From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8E0861C302E for ; Mon, 14 Oct 2024 19:35:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728934535; cv=none; b=XN6R/EGHj5yqvd0fdnT37tHL/UVkZaqJqOhDPv64Atts7cVbV4AjlKBHUk2u4NFcZ/9obsrDId2GTgd+qIPbenssUB9l9WivrqEyfuMyTAPRtXFdoGq83/WfMlIJGN+maO0a4goib2thN70r9OXShd6+5DSBqY6Rj5gr/Ne7fOQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728934535; c=relaxed/simple; bh=ATb9FQ16x78hfIMSaPpd+FQuWIsSjOLL9lHPFZfzluE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=imCPToYbO8YP7Nf4vu5ZMYoPj0cCkrI4W1aM27ZCeeBNxBIYrg+VV2lxKCQVWl9vcrzsfFJpdzZa6eRN+2cy7TGY7t/CHUngEVIsAX9gCo2qNQ+kYfQyjydqrq7QHCsx2paYXcrwxfoiqum3mJCh7i5LcFrSejytvA3iT+Ubc74= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=EeWx1pNG; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="EeWx1pNG" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1728934532; 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:autocrypt:autocrypt; bh=sgEXWzSvIwubbV7unridAoQa4cdce3CR6+dDgB9+5yc=; b=EeWx1pNGp4aX6px7r2Sm9UnAXG1CYOAYv7yVeazGYVO6ApfUezqf3piNvZWbLvA2knZosA K4Fqv9r8ZvdvdNH6LwcjFfYh7gb2sCx9EGFwCHbtonc18BjSTXxqvshZKpCJCTwFa1ShgD e9kV0gzAZj8WxuIAu8G1Kr6H6KB/Omo= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-394-DYd5icGwOR-4iqYqksmvKg-1; Mon, 14 Oct 2024 15:35:31 -0400 X-MC-Unique: DYd5icGwOR-4iqYqksmvKg-1 Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-37d67f4bf98so1083471f8f.1 for ; Mon, 14 Oct 2024 12:35:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728934530; x=1729539330; h=content-transfer-encoding:in-reply-to:organization:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=sgEXWzSvIwubbV7unridAoQa4cdce3CR6+dDgB9+5yc=; b=NQuE0nl877vSSwLDfYCohZJnjlGxXhMJL9ilIGEEDunMiW31vGp1w2VMGl7MW0UhSm bFbNJbrpNSF7nqguwuy7kugmTWMDx6KjwnIVqEz0bjwEtgH1rf5QEQUT13uyq+5c+FdW YqDfKpg/eMp/KtxHnUKwZva1e0KeHL/djuHecQHCwb90yBmzDSJbeFA/UKrbkjVdhaB9 6CBQAkBXPnfRXN8BaK7+VeA4YlzNFemRgWT8qZDIkaEEXZ1iRN7HNwrpejKKcdh9hV/r ZBlDEzkwD92+jRSEiTpYE9fMK7VZ3NZFFzHYh4sCQBb2ueXOnHbV08adLjL4TSeE/r35 9y8Q== X-Gm-Message-State: AOJu0Ywb5IubmA9QLjfy0lXIRIKYJ8U/BWNHvRn5IHsDKYFRInMnicq+ T868fiT1jRd+sFsTeuCyowy1Pth3APdmXxQBjra5CVhXqJVy+dccJw2ZX4JDcc4WpENVta1T7mM LiUVCn7vNxEOFSHWAuYmT/t1q3uuaeveg6MWo/jRMPUvJB5kvC+s2zMhUIICt8g== X-Received: by 2002:adf:f98a:0:b0:37c:ce58:5a1a with SMTP id ffacd0b85a97d-37d552d22efmr8719168f8f.54.1728934529929; Mon, 14 Oct 2024 12:35:29 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGmLVPlsR53bsF9ZXTvVKgUGcOHdy2gZRmudwBVh0AEj48pcH21cjEcwhpIbdusHD2n/ntBeg== X-Received: by 2002:adf:f98a:0:b0:37c:ce58:5a1a with SMTP id ffacd0b85a97d-37d552d22efmr8719138f8f.54.1728934529506; Mon, 14 Oct 2024 12:35:29 -0700 (PDT) Received: from ?IPV6:2003:cb:c71e:600:9fbb:f0bf:d958:5c70? (p200300cbc71e06009fbbf0bfd9585c70.dip0.t-ipconnect.de. [2003:cb:c71e:600:9fbb:f0bf:d958:5c70]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-430ccf1f776sm163003415e9.3.2024.10.14.12.35.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 14 Oct 2024 12:35:29 -0700 (PDT) Message-ID: <78e8794a-d89f-4ded-b102-afc7cea20d1d@redhat.com> Date: Mon, 14 Oct 2024 21:35:27 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/7] Documentation: s390-diag.rst: make diag500 a generic KVM hypercall To: Heiko Carstens Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-s390@vger.kernel.org, virtualization@lists.linux.dev, linux-doc@vger.kernel.org, kvm@vger.kernel.org, Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Thomas Huth , Cornelia Huck , Janosch Frank , Claudio Imbrenda , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?Q?Eugenio_P=C3=A9rez?