From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (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 C147E330328; Tue, 11 Nov 2025 15:47:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.156.1 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762876042; cv=none; b=UAxZH3UX5ZOjtjkfBUrJFqbqxDgzjMbRFuyFzPnUjMU1/fpJ5l1hQPM+O4r4Vtfnc7iFRdEbQyy8z3DWPOfSLm7NPk0Oaf84CZoKiBI83DH8Zw0LVy+fvE/8Nwly1JIRpCcYN0N5wcBLp85QK2QwZQNJw0CO8a++dFqV+iJ2E+o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762876042; c=relaxed/simple; bh=lSRr/eMRfhJG9qFc8yreZvR26GB6xWROBgaCDiGUfp0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=bRBv+ADTU3OTvxszUSBm36wh2pTJVgUDvilzPnTGVRBOF1t7Bku9t9yfTWeAxdg8Q0rU5XCBhmRqxl5MYP1cpUdmDXfeVcvIwMsYTmybmmhthEgQ3Y3LNqZ5Xt4O6I31vJNDIihZJ/PNI56e8Fo4oT4Aoqre6N1Ogovp+Zr/bGY= 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=Xo4o0LhA; arc=none smtp.client-ip=148.163.156.1 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="Xo4o0LhA" Received: from pps.filterd (m0356517.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 5ABF2mMp009449; Tue, 11 Nov 2025 15:47:16 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pp1; bh=ZqahaM W8RlcE7yyQUS+makVDBs7cN1TxIpAimx17qN8=; b=Xo4o0LhANynkAIOoVnHm0x Y1qy/Hv1A845TVxZ1YWx6ZT/KSRYelXpDLYx28P5vuYWshCOw2ElfPwL186uk1pE TipiXFtvi+p/e6QkZGwS/6SUlTxFTk+tYmFYIOZvoht3LO5VG9+z/p7wEMGBoeHN dGpVxQrSBpu+Y0PHgNASvdEp4qXGtD1/GzYLI/C7YorXBg7uSdSOafY59SqaQjlu 2FAjUMSiLC/PASMK++VokhhqkiPUyiqhpset+FxGsTcojDDsOWnqfpyxZsSUvfkR l+29sQSdR4STWc2zQOUhB4jh7DKd0shUF/COLTGcO42vxvVmd1D9YKnubyMHg6yw == 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 4a9wk85xue-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 11 Nov 2025 15:47:16 +0000 (GMT) Received: from pps.filterd (ppma13.dal12v.mail.ibm.com [127.0.0.1]) by ppma13.dal12v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 5ABDaMrA007309; Tue, 11 Nov 2025 15:47:15 GMT Received: from smtprelay04.fra02v.mail.ibm.com ([9.218.2.228]) by ppma13.dal12v.mail.ibm.com (PPS) with ESMTPS id 4aajdjbb43-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 11 Nov 2025 15:47:15 +0000 Received: from smtpav01.fra02v.mail.ibm.com (smtpav01.fra02v.mail.ibm.com [10.20.54.100]) by smtprelay04.