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 9EE21311955; Mon, 27 Oct 2025 12:29:48 +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=1761568190; cv=none; b=BwIthot1w/eCkrNPRA7fYNFi04XoXQUgFSpCV/7xsyxLm7MLsT2GJgRO7KnuuVHTQnfLvPyxtqYhAmNjj7/DvHV45WbvAlRGDGFoijOI2neUeWnhb6R2i7Gqc/RV0x3HcaTGj8f97G/HD+SXNgQyqfhglXDnni5oMAJRnh9M0Xk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761568190; c=relaxed/simple; bh=7Je6lJRTzVybFGA3zHQ739rKcyvXzeRsZFL0c51Mzjg=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=XaSY9owK+ryF7lsIXm5anBalBpHoBZQF5LYwra/ZZqBvTMZ+eWv4qwwsDonnCJUd+XyO8mJ/3l+yoQs8FDXWNzOG1L8op+uxLSrgQqeeQixZQT3xG6HgVrWxshaNQAjD73OnM6+o0AEolh9ulzt15UWHy1ulWNLvHnVCDhnMTF0= 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=Zdav9Am2; 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="Zdav9Am2" Received: from pps.filterd (m0353729.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 59QME1KF018636; Mon, 27 Oct 2025 12:29:41 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=ItbSC0 3yyhrCbzRRdb4MImfe34nqCTQUGBQZXncdSEI=; b=Zdav9Am2mmUI0AvrdEvO1W WS/2fLSa2CWobO8w/AytWdccmVcB4+cqMOofG7TZMvjX3+ophOkJXRMYXW/Spkvs 6p+ZW72C8TJJLKXOe7WFhoWyy2+4drap+jFfQaisLQoz1+YZS/hzjN/hEUreGyyE oElTL/1lALM1ub7BpgQL+pWLbjvJBLYICISrMBhdajllXluo1+Xvnx+4azi/m/el axQl6g430ZiyhbrvICNgkxI5kL3EVSjTstKhmXwNmGtRETI7N/Hv1sUrMfvb7FQ1 vjHzxckDE4jHdcbWm1AVn8u9kP3Psv8upoSpFksQc8oaGAwNhW5GLA9EzWfk0vzQ == Received: from ppma12.dal12v.mail.ibm.com (dc.9e.1632.ip4.static.sl-reverse.com [50.22.158.220]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4a0p81pptx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 27 Oct 2025 12:29:41 +0000 (GMT) Received: from pps.filterd (ppma12.dal12v.mail.ibm.com [127.0.0.1]) by ppma12.dal12v.mail.ibm.com (8.18.1.2/8.18.1.2) with ESMTP id 59RB0OZ4021604; Mon, 27 Oct 2025 12:29:40 GMT Received: from smtprelay02.wdc07v.mail.ibm.com ([172.16.1.69]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 4a18vrwmjb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 27 Oct 2025 12:29:40 +0000 Received: from smtpav03.dal12v.mail.ibm.com (smtpav03.dal12v.mail.ibm.com [10.241.53.102]) by smtprelay02.wdc07v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 59RCTcvs32244304 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 27 Oct 2025 12:29:38 GMT Received: from smtpav03.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 64AB858061; Mon, 27 Oct 2025 12:29:38 +0000 (GMT) Received: from smtpav03.