= , Andrew Morton , Jonathan Corbet References: <20241014144622.876731-1-david@redhat.com> <20241014144622.876731-3-david@redhat.com> <20241014180410.10447-C-hca@linux.ibm.com> Content-Language: en-US From: David Hildenbrand Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <20241014180410.10447-C-hca@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 14.10.24 20:04, Heiko Carstens wrote: > On Mon, Oct 14, 2024 at 04:46:14PM +0200, David Hildenbrand wrote: >> Let's make it a generic KVM hypercall, allowing other subfunctions to >> be more independent of virtio. >> >> This is a preparation for documenting a new hypercall. >> >> Signed-off-by: David Hildenbrand >> --- >> Documentation/virt/kvm/s390/s390-diag.rst | 15 ++++++++------- >> 1 file changed, 8 insertions(+), 7 deletions(-) > > ... > >> -DIAGNOSE function code 'X'500' - KVM virtio functions >> ------------------------------------------------------ >> +DIAGNOSE function code 'X'500' - KVM functions >> +---------------------------------------------- >> >> -If the function code specifies 0x500, various virtio-related functions >> -are performed. >> +If the function code specifies 0x500, various KVM-specific functions >> +are performed, including virtio functions. >> >> -General register 1 contains the virtio subfunction code. Supported >> -virtio subfunctions depend on KVM's userspace. Generally, userspace >> -provides either s390-virtio (subcodes 0-2) or virtio-ccw (subcode 3). >> +General register 1 contains the subfunction code. Supported subfunctions >> +depend on KVM's userspace. Regarding virtio subfunctions, generally >> +userspace provides either s390-virtio (subcodes 0-2) or virtio-ccw >> +(subcode 3). > > Reading this file leaves a number of questions open: how does one know > which subcodes are supported, and what happens if an unsupported > subcode is used? Currently they have to be sensed > > I'm afraid there is no indication available and the only way to figure > out is to try and if it is unsupported the result is a specification > exception. Is that correct? Yes exactly. > > If so, it would be nice to document that too; but that is not > necessarily your problem. I can squash: diff --git a/Documentation/virt/kvm/s390/s390-diag.rst b/Documentation/virt/kvm/s390/s390-diag.rst index d9b7c6cbc99e..48a326d41cc0 100644 --- a/Documentation/virt/kvm/s390/s390-diag.rst +++ b/Documentation/virt/kvm/s390/s390-diag.rst @@ -50,6 +50,9 @@ Upon completion of the DIAGNOSE instruction, general register 2 contains the function's return code, which is either a return code or a subcode specific value. +If the specified subfunction is not supported, a SPECIFICATION exception +will be triggered. + Subcode 0 - s390-virtio notification and early console printk Handled by userspace. > > I guess we won't see too many new diag 500 subcodes, or would it make > sense to implement some query subcode? In the context of STORAGE LIMIT, a "query" subfunction is not really beneficial: it's either one invocation of "query", conditionally followed by one invocation of "STORAGE LIMIT" vs. one invocation of "STORAGE LIMIT". Once there might be a bunch of other subfunctions, a "query" might make more sense. Thanks! -- Cheers, David / dhildenb