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Mon, 19 Jan 2026 14:49:12 +0000 (GMT) Message-ID: Date: Mon, 19 Jan 2026 15:49:12 +0100 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] KVM: s390: vsie: retry SIE when unable to get vsie_page To: Eric Farman , Claudio Imbrenda Cc: Christian Borntraeger , David Hildenbrand , Christoph Schlameuss , kvm@vger.kernel.org, linux-s390@vger.kernel.org References: <20251217030107.1729776-1-farman@linux.ibm.com> <8334988f-2caa-4361-b0b9-50b9f41f6d8a@linux.ibm.com> <20260114105033.23d3c699@p-imbrenda> <23154a0c6b4b9e625daa2b1bbaadc349bf3a99ed.camel@linux.ibm.com> <3d997b2645c80396c0f7c69f95fd8ec0d4784b20.camel@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: <3d997b2645c80396c0f7c69f95fd8ec0d4784b20.camel@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: yqRIESMXp1-Cak4pa1Dw4iSeCA9Oamdy X-Proofpoint-ORIG-GUID: yqRIESMXp1-Cak4pa1Dw4iSeCA9Oamdy X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTE5MDEyNCBTYWx0ZWRfX1iDSQgpy61GW ISw7DthlhdcSy70Rd8M5ZTO4dA0ZZfSW+yUh+hwE3eFEcgOajhZJmxmTsVv1w5CrtZrPtmuYM8Z d6DKr/A6TXnCYj5QjFgaJyRbLv63Igjkx8fKzFIa8a3tyV6/xG+Ipp/eMNv7Ho5qvCFxOr4t1kB qboRUBmTV3utp/6LzQV3AhWW/ffVi7mkHMNp1fEVSDJa6LvKvO8nqO7Shc6pdzwCTnJpk/Yaued kFfZkPU4wnWeEzdHW2pHvBKdUA/0LvYKRTd2072nHcOd8pA7x+s8A23uxE90iOp4MO9xpSFDjcw RJ7/qqmXU3DChNA1eb0RTVdPw6Fhz6ZBxfhXw+JyMU9cUxibUL3qEJXz2UsO2lhwB7/EFlHHUUA IanhKUqNqBbhQHqVuLlyd0ihDczS77zL0EqWOBCTSs8CnVrq0N7vWfqVha84YLt0w3e8E1FC3qT cepE69cZUg2IKsQShrA== X-Authority-Analysis: v=2.4 cv=bopBxUai c=1 sm=1 tr=0 ts=696e446e cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=vUbySO9Y5rIA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=3F0M1WNf6RbkfYYVzbkA:9 a=NqO74GWdXPXpGKcKHaDJD/ajO6k=:19 a=QEXdDO2ut3YA:10 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=2026-01-19_03,2026-01-19_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 bulkscore=0 adultscore=0 suspectscore=0 impostorscore=0 phishscore=0 malwarescore=0 lowpriorityscore=0 priorityscore=1501 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2601150000 definitions=main-2601190124 On 1/16/26 16:45, Eric Farman wrote: > On Thu, 2026-01-15 at 16:17 -0500, Eric Farman wrote: >> On Wed, 2026-01-14 at 10:50 +0100, Claudio Imbrenda wrote: >>> On Mon, 05 Jan 2026 10:46:53 -0500 >>> Eric Farman wrote: >>> >>>> On Mon, 2026-01-05 at 13:41 +0100, Janosch Frank wrote: >>>>> On 12/17/25 04:01, Eric Farman wrote: >>>>>> SIE may exit because of pending host work, such as handling an interrupt, >>>>>> in which case VSIE rewinds the guest PSW such that it is transparently >>>>>> resumed (see Fixes tag). There is still one scenario where those conditions >>> >>> can you add a few words to (very briefly) explain what the scenario is? >> >> Maybe if this paragraph were rewritten this way, instead? >> >> --8<-- >> SIE may exit because of pending host work, such as handling an interrupt, >> in which case VSIE rewinds the guest PSW such that it is transparently >> resumed (see Fixes tag). Unlike those other places that return rc=0, this >> return leaves the guest PSW in place, requiring the guest to handle an >> intercept that was meant to be serviced by the host. This showed up when >> testing heavy I/O workloads, when multiple vcpus attempted to dispatch the >> same SIE block and incurred failures inserting them into the radix tree. >> -->8-- > > Spoke to Claudio offline, and he suggested the following edit to the above: > > --8<-- > SIE may exit because of pending host work, such as handling an interrupt, > in which case VSIE rewinds the guest PSW such that it is transparently > resumed (see Fixes tag). Unlike those other places that return rc=0, this > return leaves the guest PSW in place, requiring the guest to handle a > spurious intercept. This showed up when testing heavy I/O workloads, > when multiple vcpus attempted to dispatch the same SIE block and incurred > failures inserting them into the radix tree. > -->8-- > >> >> @Janosch, if that ends up being okay, can you update the patch or do you want me to send a v2? I can fix that up.