lersek@redhat.com Cc: Ard Biesheuvel , Brijesh Singh , Erdem Aktas , Gerd Hoffmann , James Bottomley , Jiewen Yao , Jordan Justen , Min Xu , Oliver Steffen , Sebastien Boeuf , Tom Lendacky 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> From: "Michael Brown" In-Reply-To: <407c5cee-7a6c-cbc8-35cc-8f2c2724914c@redhat.com> X-Spam-Status: No, score=-2.9 required=5.0 tests=ALL_TRUSTED,BAYES_00 autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on blyat.fensystems.co.uk Feedback-ID: 1.eu-west-1.fspj4M/5bzJ9NLRzJP0PaxRwxrpZqiDQJ1IF94CF2TA=:AmazonSES X-SES-Outgoing: 2023.01.12-54.240.7.11 Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 12/01/2023 13:22, Laszlo Ersek wrote: >>> Detect the issue in PlatformMaxCpuCountInitialization(), and >>> print an error message and *hang* if the issue is present. >> >> Would this mean that OVMF would refuse to start with all current >> distro versions of qemu (when not using KVM), or am I >> misunderstanding? > > Your understanding is correct. I apologise in advance if this is a stupid question, but: given that we can detect the issue (as per this patch), and given also: >> On 12/01/2023 08:28, Laszlo Ersek wrote: >>> In QEMU v5.1.0, the CPU hotplug register block misbehaves: the >>> negotiation protocol is (effectively) broken such that it >>> suggests that switching from the legacy interface to the modern >>> interface works, but in reality the switch never happens. ...would it work to detect the issue and treat it as "modern interface is not supported: continue to use the legacy interface"? IOW, to treat "Present=0" as indicating that the modern interface is not supported. Thanks, Michael