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 CEB1B2E6CD4; Mon, 27 Oct 2025 08:29:07 +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=1761553749; cv=none; b=cyyqwbE19rOpE5fW+RnTL1/3ai5nysqiJBe8XutiwO8BYkWkPQwyl8HEHKeRXJ+bGrzLJf3LywAKFwvbjlg4B+7TDVvcE0XhZV3sp0WuzNGHCrlA2vr9Q4f1o1TsSrmkA6NCfuei4CvDHR7mNCo3cnq4RDaszBfUR1jpQEv11SQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761553749; c=relaxed/simple; bh=1hQUazNcpeZTrpD6AB4wL1Y+5y2Z6029RCNtFDvnnkQ=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=IZGp7ZHagbWbcAgEpeEyBoFuXMukAMzmbPOE7azKAFmuBJ/Kfuu+z2OVLtIJxSIeH79Bh1qd83IG700DP0I6R/rmW8GZi6Wb8kzVrHE+vAkBx9QXLzqlbbzQ7kHB2kqQmegGeAyxAAv3LTdfuXC/29Rvs0mRJ4eMSkrZjyT49C4= 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=ES/UzCCw; 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="ES/UzCCw" 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 59QMtQiO013199; Mon, 27 Oct 2025 08:28:55 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=pKZXXN Ya8yxe9p/HY93/8btDa6q0PDS2UDuGBCqgOHQ=; b=ES/UzCCwF0G9JHkxWM4Gca Wom7om48HOOnJSWRIc1CifX45I/C8R08beiveFQKlwydPzbGHHTzFKXKu4lnRvod r2fC2KNhLWxahXvYYQ+7cNESG5ATjNIqUWFd4ZGqCOyA7B+0v36dCuUiaO7oTe/z RXLU1KnbZdoeCNTDVizfNh7uh4qDVS2fYs4t+lrnDf6q++CF2KWu27sAQviFtTJy XFkT7KgBMIyCv0uEyBnuA4u3fP7/q+l5h4NifWsG4nfxBijpg8uw3Yh594icbkuX ejX1WIyGknFIg4FKpQede6t2RyahXHLt4iNzcWj+rCUt14fqNVJIyZC0UIFQfSjg == Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4a0p98wrvf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 27 Oct 2025 08:28:55 +0000 (GMT) Received: from m0356517.ppops.net (m0356517.ppops.net [127.0.0.1]) by pps.reinject (8.18.1.12/8.18.0.8) with ESMTP id 59R8JQNb016069; Mon, 27 Oct 2025 08:28:55 GMT 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 4a0p98wrvb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 27 Oct 2025 08:28:55 +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 59R3tRqf009404; Mon, 27 Oct 2025 08:28:54 GMT Received: from smtprelay05.dal12v.mail.ibm.com ([172.16.1.7]) by ppma13.dal12v.mail.ibm.com (PPS) with ESMTPS id 4a1b3hvcbr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 27 Oct 2025 08:28:54 +0000 Received: from smtpav05.wdc07v.mail.ibm.com (smtpav05.wdc07v.mail.ibm.com [10.39.53.232]) by smtprelay05.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 59R8Sq0p22807132 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 27 Oct 2025 08:28:53 GMT Received: from smtpav05.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 975D758043; Mon, 27 Oct 2025 08:28:52 +0000 (GMT) Received: from smtpav05.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ED8C558053; Mon, 27 Oct 2025 08:28:48 +0000 (GMT) Received: from [9.111.45.227] (unknown [9.111.45.227]) by smtpav05.wdc07v.mail.ibm.com (Postfix) with ESMTP; Mon, 27 Oct 2025 08:28:48 +0000 (GMT) Message-ID: <6deed02fcbf2c359382f9e96a4f6883d34f5df28.camel@linux.ibm.com> Subject: Re: [PATCH v4 1/2] PCI: Fix isolated PCI function probing with ARI and SR-IOV From: Niklas Schnelle To: Bjorn Helgaas Cc: Jan Kiszka , Huacai Chen , linux-s390 , loongarch@lists.linux.dev, Farhan Ali , Matthew Rosato , Tianrui Zhao , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Sven Schnelle , Christian Borntraeger , Gerd Bayer , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, jailhouse-dev@googlegroups.com Date: Mon, 27 Oct 2025 09:28:48 +0100 In-Reply-To: <20251023-ari_no_bus_dev-v4-1-8482e2ed10bd@linux.ibm.com> References: <20251023-ari_no_bus_dev-v4-0-8482e2ed10bd@linux.ibm.com> <20251023-ari_no_bus_dev-v4-1-8482e2ed10bd@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=JqL8bc4C c=1 sm=1 tr=0 ts=68ff2d47 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=IkcTkHD0fZMA:10 a=x6icFKpwvdMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=-XlZ1Vyswo3uM5Ee-MYA:9 a=QEXdDO2ut3YA:10 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-GUID: v-qIo_EKR-7DRtwJq6tIJkQ1CQse3Tje X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMDI1MDAxOSBTYWx0ZWRfX8jnFSXHUvUUU VI5XAWCjnJZnf4loag1XrLyBf0GAnW9vXkbLYV3vPMXK+O/m1/8pQUNdYfjF5dt7O7WENVKkL79 gXOPYJvAfvT2CzY1H/DHl7kwDUmjpS/PHepTK9X1JZP+sP+aPvCBsr/TBaWCZWaeTYElCaUvIBc okVSSENRSFVGHcrIpXy/ankSoRDjATqE9/VPQM9Y6jI/ks0T+MO55qo5aTkK3MPPCwdbhdwy6ZI fndewSlduwsuIE0UVPRBTST+kRKBnFNWUP1cd1ajNhH7giSGa6zxrcXqJMd8rs/l+xkdgqBlGSt 9DcyylISL0vPjeyy3/RDEqoZaF4yJEQb5RxnClFW5cyZERMBJtZMAuYBgSoTmk/LkFEblQRKUxW hV+6kV+UvbR0KUHR3tJJ1cVwP5f/SQ== X-Proofpoint-ORIG-GUID: KrEU8UmrU9pmpMprLms_b75I_9BvyL_N 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_03,2025-10-22_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 clxscore=1015 lowpriorityscore=0 malwarescore=0 bulkscore=0 priorityscore=1501 spamscore=0 adultscore=0 phishscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510020000 definitions=main-2510250019 On Thu, 2025-10-23 at 17:20 +0200, Niklas Schnelle wrote: > When the isolated PCI function probing mechanism is used in conjunction > with ARI or SR-IOV it may not find all available PCI functions. In the > case of ARI the problem is that next_ari_fn() always returns -ENODEV if > dev is NULL and thus if fn 0 is missing the scan stops. >=20 > For SR-IOV things are more complex. Here the problem is that the check > for multifunction may fail. One example where this can occur is if the > first passed-through function is a VF with devfn 8. Now in > pci_scan_slot() this means it is fn 0 and thus multifunction doesn't get > set. Since VFs don't get multifunction set via PCI_HEADER_TYPE_MFD it > remains unset and probing stops even if there is a devfn 9. >=20 > Now at the moment both of these issues are hidden on s390. The first one > because ARI is detected as disabled as struct pci_bus's self is NULL > even though firmware does enable and use ARI. The second issue is hidden > as a side effect of commit 25f39d3dcb48 ("s390/pci: Ignore RID for > isolated VFs"). This is because VFs are either put on their own virtual > bus if the parent PF is not passed-through to the same instance or VFs > are hotplugged once SR-IOV is enabled on the parent PF and then > pci_scan_single_device() is used. >=20 > Still especially the first issue prevents correct detection of ARI and > the second might be a problem for other users of isolated function > probing. Fix both issues by keeping things as simple as possible. If > isolated function probing is enabled simply scan every possible devfn. >=20 > Fixes: 189c6c33ff42 ("PCI: Extend isolated function probing to s390") Since I'm adding a fixes tag, I should also add Cc stable. Added for next revision. > Link: https://lore.kernel.org/linux-pci/d3f11e8562f589ddb2c1c83e74161bd89= 48084c3.camel@linux.ibm.com/ > Signed-off-by: Niklas Schnelle > --- > drivers/pci/probe.c | 20 ++++++++++++-------- > 1 file changed, 12 insertions(+), 8 deletions(-) >=20 --- snip ---