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Thu, 28 Apr 2022 08:07:19 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6EB4C4C040; Thu, 28 Apr 2022 08:07:19 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2E2054C044; Thu, 28 Apr 2022 08:07:19 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 28 Apr 2022 08:07:19 +0000 (GMT) From: Niklas Schnelle To: Bjorn Helgaas , Jan Kiszka , Matthew Rosato , Pierre Morel Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-s390@vger.kernel.org, linux-pci@vger.kernel.org Subject: [PATCH v5 2/4] PCI: Move jailhouse's isolated function handling to pci_scan_slot() Date: Thu, 28 Apr 2022 10:07:16 +0200 Message-Id: <20220428080718.3094464-3-schnelle@linux.ibm.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220428080718.3094464-1-schnelle@linux.ibm.com> References: <20220428080718.3094464-1-schnelle@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-GUID: h3vu6NpiKc1Lkc7QlOOnoNIOtdGxAevY X-Proofpoint-ORIG-GUID: NWJDT8M5a_TtT6KVhxO0PWnDXrjZIFJg X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-04-27_04,2022-04-27_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 malwarescore=0 mlxscore=0 adultscore=0 mlxlogscore=999 priorityscore=1501 bulkscore=0 clxscore=1015 lowpriorityscore=0 spamscore=0 suspectscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2204280049 X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org The special case of the jailhouse hypervisor passing through individual PCI functions handles scanning for PCI functions even if function 0 does not exist. Currently this is done with an extra loop duplicating the one in pci_scan_slot(). By incorporating the check for jailhouse_paravirt() into pci_scan_slot() we can instead do this as part of the normal slot scan. Note that with the assignment of dev->multifunction gated by fn > 0 we set dev->multifunction unconditionally for all functions if function 0 is missing just as in the existing jailhouse loop. The only functional change is that we now call pcie_aspm_init_link_state() for these functions but this already happened if function 0 was passed through and should not be a problem. Cc: Jan Kiszka Link: https://lore.kernel.org/linux-pci/20220408224514.GA353445@bhelgaas/ Suggested-by: Bjorn Helgaas Signed-off-by: Niklas Schnelle --- drivers/pci/probe.c | 30 ++++++++++-------------------- 1 file changed, 10 insertions(+), 20 deletions(-) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 78aa1bccab2f..3029edc68ff7 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2658,8 +2658,13 @@ int pci_scan_slot(struct pci_bus *bus, int devfn) if (fn > 0) dev->multifunction = 1; } else if (fn == 0) { - /* function 0 is required */ - break; + /* + * function 0 is required unless we are running on + * a hypervisor which passes through individual PCI + * functions. + */ + if (!jailhouse_paravirt()) + break; } fn = next_fn(bus, dev, fn); } while (fn >= 0); @@ -2858,29 +2863,14 @@ static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus, { unsigned int used_buses, normal_bridges = 0, hotplug_bridges = 0; unsigned int start = bus->busn_res.start; - unsigned int devfn, fn, cmax, max = start; + unsigned int devfn, cmax, max = start; struct pci_dev *dev; - int nr_devs; dev_dbg(&bus->dev, "scanning bus\n"); /* Go find them, Rover! */ - for (devfn = 0; devfn < 256; devfn += 8) { - nr_devs = pci_scan_slot(bus, devfn); - - /* - * The Jailhouse hypervisor may pass individual functions of a - * multi-function device to a guest without passing function 0. - * Look for them as well. - */ - if (jailhouse_paravirt() && nr_devs == 0) { - for (fn = 1; fn < 8; fn++) { - dev = pci_scan_single_device(bus, devfn + fn); - if (dev) - dev->multifunction = 1; - } - } - } + for (devfn = 0; devfn < 256; devfn += 8) + pci_scan_slot(bus, devfn); /* Reserve buses for SR-IOV capability */ used_buses = pci_iov_bus_range(bus);