From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 69A2E3A9630; Wed, 2 Sep 2026 08:23:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788337405; cv=none; b=GVKN9JJya24GSNWWpssJS8kbdydO+M8DiJmrWjGDVuimA2AokBu4pL99eJQ2litcZ3LJDCrxCKm6GaNw/xhnDRv8PL9HyHNzCpv5fbrEpXX6Tp/EwPYkl1BiFGr/YDgNV26zB8EdhWpPph7B98zSAt5J4yQMJHZcHHm3hiaXHE8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788337405; c=relaxed/simple; bh=1YA7KrKUXP5X2FofENU2/aXNV6EBmGjLdJ+cT+IxTyQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=KX4lz0+2cK/iI3K2/8rxxWfLMJ8yC9B8i7YFjWgYi+udVNv6cNfQrwJW3rhvEV0nU3596boBpIz6ZUfPmlsFA3fg8TUzFoIbtYi6kaudOHTn1Dwx7+ZEgHdp+g++93eFKJPx9WISapyAIKPPGG2RoM0PPtdTFwvcAfTKxeSIDdQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=n5KMNp2c; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="n5KMNp2c" Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 6826VvZI2306903; Wed, 2 Sep 2026 08:23:04 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=pp1; bh=myq+/DG3jtnOprRIB3t4zbh7K9JqN7 YDUvAzxlH/Waw=; b=n5KMNp2cQl2aqL25b6hN6sJWMAf8b47u9YbUx1H9gd5nK1 jEQUSkO/REmV8QKBiQ9bvH0tJr2Gqs58sUMsvelE0IhAMiHX+ZLL5mOX4RcSrZzP xWzZ/eLFxQm5cW1VeOzrXOkStwYvnaEv0M0gB4vItwG15wj+HcPN7JXOLh9VGgG7 AoH8EmRF54feFpFmhg4SnBLOMIaBL6MDhFwb3SytSzWUyZXtV3Dl6biHPybwpNck g1DRwGJmORxckiWE1RRU5byHPpVapugpdy/2uxlWrp2vEgxNy4EKeKhieopSOJH/ 3OPuAT7N2mioohjMmF945xFalcbZGbA8Ugp+ceyg== Received: from ppma13.dal12v.mail.ibm.com (dd.9e.1632.ip4.static.sl-reverse.com [50.22.158.221]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4gbnudvy9a-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 02 Sep 2026 08:23:03 +0000 (GMT) Received: from pps.filterd (ppma13.dal12v.mail.ibm.com [127.0.0.1]) by ppma13.dal12v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 6828BLQ5012528; Wed, 2 Sep 2026 08:23:02 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma13.dal12v.mail.ibm.com (PPS) with ESMTPS id 4gcbyggdrk-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 02 Sep 2026 08:23:02 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (smtpav04.fra02v.mail.ibm.com [10.20.54.103]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 6828MwmU46334282 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 2 Sep 2026 08:22:58 GMT Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7AE9A2004B; Wed, 2 Sep 2026 08:22:58 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1871720043; Wed, 2 Sep 2026 08:22:58 +0000 (GMT) Received: from osiris (unknown [9.224.76.185]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTPS; Wed, 2 Sep 2026 08:22:58 +0000 (GMT) Date: Wed, 2 Sep 2026 10:22:56 +0200 From: Steffen Eiden To: Sean Christopherson Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, Alexander Gordeev , Andreas Grapentin , Arnd Bergmann , Catalin Marinas , Christian Borntraeger , Claudio Imbrenda , David Hildenbrand , Friedrich Welter , Fuad Tabba , Gautam Gala , Hariharan Mari , Heiko Carstens , Hendrik Brueckner , Ilya Leoshkevich , Janosch Frank , Joey Gouly , Marc Zyngier , Nico Boehr , Nina Schoetterl-Glausch , Oliver Upton , Paolo Bonzini , Suzuki K Poulose , Sven Schnelle , Ulrich Weigand , Vasily Gorbik , Will Deacon , Zenghui Yu Subject: Re: [PATCH v7 03/23] KVM: Allow KVM implementations to switch off MMIO independent of Kconfig Message-ID: <20260902082256.438647-A-seiden@linux.ibm.com> References: <20260831144802.834315-1-seiden@linux.ibm.com> <20260831144802.834315-4-seiden@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-GUID: PegjYO2dcjjFja5IBSIoksPFsA3_yCIF X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTAyMDA3MCBTYWx0ZWRfXxZTpdKIMadP+ hECdMkWYg8VeNfu0AcnLQXTBiCaI3zlfwxdL45awk2mKQnlMZxXf6EFh7Hspz115kooBrW+gcWo OLyn7miU1JZqbCSMrxUTfW6vWd5WJw7XxLwJ9DFUxT6X7tS8aj+fr/VPIozvNYDtFSLI/4mqIs8 nH9zyZd9ioK0Rck+6/+u7Tsqzu9J2cct+H3U1UFdbKSaZxg2UDfw/Glkl2jSmh6vKysF6LgWpw2 Lq2pOvvMnO0BpiJcccPT5tiNjkvggdSdGlBCeveoRG9rKL3guNZmvX6vLc7sXsZ4wyi98BmohuF D03m3V4Hl6nCl2yRfSAmBhYDASoSrgySjQ9gsH9+KEtgiT2aasUIM4lG9+dEe4URedrlOiR+g5j 43ltPF+D7gKfIlc9Ahlou/LUrwHp3qR8j2fnRx8mYClkC9PppYhB9FJRs+LCiaJGtXAZLcPRHdi ijk/UHb3RV6yP45ktwg== X-Proofpoint-ORIG-GUID: Z9gBGfJv4YrXzi45b0jSQ8_rbtmzd5ws X-Proofpoint-Spam-Info: AW1haW4tMjYwOTAyMDA3MCBTYWx0ZWRfX1eINHSzT2ujO TH6kMMJZ9sI97OOY17eJfPQkbahQxVxIlkGHm4vD+RnzUngsAZ2wsqanN1WuzTeJeLdlLVCMN7W 1cmBj4yRXW+6VJ7qNEODiTYVaqbQMps= X-Authority-Analysis: v=2.4 cv=B92JFutM c=1 sm=1 tr=0 ts=6a97dce7 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=kj9zAlcOel0A:10 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VwQbUJbxAAAA:8 a=LZd3j2bqb7V-iaZHDUcA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-02_01,2026-09-01_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 spamscore=0 clxscore=1015 suspectscore=0 phishscore=0 lowpriorityscore=0 bulkscore=0 priorityscore=1501 impostorscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2609020070 On Tue, Sep 01, 2026 at 05:38:53PM -0700, Sean Christopherson wrote: > On Mon, Aug 31, 2026, Steffen Eiden wrote: > > Only defining KVM_MMIO is not flexible enough for multi-KVM systems > > where one KVM implements MMIO but others do not. Solve this by > > additionally testing for the non-existence of KVM_NO_MMIO before > > including MMIO code to KVM. > > Ewwwww. IIUC, s390 ends up with two KVM modules, i.e. there really are two different > KVMs being built. Rather than have a KVM_MMIO and NO_KVM_MMIO, I vote very > strongly to drop CONFIG_KVM_MMIO entirely and replace it with __KVM_HAVE_ARCH_MMIO, > a la __KVM_HAVE_ARCH_VM_FREE and others. Tracking two separate macros is going > to be annoying to maintain, and will definitely be confusing for non-s390 people. You understand correclty we compile kvm twice into different modules. I already did this approach (with a differnt name) and dropped the config in (v1,v2,v3, and) v4 of this Series[1] and Marc voted against this :) I have no strong opinion on this and do whatever the both of you come up with :) > > It'll mean linking in an emtpy coalesced_mmio.o on s390 when building without arm64 > support, but I'm guessing that won't be at all common for s390 builds. This should be no problem, I assume. Steffen [1] https://lore.kernel.org/all/87a4s37scc.wl-maz@kernel.org/