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1AA425803F; Mon, 27 Oct 2025 12:29:36 +0000 (GMT) Received: from [9.111.45.227] (unknown [9.111.45.227]) by smtpav03.dal12v.mail.ibm.com (Postfix) with ESMTP; Mon, 27 Oct 2025 12:29:35 +0000 (GMT) Message-ID: Subject: Re: [PATCH v2 1/2] PCI: Allow per function PCI slots From: Niklas Schnelle To: Farhan Ali , linux-s390@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Cc: helgaas@kernel.org, mjrosato@linux.ibm.com, bblock@linux.ibm.com, agordeev@linux.ibm.com, gor@linux.ibm.com, hca@linux.ibm.com, stable@vger.kernel.org, Tianrui Zhao , Bibo Mao , Huacai Chen Date: Mon, 27 Oct 2025 13:29:35 +0100 In-Reply-To: <20251022212411.1989-2-alifm@linux.ibm.com> References: <20251022212411.1989-1-alifm@linux.ibm.com> <20251022212411.1989-2-alifm@linux.ibm.com> Autocrypt: addr=schnelle@linux.ibm.com; prefer-encrypt=mutual; keydata=mQINBGHm3M8BEAC+MIQkfoPIAKdjjk84OSQ8erd2OICj98+GdhMQpIjHXn/RJdCZLa58k /ay5x0xIHkWzx1JJOm4Lki7WEzRbYDexQEJP0xUia0U+4Yg7PJL4Dg/W4Ho28dRBROoJjgJSLSHwc 3/1pjpNlSaX/qg3ZM8+/EiSGc7uEPklLYu3gRGxcWV/944HdUyLcnjrZwCn2+gg9ncVJjsimS0ro/ 2wU2RPE4ju6NMBn5Go26sAj1owdYQQv9t0d71CmZS9Bh+2+cLjC7HvyTHKFxVGOznUL+j1a45VrVS XQ+nhTVjvgvXR84z10bOvLiwxJZ/00pwNi7uCdSYnZFLQ4S/JGMs4lhOiCGJhJ/9FR7JVw/1t1G9a UlqVp23AXwzbcoV2fxyE/CsVpHcyOWGDahGLcH7QeitN6cjltf9ymw2spBzpRnfFn80nVxgSYVG1d w75ksBAuQ/3e+oTQk4GAa2ShoNVsvR9GYn7rnsDN5pVILDhdPO3J2PGIXa5ipQnvwb3EHvPXyzakY tK50fBUPKk3XnkRwRYEbbPEB7YT+ccF/HioCryqDPWUivXF8qf6Jw5T1mhwukUV1i+QyJzJxGPh19 /N2/GK7/yS5wrt0Lwxzevc5g+jX8RyjzywOZGHTVu9KIQiG8Pqx33UxZvykjaqTMjo7kaAdGEkrHZ dVHqoPZwhCsgQARAQABtChOaWtsYXMgU2NobmVsbGUgPHNjaG5lbGxlQGxpbnV4LmlibS5jb20+iQ JXBBMBCABBAhsBBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAAhkBFiEEnbAAstJ1IDCl9y3cr+Q/Fej CYJAFAmesutgFCQenEYkACgkQr+Q/FejCYJDIzA//W5h3t+anRaztihE8ID1c6ifS7lNUtXr0wEKx Qm6EpDQKqFNP+n3R4A5w4gFqKv2JpYQ6UJAAlaXIRTeT/9XdqxQlHlA20QWI7yrJmoYaF74ZI9s/C 8aAxEzQZ64NjHrmrZ/N9q8JCTlyhk5ZEV1Py12I2UH7moLFgBFZsPlPWAjK2NO/ns5UJREAJ04pR9 XQFSBm55gsqkPp028cdoFUD+IajGtW7jMIsx/AZfYMZAd30LfmSIpaPAi9EzgxWz5habO1ZM2++9e W6tSJ7KHO0ZkWkwLKicrqpPvA928eNPxYtjkLB2XipdVltw5ydH9SLq0Oftsc4+wDR8TqhmaUi8qD Fa2I/0NGwIF8hjwSZXtgJQqOTdQA5/6voIPheQIi0NBfUr0MwboUIVZp7Nm3w0QF9SSyTISrYJH6X qLp17NwnGQ9KJSlDYCMCBJ+JGVmlcMqzosnLli6JszAcRmZ1+sd/f/k47Fxy1i6o14z9Aexhq/UgI 5InZ4NUYhf5pWflV41KNupkS281NhBEpChoukw25iZk0AsrukpJ74x69MJQQO+/7PpMXFkt0Pexds XQrtsXYxLDQk8mgjlgsvWl0xlk7k7rddN1+O/alcv0yBOdvlruirtnxDhbjBqYNl8PCbfVwJZnyQ4 SAX2S9XiGeNtWfZ5s2qGReyAcd2nBna0KU5pa2xhcyBTY2huZWxsZSA8bmlrbGFzLnNjaG5lbGxlQ GlibS5jb20+iQJUBBMBCAA+AhsBBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAFiEEnbAAstJ1IDCl9y 3cr+Q/FejCYJAFAmesuuEFCQenEYkACgkQr+Q/FejCYJCosA/9GCtbN8lLQkW71n/CHR58BAA5ct1 KRYiZNPnNNAiAzjvSb0ezuRVt9H0bk/tnj6pPj0zdyU2bUj9Ok3lgocWhsF2WieWbG4dox5/L1K28 qRf3p+vdPfu7fKkA1yLE5GXffYG3OJnqR7OZmxTnoutj81u/tXO95JBuCSJn5oc5xMQvUUFzLQSbh prIWxcnzQa8AHJ+7nAbSiIft/+64EyEhFqncksmzI5jiJ5edABiriV7bcNkK2d8KviUPWKQzVlQ3p LjRJcJJHUAFzsZlrsgsXyZLztAM7HpIA44yo+AVVmcOlmgPMUy+A9n+0GTAf9W3y36JYjTS+ZcfHU KP+y1TRGRzPrFgDKWXtsl1N7sR4tRXrEuNhbsCJJMvcFgHsfni/f4pilabXO1c5Pf8fiXndCz04V8 ngKuz0aG4EdLQGwZ2MFnZdyf3QbG3vjvx7XDlrdzH0wUgExhd2fHQ2EegnNS4gNHjq82uLPU0hfcr obuI1D74nV0BPDtr7PKd2ryb3JgjUHKRKwok6IvlF2ZHMMXDxYoEvWlDpM1Y7g81NcKoY0BQ3ClXi a7vCaqAAuyD0zeFVGcWkfvxYKGqpj8qaI/mA8G5iRMTWUUUROy7rKJp/y2ioINrCul4NUJUujfx4k 7wFU11/YNAzRhQG4MwoO5e+VY66XnAd+XPyBIlvy0K05pa2xhcyBTY2huZWxsZSA8bmlrbGFzLnNj aG5lbGxlQGdtYWlsLmNvbT6JAlQEEwEIAD4CGwEFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AWIQSds ACy0nUgMKX3Ldyv5D8V6MJgkAUCZ6y64QUJB6cRiQAKCRCv5D8V6MJgkEr/D/9iaYSYYwlmTJELv+ +EjsIxXtneKYpjXEgNnPwpKEXNIpuU/9dcVDcJ10MfvWBPi3sFbIzO9ETIRyZSgrjQxCGSIhlbom4 D8jVzTA698tl9id0FJKAi6T0AnBF7CxyqofPUzAEMSj9ynEJI/Qu8pHWkVp97FdJcbsho6HNMthBl +Qgj9l7/Gm1UW3ZPvGYgU75uB/mkaYtEv0vYrSZ+7fC2Sr/O5SM2SrNk+uInnkMBahVzCHcoAI+6O Enbag+hHIeFbqVuUJquziiB/J4Z2yT/3Ps/xrWAvDvDgdAEr7Kn697LLMRWBhGbdsxdHZ4ReAhc8M 8DOcSWX7UwjzUYq7pFFil1KPhIkHctpHj2Wvdnt+u1F9fN4e3C6lckUGfTVd7faZ2uDoCCkJAgpWR 10V1Q1Cgl09VVaoi6LcGFPnLZfmPrGYiDhM4gyDDQJvTmkB+eMEH8u8V1X30nCFP2dVvOpevmV5Uk onTsTwIuiAkoTNW4+lRCFfJskuTOQqz1F8xVae8KaLrUt2524anQ9x0fauJkl3XdsVcNt2wYTAQ/V nKUNgSuQozzfXLf+cOEbV+FBso/1qtXNdmAuHe76ptwjEfBhfg8L+9gMUthoCR94V0y2+GEzR5nlD 5kfu8ivV/gZvij+Xq3KijIxnOF6pd0QzliKadaFNgGw4FoUeZo0rQhTmlrbGFzIFNjaG5lbGxlIDx uaWtzQGtlcm5lbC5vcmc+iQJUBBMBCAA+AhsBBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAFiEEnbAA stJ1IDCl9y3cr+Q/FejCYJAFAmesuuEFCQenEYkACgkQr+Q/FejCYJC6yxAAiQQ5NAbWYKpkxxjP/ AajXheMUW8EtK7EMJEKxyemj40laEs0wz9owu8ZDfQl4SPqjjtcRzUW6vE6JvfEiyCLd8gUFXIDMS l2hzuNot3sEMlER9kyVIvemtV9r8Sw1NHvvCjxOMReBmrtg9ooeboFL6rUqbXHW+yb4GK+1z7dy+Q 9DMlkOmwHFDzqvsP7eGJN0xD8MGJmf0L5LkR9LBc+jR78L+2ZpKA6P4jL53rL8zO2mtNQkoUO+4J6 0YTknHtZrqX3SitKEmXE2Is0Efz8JaDRW41M43cE9b+VJnNXYCKFzjiqt/rnqrhLIYuoWCNzSJ49W vt4hxfqh/v2OUcQCIzuzcvHvASmt049ZyGmLvEz/+7vF/Y2080nOuzE2lcxXF1Qr0gAuI+wGoN4gG lSQz9pBrxISX9jQyt3ztXHmH7EHr1B5oPus3l/zkc2Ajf5bQ0SE7XMlo7Pl0Xa1mi6BX6I98CuvPK SA1sQPmo+1dQYCWmdQ+OIovHP9Nx8NP1RB2eELP5MoEW9eBXoiVQTsS6g6OD3rH7xIRxRmuu42Z5e 