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 5ABFlCDp22414004 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 11 Nov 2025 15:47:12 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ED1BA2004D; Tue, 11 Nov 2025 15:47:11 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 50BCC20043; Tue, 11 Nov 2025 15:47:11 +0000 (GMT) Received: from [9.111.10.174] (unknown [9.111.10.174]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 11 Nov 2025 15:47:11 +0000 (GMT) Message-ID: <1a694540-3e7b-4453-8f7f-294eaf904afe@linux.ibm.com> Date: Tue, 11 Nov 2025 16:47:11 +0100 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v2 08/11] KVM: s390: Allow guest-3 cpu add and remove with vsie sigpif To: Christoph Schlameuss , kvm@vger.kernel.org Cc: linux-s390@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Claudio Imbrenda , Nico Boehr , David Hildenbrand , Sven Schnelle , Paolo Bonzini , Shuah Khan References: <20251110-vsieie-v2-0-9e53a3618c8c@linux.ibm.com> <20251110-vsieie-v2-8-9e53a3618c8c@linux.ibm.com> Content-Language: en-US From: Janosch Frank Autocrypt: addr=frankja@linux.ibm.com; keydata= xsFNBFubpD4BEADX0uhkRhkj2AVn7kI4IuPY3A8xKat0ihuPDXbynUC77mNox7yvK3X5QBO6 qLqYr+qrG3buymJJRD9xkp4mqgasHdB5WR9MhXWKH08EvtvAMkEJLnqxgbqf8td3pCQ2cEpv 15mH49iKSmlTcJ+PvJpGZcq/jE42u9/0YFHhozm8GfQdb9SOI/wBSsOqcXcLTUeAvbdqSBZe zuMRBivJQQI1esD9HuADmxdE7c4AeMlap9MvxvUtWk4ZJ/1Z3swMVCGzZb2Xg/9jZpLsyQzb lDbbTlEeyBACeED7DYLZI3d0SFKeJZ1SUyMmSOcr9zeSh4S4h4w8xgDDGmeDVygBQZa1HaoL Esb8Y4avOYIgYDhgkCh0nol7XQ5i/yKLtnNThubAcxNyryw1xSstnKlxPRoxtqTsxMAiSekk 0m3WJwvwd1s878HrQNK0orWd8BzzlSswzjNfQYLF466JOjHPWFOok9pzRs+ucrs6MUwDJj0S cITWU9Rxb04XyigY4XmZ8dywaxwi2ZVTEg+MD+sPmRrTw+5F+sU83cUstuymF3w1GmyofgsU Z+/ldjToHnq21MNa1wx0lCEipCCyE/8K9B9bg9pUwy5lfx7yORP3JuAUfCYb8DVSHWBPHKNj HTOLb2g2UT65AjZEQE95U2AY9iYm5usMqaWD39pAHfhC09/7NQARAQABzSVKYW5vc2NoIEZy YW5rIDxmcmFua2phQGxpbnV4LmlibS5jb20+wsF3BBMBCAAhBQJbm6Q+AhsjBQsJCAcCBhUI CQoLAgQWAgMBAh4BAheAAAoJEONU5rjiOLn4p9gQALjkdj5euJVI2nNT3/IAxAhQSmRhPEt0 AmnCYnuTcHRWPujNr5kqgtyER9+EMQ0ZkX44JU2q7OWxTdSNSAN/5Z7qmOR9JySvDOf4d3mS bMB5zxL9d8SbnSs1uW96H9ZBTlTQnmLfsiM9TetAjSrR8nUmjGhe2YUhJLR1v1LguME+YseT eXnLzIzqqpu311/eYiiIGcmaOjPCE+vFjcXL5oLnGUE73qSYiujwhfPCCUK0850o1fUAYq5p CNBCoKT4OddZR+0itKc/cT6NwEDwdokeg0+rAhxb4Rv5oFO70lziBplEjOxu3dqgIKbHbjza EXTb+mr7VI9O4tTdqrwJo2q9zLqqOfDBi7NDvZFLzaCewhbdEpDYVu6/WxprAY94hY3F4trT rQMHJKQENtF6ZTQc9fcT5I3gAmP+OEvDE5hcTALpWm6Z6SzxO7gEYCnF+qGXqp8sJVrweMub UscyLqHoqdZC2UG4LQ1OJ97nzDpIRe0g6oJ9ZIYHKmfw5jjwH6rASTld5MFWajWdNsqK15k/ RZnHAGICKVIBOBsq26m4EsBlfCdt3b/6emuBjUXR1pyjHMz2awWzCq6/6OWs5eANZ0sdosNq dq2v0ULYTazJz2rlCXV89qRa7ukkNwdBSZNEwsD4eEMicj1LSrqWDZMAALw50L4jxaMD7lPL jJbazsFNBFubpD4BEADAcUTRqXF/aY53OSH7IwIK9lFKxIm0IoFkOEh7LMfp7FGzaP7ANrZd cIzhZi38xyOkcaFY+npGEWvko7rlIAn0JpBO4x3hfhmhBD/WSY8LQIFQNNjEm3vzrMo7b9Jb