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 34B7C30BF4E; Wed, 13 May 2026 16:16:22 +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=1778688984; cv=none; b=NkzR2afQ7nIGgEjXyDcQ29qxLtfliMwuIqDdO6hPFjbx56QLNlvjQ3bbQyukWJz0Ibg2HyAfsxhzBz4wlufkzV6XMm8O2ZBaGtVTWMbb6OOqyKvChajpIXsxmwXzoB43l1mk74Z7K79J7DiuGAhnrfS4OPf/Id7VEGFQXgQu7fg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778688984; c=relaxed/simple; bh=L8jrsYHVTEE8zLHGgLHY9zKU0T0C7rnFaCcc1HD1P6k=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=TLJmt5QgPU832GGzvR4G68FcSh39U6BA0Qp5kpll0CR+5k8jdvSwIsvfH54hO4YokmlxXRjPC6E5YMAAelISeCf9EURcS5kkRpdMIyA/d7CrLgJIOwPKi9dUF/l/Jqx8liNj/k/k8pHK5ORLYfIRDgtk5DNXhS37MCcF7Ei+6+s= 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=GY/1GeDr; 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="GY/1GeDr" Received: from pps.filterd (m0360072.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 64DEhlG52758961; Wed, 13 May 2026 16:16:20 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h= content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=MzMxz1 HePvB4ExTKcFNTUwgHTY03v2TR1E06+VOdB1g=; b=GY/1GeDr2O47EYJX+Omltr dhCOPNlsz/nXWxVL+mqi/1aINIrebpgTunb1MJX9cKapmOL9rgXG0w8gKnjpcCgB 0KiaEn/SG0zBp21YbV92xc735nuyvcQ6ryN1wfnsM6BvtB+maqUcsuWYWvYNzkaq 0QXXa/s4o1ykAS3+MvnZMGfUjVjrI65LQ9dio5L4B3hZUAtNbKwYr5w9VnFTaQ8V JvnN7Bi8UdLmBclXUOsX872f2ZUnBwPwY0SSva8F28OEtFPzqAm6jGYG5V2wrDdv NwsI4iLkiYZr7n1uYo5TPrJ3WDuC78cFAlovKzDg+AjDmkUmhm4Di0pfuRau6FZw == Received: from ppma23.wdc07v.mail.ibm.com (5d.69.3da9.ip4.static.sl-reverse.com [169.61.105.93]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4e3nv6r8b6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 13 May 2026 16:16:19 +0000 (GMT) Received: from pps.filterd (ppma23.wdc07v.mail.ibm.com [127.0.0.1]) by ppma23.wdc07v.mail.ibm.com (8.18.1.7/8.18.1.7) with ESMTP id 64DG9vlf026614; Wed, 13 May 2026 16:16:19 GMT Received: from smtprelay02.dal12v.mail.ibm.com ([172.16.1.4]) by ppma23.wdc07v.mail.ibm.com (PPS) with ESMTPS id 4e3nfgrgjj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 13 May 2026 16:16:19 +0000 (GMT) Received: from smtpav02.wdc07v.mail.ibm.com (smtpav02.wdc07v.mail.ibm.com [10.39.53.229]) by smtprelay02.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 64DGGHSf28574312 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 May 2026 16:16:18 GMT Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AC37D58058; Wed, 13 May 2026 16:16:17 +0000 (GMT) Received: from smtpav02.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E9F4158059; Wed, 13 May 2026 16:16:15 +0000 (GMT) Received: from [9.61.44.159] (unknown [9.61.44.159]) by smtpav02.wdc07v.mail.ibm.com (Postfix) with ESMTP; Wed, 13 May 2026 16:16:15 +0000 (GMT) Message-ID: <9c83dbc9-51db-4ffb-83d2-638128c3b422@linux.ibm.com> Date: Wed, 13 May 2026 12:16:15 -0400 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 2/4] KVM: s390: Enable adapter_indicators_set to use mapped pages To: Douglas Freimuth , borntraeger@linux.ibm.com, imbrenda@linux.ibm.com, frankja@linux.ibm.com, david@kernel.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, svens@linux.ibm.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260511161451.209464-1-freimuth@linux.ibm.com> <20260511161451.209464-3-freimuth@linux.ibm.com> Content-Language: en-US From: Matthew Rosato In-Reply-To: <20260511161451.209464-3-freimuth@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 4gWdGzTY3ZbxHVtj5kxVu2M_YV36Ewc8 X-Proofpoint-GUID: 4gWdGzTY3ZbxHVtj5kxVu2M_YV36Ewc8 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTEzMDE2NCBTYWx0ZWRfX5Ux4h4zeINto I37aDLYNhaDboyCGTnlJScWlMf2fve02HBfuBgcL1UXesWnwjE1uQSm97KJU9ofoErbg58+Iv2K XQpPsdHM17/u8+kaepoYEJa5cjX0uFijZ5a3Dhkn/hGv0wJL271b1aPa11NawZUsKhYtgV40gKo aEg4yEv8THCRdFnYmA4pkeAsUZtmruz7Iv+eKfCeJF5HcOTiJ0oZWg40wtr8mMn419tWAgOzHxX 7Z3mynX0XxECRrMWrDRgEyoZ2aHU7oxECGfZBC7c2YZ1w6is1C/+BbOEqYXVkRipVqWxTpPgkGz ivSovR8GJM3vsw1yo85KkF5Mi1IMisvgE3/K72E322c7VwimRfJynYJmDznice+vcdUuYqqYnVY sqxka/KyZcIMCT/HcD0D4zo7ftAAocirBuoeGnjfj6LvjkIqs+sE6C22QR0gsg9JygMkA6Xa7LQ TuIriOXkQGFwEpmx7eA== X-Authority-Analysis: v=2.4 cv=P8UKQCAu c=1 sm=1 tr=0 ts=6a04a3d3 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=NGcC8JguVDcA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=yJ7A1TyqSRYUUuSQqjIA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-05-13_01,2026-05-13_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 priorityscore=1501 phishscore=0 bulkscore=0 clxscore=1015 malwarescore=0 spamscore=0 lowpriorityscore=0 suspectscore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605050000 definitions=main-2605130164 On 5/11/26 12:14 PM, Douglas Freimuth wrote: > The S390 adapter_indicators_set function needs to be able to use mapped Nit: s/S390/s390/ > pages so that worked can be processed,on a fast path when interrupts are > disabled. If adapter indicator pages are not mapped then local mapping is > done on a slow path as it is prior to this patch. For example, Secure > Execution environments will take the local mapping path as it does prior to > this patch. Slight tweak to the commit message: adapter_indicators_set doesn't really _need_ to use the long-term mapped pages. It's an optimization to do so, while your will later add the _fast() variant where it is a requirement. Maybe re-word like: 'The S390 adapter_indicators_set function can now be optimized to use long-term mapped pages when available so that work can be processed...' [...] > static int adapter_indicators_set(struct kvm *kvm, > struct s390_io_adapter *adapter, > struct kvm_s390_adapter_int *adapter_int) > { > unsigned long bit; > int summary_set, idx; > - struct page *ind_page, *summary_page; > + struct s390_map_info *ind_info, *summary_info; > void *map; > + struct page *ind_page, *summary_page; > + unsigned long flags; > > - ind_page = pin_map_page(kvm, adapter_int->ind_addr, 0); > - if (!ind_page) > - return -1; > - summary_page = pin_map_page(kvm, adapter_int->summary_addr, 0); > - if (!summary_page) { > - unpin_user_page(ind_page); > - return -1; > + raw_spin_lock_irqsave(&adapter->maps_lock, flags); > + ind_info = get_map_info(adapter, adapter_int->ind_addr); > + if (!ind_info) { > + raw_spin_unlock_irqrestore(&adapter->maps_lock, flags); > + ind_page = pin_map_page(kvm, adapter_int->ind_addr, 0); > + if (!ind_page) > + return -1; > + idx = srcu_read_lock(&kvm->srcu); > + map = page_address(ind_page); > + bit = get_ind_bit(adapter_int->ind_addr, > + adapter_int->ind_offset, adapter->swap); > + set_bit(bit, map); > + mark_page_dirty(kvm, adapter_int->ind_gaddr >> PAGE_SHIFT); > + set_page_dirty_lock(ind_page); > + srcu_read_unlock(&kvm->srcu, idx); I think you can simplify some of this unpin logic by just calling unpin_user_page(ind_page) here? You don't use it past this point and you aren't holding a raw spinlock ... > + } else { > + map = page_address(ind_info->page); > + bit = get_ind_bit(ind_info->addr, adapter_int->ind_offset, adapter->swap); > + set_bit(bit, map); > + raw_spin_unlock_irqrestore(&adapter->maps_lock, flags); > + } > + raw_spin_lock_irqsave(&adapter->maps_lock, flags); > + summary_info = get_map_info(adapter, adapter_int->summary_addr); > + if (!summary_info) { > + raw_spin_unlock_irqrestore(&adapter->maps_lock, flags); > + summary_page = pin_map_page(kvm, adapter_int->summary_addr, 0); > + if (!summary_page) { > + if (!ind_info) { > + WARN_ON_ONCE(!ind_page); > + unpin_user_page(ind_page); > + } ... Then you wouldn't need this !ind_info logic, it's safe to return immediately I also don't think that WARN_ON_ONCE does what was intended. Looking back any my v3 comments, the idea was to catch a case where we map indicator pages and set the associated bits but cannot map summary page. That means if you want a WARN here, then something like... if (!summary_page) { WARN_ON_ONCE(ind_page || ind_info); return -1; } Also ind_page needs to be initialized to NULL for that to work. > + return -1; > + } > + idx = srcu_read_lock(&kvm->srcu); > + map = page_address(summary_page); > + bit = get_ind_bit(adapter_int->summary_addr, > + adapter_int->summary_offset, adapter->swap); > + summary_set = test_and_set_bit(bit, map); > + mark_page_dirty(kvm, adapter_int->summary_gaddr >> PAGE_SHIFT); > + set_page_dirty_lock(summary_page); > + srcu_read_unlock(&kvm->srcu, idx); Same here, unpin_user_page(summary_page) ... > + } else { > + map = page_address(summary_info->page); > + bit = get_ind_bit(summary_info->addr, adapter_int->summary_offset, > + adapter->swap); > + summary_set = test_and_set_bit(bit, map); > + raw_spin_unlock_irqrestore(&adapter->maps_lock, flags); > } > > - idx = srcu_read_lock(&kvm->srcu); > - map = page_address(ind_page); > - bit = get_ind_bit(adapter_int->ind_addr, > - adapter_int->ind_offset, adapter->swap); > - set_bit(bit, map); > - mark_page_dirty(kvm, adapter_int->ind_gaddr >> PAGE_SHIFT); > - set_page_dirty_lock(ind_page); > - map = page_address(summary_page); > - bit = get_ind_bit(adapter_int->summary_addr, > - adapter_int->summary_offset, adapter->swap); > - summary_set = test_and_set_bit(bit, map); > - mark_page_dirty(kvm, adapter_int->summary_gaddr >> PAGE_SHIFT); > - set_page_dirty_lock(summary_page); > - srcu_read_unlock(&kvm->srcu, idx); > - > - unpin_user_page(ind_page); > - unpin_user_page(summary_page); > + if (!ind_info) > + unpin_user_page(ind_page); > + if (!summary_info) > + unpin_user_page(summary_page); ... And then you don't need either of these checks/unpins? > return summary_set ? 0 : 1; > } >