0EtzF51BjzRPWrKSq/mXIbl5nVW/wD+nJ7U7elW9BoJQVky03G0DhEF6fMJs08DGG3XoKw/CpGtMe 2V1z/FRotP5Fkf5VD3IQGtkxSnO/awtxjlhytigylgrZ4wDpSE= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=fIQ0HJae c=1 sm=1 tr=0 ts=68ff65b5 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=x6icFKpwvdMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=haNJBbb0vfJ8gEqE9DAA:9 a=QEXdDO2ut3YA:10 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-ORIG-GUID: cDAq5HsdiP5JusLCv-gGE1TZ7xurvbyY X-Proofpoint-GUID: cDAq5HsdiP5JusLCv-gGE1TZ7xurvbyY X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMDI1MDAyNCBTYWx0ZWRfX1Vjh2Dt9rhi4 TwNOI5KSkBoBQzJRo16orDU7CN4uWz/FU0Gkonilzqla6hlAE6lEzWIy19OgUOy4rYax6uMtU57 t8st+5iEb3q+MtmzpGc5LBuFnlmEuLxeq0CnSXiR1+Ej50HmAtEtcM99Hx0+Bv17plWe7DoB50X VHayFIYQSd4uKDxVsN/6HBlmvWQPjb67BVFgEy2pY4Sez6y+mLPkiVsw1BDgGW/5qwOVnSq4GV1 e5QOEBnOgEFaqM7TMfHSxtzvx2vHfvbK+3xN8IzPP8a/wltYNM2lfku9gxDeVI80afkgwXvKE6W CA+WLKRWZ8tzSjYC1BNoLeSiQ3dE37AuPpomj/wRwe4fAASahh2Qd9z7EIh+n1z581zgJUDR2pw oCMFpIFrzL2uq/VNDBtEnpSRm6UhzQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-10-27_05,2025-10-22_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 priorityscore=1501 adultscore=0 suspectscore=0 spamscore=0 clxscore=1011 bulkscore=0 lowpriorityscore=0 phishscore=0 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510020000 definitions=main-2510250024 On Wed, 2025-10-22 at 14:24 -0700, Farhan Ali wrote: > On s390 systems, which use a machine level hypervisor, PCI devices are > always accessed through a form of PCI pass-through which fundamentally > operates on a per PCI function granularity. This is also reflected in the > s390 PCI hotplug driver which creates hotplug slots for individual PCI > functions. Its reset_slot() function, which is a wrapper for > zpci_hot_reset_device(), thus also resets individual functions. >=20 > Currently, the kernel's PCI_SLOT() macro assigns the same pci_slot object > to multifunction devices. This approach worked fine on s390 systems that > only exposed virtual functions as individual PCI domains to the operating > system. Since commit 44510d6fa0c0 ("s390/pci: Handling multifunctions") > s390 supports exposing the topology of multifunction PCI devices by > grouping them in a shared PCI domain. When attempting to reset a function > through the hotplug driver, the shared slot assignment causes the wrong > function to be reset instead of the intended one. It also leaks memory as > we do create a pci_slot object for the function, but don't correctly free > it in