From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03918C433EF for ; Wed, 15 Dec 2021 13:24:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242827AbhLONYf (ORCPT ); Wed, 15 Dec 2021 08:24:35 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:49720 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237399AbhLONYe (ORCPT ); Wed, 15 Dec 2021 08:24:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1639574674; 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=faX0xzTuw4r5Ss1p1Z66O3C+rjUZMW4qDeU2/6j1vvQ=; b=B0tBW3Iv4VJi6HafhbAT2cNrO+1o1JkbEZeU86ah7IK/KSPLo13Nl7CbuHXcHLUpVqKslH +iiG+SWpPlbb7EFHFG5wEIrvsZYwkk4jv8LVU1YEYq609Cv6+lnaRhAsigB0vZT6m+DrSO L2YDG4ZWaG2ur0iRwmOOrE0VQZskDYU= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-280-h-eYk1FxOqCAGHnfQ4QRlQ-1; Wed, 15 Dec 2021 08:24:33 -0500 X-MC-Unique: h-eYk1FxOqCAGHnfQ4QRlQ-1 Received: by mail-wr1-f70.google.com with SMTP id v18-20020a5d5912000000b001815910d2c0so5916704wrd.1 for ; Wed, 15 Dec 2021 05:24:33 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:organization:in-reply-to :content-transfer-encoding; bh=faX0xzTuw4r5Ss1p1Z66O3C+rjUZMW4qDeU2/6j1vvQ=; b=MHwvBSW+2vtxRfP7ODYebf/4enUAIDaAV6HNVE1MUjf53SS4M6iJ5q+r3nJp0YhPyQ lypMLK7xbY9dqdL1GwgLHJ3ruN8Oyxsg5j9UuZkJT0atluNHr4/cwz072YapYo0LadII hYgqY+n3nA3WjTe3QZKmrWgeqqIiVoS57RPSDotTweiZeWfXXNgkzNPNzqmvgOyHXeBg KveaTktb+sbndw19cX3kUep6bstLAPl6oROHRAnhNS86DIjZs2P6wpCmmrENZRYfjv8F lKFUWMuiJn5ODGNEpFzKZURVcl3vGGre9MYkq7/oOgF6pC2orIz7Zd0/dIdAkYIK58fT NLLw== X-Gm-Message-State: AOAM532jWX7WN9Haga/0hPlfekxe0drtedNvVV6g2n85iUPaXrJ3R97n +Z24JpE1rVI0NTG+maTtat/JUbQe+ScGycS7SuOyW3EATE9snKXXl2t+LyiAOi1TwckHMNUnUzA QkvhzlUGv1flYZr80hUK8Rg== X-Received: by 2002:a5d:4e92:: with SMTP id e18mr4477449wru.89.1639574672098; Wed, 15 Dec 2021 05:24:32 -0800 (PST) X-Google-Smtp-Source: ABdhPJxvYE115YTEnXyOnYw+6M9nPcYQcDwa5GAYcHppd/Ruc2VVaVYWw55fHwyFOHuOPUuAyhomuw== X-Received: by 2002:a5d:4e92:: with SMTP id e18mr4477429wru.89.1639574671898; Wed, 15 Dec 2021 05:24:31 -0800 (PST) Received: from [192.168.3.132] (p5b0c609b.dip0.t-ipconnect.de. [91.12.96.155]) by smtp.gmail.com with ESMTPSA id b132sm1894704wmd.38.2021.12.15.05.24.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 15 Dec 2021 05:24:31 -0800 (PST) Message-ID: <3832e4ab-ffb7-3389-908d-99225ccea038@redhat.com> Date: Wed, 15 Dec 2021 14:24:30 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [RFC PATCH v5 1/1] KVM: s390: Clarify SIGP orders versus STOP/RESTART Content-Language: en-US To: Eric Farman , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Thomas Huth Cc: Heiko Carstens , Vasily Gorbik , kvm@vger.kernel.org, linux-s390@vger.kernel.org References: <20211213210550.856213-1-farman@linux.ibm.com> <20211213210550.856213-2-farman@linux.ibm.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20211213210550.856213-2-farman@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org On 13.12.21 22:05, Eric Farman wrote: > With KVM_CAP_S390_USER_SIGP, there are only five Signal Processor > orders (CONDITIONAL EMERGENCY SIGNAL, EMERGENCY SIGNAL, EXTERNAL CALL, > SENSE, and SENSE RUNNING STATUS) which are intended for frequent use > and thus are processed in-kernel. The remainder are sent to userspace > with the KVM_CAP_S390_USER_SIGP capability. Of those, three orders > (RESTART, STOP, and STOP AND STORE STATUS) have the potential to > inject work back into the kernel, and thus are asynchronous. > > Let's look for those pending IRQs when processing one of the in-kernel > SIGP orders, and return BUSY (CC2) if one is in process. This is in > agreement with the Principles of Operation, which states that only one > order can be "active" on a CPU at a time. > > Suggested-by: David Hildenbrand > Signed-off-by: Eric Farman > --- In general, LGTM. As raised, with SIGP RESTART there are other cases we could fix in the kernel, but they are of very low priority IMHO. -- Thanks, David / dhildenb