JAqQxfbURY3Dql3GUzeWTG9uaJ00u+EEPlY8zcVShDltIl5PLih20e8xgTnNzx5c110lQSu0 iZv2lAE6DM+2bJQTsMSYiwKlwTuv9LI9Chnoo6+tsN55NqyMxYqJgElk3VzlTXSr3+rtSCwf tq2cinETbzxc1XuhIX6pu/aCGnNfuEkM34b7G1D6CPzDMqokNFbyoO6DQ1+fW6c5gctXg/lZ 602iEl4C4rgcr3+EpfoPUWzKeM8JXv5Kpq4YDxhvbitr8Dm8gr38+UKFZKlWLlwhQ56r/zAU v6LIsm11GmFs2/cmgD1bqBTNHHcTWwWtRTLgmnqJbVisMJuYJt4KNPqphTWsPY8SEtbufIlY HXOJ2lqUzOReTrie2u0qcSvGAbSfec9apTFl2Xko/ddqPcZMpKhBiXmY8tJzSPk3+G4tqur4 6TYAm5ouitJsgAR61Cu7s+PNuq/pTLDhK+6/Njmc94NGBcRA4qTuysEGE79vYWP2oIAU4Fv6 gqaWHZ4MEI2XTqH8wiwzPdCQPYsSE0fXWiYu7ObeErT6iLSTZGx4rQARAQABwsFfBBgBCAAJ BQJbm6Q+AhsMAAoJEONU5rjiOLn4DDEP/RuyckW65SZcPG4cMfNgWxZF8rVjeVl/9PBfy01K 8R0hajU40bWtXSMiby7j0/dMjz99jN6L+AJHJvrLz4qYRzn2Ys843W+RfXj62Zde4YNBE5SL jJweRCbMWKaJLj6499fctxTyeb9+AMLQS4yRSwHuAZLmAb5AyCW1gBcTWZb8ON5BmWnRqeGm IgC1EvCnHy++aBnHTn0m+zV89BhTLTUal35tcjUFwluBY39R2ux/HNlBO1GY3Z+WYXhBvq7q katThLjaQSmnOrMhzqYmdShP1leFTVbzXUUIYv/GbynO/YrL2gaQpaP1bEUEi8lUAfXJbEWG dnHFkciryi092E8/9j89DJg4mmZqOau7TtUxjRMlBcIliXkzSLUk+QvD4LK1kWievJse4mte FBdkWHfP4BH/+8DxapRcG1UAheSnSRQ5LiO50annOB7oXF+vgKIaie2TBfZxQNGAs3RQ+bga DchCqFm5adiSP5+OT4NjkKUeGpBe/aRyQSle/RropTgCi85pje/juYEn2P9UAgkfBJrOHvQ9 Z+2Sva8FRd61NJLkCJ4LFumRn9wQlX2icFbi8UDV3do0hXJRRYTWCxrHscMhkrFWLhYiPF4i phX7UNdOWBQ90qpHyAxHmDazdo27gEjfvsgYMdveKknEOTEb5phwxWgg7BcIDoJf9UMC In-Reply-To: <20251110-vsieie-v2-8-9e53a3618c8c@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTA4MDAyMiBTYWx0ZWRfX/WFAUW6A6yzI WyuAsv/8fkvnLS9GA1xVVPLC3RGkYefjmBa4GC/JTTIgyhIblunjirsb9hhYHlqY1wBc4iOIIOz iFxALwgsO9SlYRHAVR8X7VbFKBUEbXjEDpyP5dJkt+29V34QZ3/+EtfCx9t1kVN1xbZrdxc3ZBb RLgx5k+N4QxrEv/rBJl4pjZEsDqYzp+VM2lPh6DmRTUfP3sPXOMQrH/qvZ4hIYT+CfcNQCAbDZs Q85UUIckHLmW7QNOAdsqKZk8PyPO+H/yxpp46/+gA2VfWHFHMLBkSTtOXeSUQBIhW16l6aiqdBS AP+aqIubcJQDopBDh7fHlpdfvm/DTInf7TuSgDryQLDgUJnljjrS8VlaAwG5tTBPwlE3N+lCuL4 5quRf/IPA9FzUOAG3gpkDc0S3LPZyA== X-Authority-Analysis: v=2.4 cv=ZK3aWH7b c=1 sm=1 tr=0 ts=69135a84 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=IkcTkHD0fZMA:10 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=KbLqQ6qR0etDXQnJZboA:9 a=QEXdDO2ut3YA:10 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-ORIG-GUID: oFp1qKCN6PF35FHbiMzDF5iL10UHQdDy X-Proofpoint-GUID: oFp1qKCN6PF35FHbiMzDF5iL10UHQdDy X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-11_02,2025-11-11_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 lowpriorityscore=0 priorityscore=1501 suspectscore=0 phishscore=0 impostorscore=0 spamscore=0 bulkscore=0 adultscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511080022 