pci_slot_release(). >=20 > Add a flag for struct pci_slot to allow per function PCI slots for > functions managed through a hypervisor, which exposes individual PCI > functions while retaining the topology. I wonder if LoongArch which now also does per PCI function pass-through might need this too. Adding their KVM maintainers. >=20 > Fixes: 44510d6fa0c0 ("s390/pci: Handling multifunctions") > Cc: stable@vger.kernel.org > Suggested-by: Niklas Schnelle > Signed-off-by: Farhan Ali > --- > drivers/pci/pci.c | 5 +++-- > drivers/pci/slot.c | 25 ++++++++++++++++++++++--- > include/linux/pci.h | 1 + > 3 files changed, 26 insertions(+), 5 deletions(-) >=20 > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index b14dd064006c..36ee38e0d817 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -4980,8 +4980,9 @@ static int pci_reset_hotplug_slot(struct hotplug_sl= ot *hotplug, bool probe) > =20 > static int pci_dev_reset_slot_function(struct pci_dev *dev, bool probe) > { > - if (dev->multifunction || dev->subordinate || !dev->slot || > - dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET) > + if (dev->subordinate || !dev->slot || > + dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET || > + (dev->multifunction && !dev->slot->per_func_slot)) > return -ENOTTY; > =20 > return pci_reset_hotplug_slot(dev->slot->hotplug, probe); > diff --git a/drivers/pci/slot.c b/drivers/pci/slot.c > index 50fb3eb595fe..ed10fa3ae727 100644 > --- a/drivers/pci/slot.c > +++ b/drivers/pci/slot.c > @@ -63,6 +63,22 @@ static ssize_t cur_speed_read_file(struct pci_slot *sl= ot, char *buf) > return bus_speed_read(slot->bus->cur_bus_speed, buf); > } > =20 > +static bool pci_dev_matches_slot(struct pci_dev *dev, struct pci_slot *s= lot) > +{ > + if (slot->per_func_slot) > + return dev->devfn =3D=3D slot->number; > + > + return PCI_SLOT(dev->devfn) =3D=3D slot->number; > +} > + > +static bool pci_slot_enabled_per_func(void) > +{ > + if (IS_ENABLED(CONFIG_S390)) > + return true; > + > + return false; > +} > + --- snip --- > =20 > diff --git a/include/linux/pci.h b/include/linux/pci.h > index d1fdf81fbe1e..6ad194597ab5 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -78,6 +78,7 @@ struct pci_slot { > struct list_head list; /* Node in list of slots */ > struct hotplug_slot *hotplug; /* Hotplug info (move here) */ > unsigned char number; /* PCI_SLOT(pci_dev->devfn) */ > + unsigned int per_func_slot:1; /* Allow per function slot */ > struct kobject kobj; > }; > =20 Reviewed-by: Niklas Schnelle