On 11/10/25 18:16, Christoph Schlameuss wrote: > As we are shadowing the SCA we need to add and remove the pointers to > the shadowed control blocks and sca entries whenever the mcn changes. > > It is not expected that the mcn changes frequently for a already running > guest-3 configuration. So we can simply re-init the ssca whenever the > mcn changes. > To detect the mcn change we store the expected mcn in the struct > vsie_sca when running the ssca init. > > Signed-off-by: Christoph Schlameuss > --- > arch/s390/kvm/vsie.c | 20 ++++++++++++++++++-- > 1 file changed, 18 insertions(+), 2 deletions(-) > > diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c > index 72c794945be916cc107aba74e1609d3b4780d4b9..1e15220e1f1ecfd83b10aa0620ca84ff0ff3c1ac 100644 > --- a/arch/s390/kvm/vsie.c > +++ b/arch/s390/kvm/vsie.c > @@ -1926,12 +1926,27 @@ static int init_ssca(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, struct > return PTR_ERR(vsie_page_n); > } > > +static bool sca_mcn_equals(struct vsie_sca *sca, u64 *mcn) > +{ > + bool is_esca = test_bit(VSIE_SCA_ESCA, &sca->flags); > + int i; > + > + if (!is_esca) > + return ((struct bsca_block *)phys_to_virt(sca->ssca->osca))->mcn == *mcn; > + > + for (i = 0; i < 4; i++) > + if (((struct esca_block *)phys_to_virt(sca->ssca->osca))->mcn[i] != sca->mcn[i]) > + return false; You're reimplementing memcmp(), no? Instead of casting which makes the comparison really messy you could use offsetof. Something like this (+- errors): void *osca = phys_to_virt(sca->ssca->osca); int offset = offsetof(struct bsca_block, mcn); int size = 8; if (test_bit(VSIE_SCA_ESCA, &sca->flags)) { size = 8 * 4; offset = offsetof(struct esca_block, mcn); } return !memcmp(osca + offset, mcn, size); > + return true; > +} > + > /* > * Shadow the sca on vsie enter. > */ > static int shadow_sca(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, struct vsie_sca *sca) > { > struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s; > + bool do_init_ssca; > int rc; > > vsie_page->sca = sca; > @@ -1947,8 +1962,9 @@ static int shadow_sca(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, struct > if (!use_vsie_sigpif_for(vcpu->kvm, vsie_page)) > return false; > > - /* skip if the guest does not have an usable sca */ > - if (!sca->ssca->osca) { > + do_init_ssca = !sca->ssca->osca; > + do_init_ssca = do_init_ssca || !sca_mcn_equals(sca, sca->mcn); > + if (do_init_ssca) { > rc = init_ssca(vcpu, vsie_page, sca); > if (rc) > return rc; >