From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 39B3C470EB5; Fri, 11 Sep 2026 21:45:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789163110; cv=none; b=r4GSG4Isx02BL0vCRA8xQ/3xCkyRlp2C2hOiLA5lXRbq1/92jRM2ZyKkkabaet+y33P4l6tEfW/A987v8Hc7VlGpCTyra6GTkP5fgRTURf3aiK7z2kgXpfNQWMNwC85zqJ4/3aepaxxqA4/13zt01PiqZCbgROnr3jBVJ38I7AI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789163110; c=relaxed/simple; bh=XR7WX+1I4Qa8NKpz57XIbSye0B7ZlJcCBbh/8m0OVx8=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=BWDqqSdFSVi2iAi+pv7hBY0xlpwgpImjB5wYBnzTmt6V0Tb4wPFaT9QEpH/36AmLSbJ6p77dp3TG1be7vFRCcyVRNZDSM4EZBdq6h9qtTwVXjI7tuncrtF3UJ8isaxlf02Rorr3sEhzJfuiguZ+/6dC+Txrgx70MjDlIl61WeW4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MVsSCJ6O; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="MVsSCJ6O" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6663C1F000FF; Fri, 11 Sep 2026 21:45:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789163108; bh=p53Rp6J0AXK78MBfUyw1lAHpyXwJ7o0RR05tJbr3i3o=; h=Date:From:To:Cc:Subject:In-Reply-To; b=MVsSCJ6OkXjvKudIW7k3VHTHH4ni4zUYvWI5wMiDtnA+kGjDfTR13e+AUE3jCU8f0 fycEDxvTUKUdiB/huYlWV0KmujqOrAoTntb9KtWmkmy/qY0JypyMsbwI8ksphVQDkt RSETsodXnSsJKqfp/jFpRWgELdtcFwp5SkIMFN/PDJm/2JNqVc5uUG2MpBPurIkKLn 7vmaapLJH69yNZ19fDkiJAF1iIx0OjICkCnsEg+ecMUAHP71i8P5sKmIlAo+z/Jg+2 UTRxIYavYVCs2EV1BghMrod2Rgfi6KUgU9luhDLAaaUXt5EwcIwy3ubJ8aclzY88Ht EWciKm/9rXbGg== Date: Fri, 11 Sep 2026 16:45:07 -0500 From: Bjorn Helgaas To: Koichiro Den Cc: Manivannan Sadhasivam , Frank Li , Jon Mason , Dave Jiang , Allen Hubbe , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Kishon Vijay Abraham I , Bjorn Helgaas , ntb@lists.linux.dev, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 2/2] PCI: endpoint: pci-epf-vntb: Manage virtual NTB and PCI bus lifetime Message-ID: <20260911214507.GA582865@bhelgaas> Precedence: bulk X-Mailing-List: ntb@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260901063238.631166-3-den@valinux.co.jp> On Tue, Sep 01, 2026 at 03:32:38PM +0900, Koichiro Den wrote: > The virtual PCI driver registers an ntb_dev but has no remove callback. > Unbinding the endpoint function can therefore free BARs while the NTB > device and its client still use them. It also leaves the virtual PCI > devices and root bus allocated. > > Allocate an ntb_dev for each virtual PCI probe and unregister it from the > matching remove callback. Start command processing only after registration. > Publish the device for doorbell IRQs at the same point. During remove, stop > the command work and drain IRQ handlers before unregistering the device. > > Retain the root bus returned by pci_scan_bus() so it can be removed on > unbind. Unregister the virtual PCI driver before releasing endpoint > resources. Stop and remove the root bus under the PCI rescan/remove lock, > then release its host bridge. > > Fixes: e35f56bb0330 ("PCI: endpoint: Support NTB transfer between RC and EP") > Cc: stable@vger.kernel.org # 6.0+ > Signed-off-by: Koichiro Den > --- > Changes in v6: > - Rework v5 patch 5 on v7.3-rc1. > - Publish ntb_dev only after registration, and tie command work and > doorbell delivery to its lifetime. > - Retain and remove the virtual root bus, then release its host bridge. > - Drop v5 patch 4; f7245901de89 ("PCI: Check parent for NULL in > of_pci_bus_release_domain_nr()") fixed the bug it worked around. > v5: https://lore.kernel.org/r/20260226084142.2226875-6-den@valinux.co.jp/ > > @Frank, the code changed substantially since v5, so I did not carry your > R-b tag. I would appreciate another look. > > drivers/pci/endpoint/functions/pci-epf-vntb.c | 85 +++++++++++++++---- > 1 file changed, 70 insertions(+), 15 deletions(-) > > diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c > index 412e8cc6fb1d..992f5e7f8d4a 100644 > --- a/drivers/pci/endpoint/functions/pci-epf-vntb.c > +++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c > @@ -132,7 +132,7 @@ struct epf_ntb_ctrl { > } __packed; > > struct epf_ntb { > - struct ntb_dev ntb; > + struct ntb_dev *ntb; > struct pci_epf *epf; > struct config_group group; > > @@ -166,10 +166,15 @@ struct epf_ntb { > void __iomem *vpci_mw_addr[MAX_MW]; > > struct delayed_work cmd_handler; > + struct pci_bus *vpci_bus; > }; > > #define to_epf_ntb(epf_group) container_of((epf_group), struct epf_ntb, group) > -#define ntb_ndev(__ntb) container_of(__ntb, struct epf_ntb, ntb) > + > +static struct epf_ntb *ntb_ndev(struct ntb_dev *ntb) > +{ > + return ntb->pdev->sysdata; > +} > > static struct pci_epf_header epf_ntb_header = { > .vendorid = PCI_ANY_ID, > @@ -195,7 +200,7 @@ static int epf_ntb_link_up(struct epf_ntb *ntb, bool link_up) > else > ntb->reg->link_status &= ~LINK_STATUS_UP; > > - ntb_link_event(&ntb->ntb); > + ntb_link_event(ntb->ntb); > return 0; > } > > @@ -284,7 +289,7 @@ static void epf_ntb_cmd_handler(struct work_struct *work) > i++) { > if (ntb->epf_db[i]) { > atomic64_or(1 << (i - EPF_IRQ_DB_START), &ntb->db); > - ntb_db_event(&ntb->ntb, i - EPF_IRQ_DB_START); > + ntb_db_event(ntb->ntb, i - EPF_IRQ_DB_START); > ntb->epf_db[i] = 0; > } > } > @@ -348,12 +353,18 @@ static void epf_ntb_cmd_handler(struct work_struct *work) > static irqreturn_t epf_ntb_doorbell_handler(int irq, void *data) > { > struct epf_ntb *ntb = data; > + struct ntb_dev *ndev; > int i; > > + /* Pair with smp_store_release() in pci_vntb_probe(). */ > + ndev = smp_load_acquire(&ntb->ntb); > + if (!ndev) > + return IRQ_HANDLED; > + > for (i = EPF_IRQ_DB_START; i < ntb->db_count; i++) > if (irq == ntb->epf->db_msg[i].virq) { > atomic64_or(1 << (i - EPF_IRQ_DB_START), &ntb->db); > - ntb_db_event(&ntb->ntb, i - EPF_IRQ_DB_START); > + ntb_db_event(ndev, i - EPF_IRQ_DB_START); > } > > return IRQ_HANDLED; > @@ -985,7 +996,6 @@ static int epf_ntb_epc_init(struct epf_ntb *ntb) > } > > INIT_DELAYED_WORK(&ntb->cmd_handler, epf_ntb_cmd_handler); > - queue_work(kpcintb_workqueue, &ntb->cmd_handler.work); > > atomic64_set(&ntb->peer_db_pending, 0); > enable_work(&ntb->peer_db_work); > @@ -1340,6 +1350,7 @@ static int vpci_scan_bus(void *sysdata) > pci_unlock_rescan_remove(); > return -EINVAL; > } > + ndev->vpci_bus = vpci_bus; > > pci_bus_add_devices(vpci_bus); > > @@ -1425,7 +1436,7 @@ static int vntb_epf_mw_set_trans(struct ntb_dev *ndev, int pidx, int idx, > int ret; > struct device *dev; > > - dev = &ntb->ntb.dev; > + dev = &ndev->dev; > barno = ntb->epf_ntb_bar[BAR_MW1 + idx]; > epf_bar = &ntb->epf->bar[barno]; > epf_bar->phys_addr = addr; > @@ -1563,7 +1574,7 @@ static void vntb_epf_peer_db_work(struct work_struct *work) > ret = pci_epc_raise_irq(epf->epc, func_no, vfunc_no, > PCI_IRQ_MSI, interrupt_num); > if (ret) > - dev_err(&ntb->ntb.dev, > + dev_err(&epf->dev, > "Failed to raise IRQ for interrupt_num %u: %d\n", > interrupt_num, ret); > } > @@ -1681,13 +1692,18 @@ static const struct ntb_dev_ops vntb_epf_ops = { > > static int pci_vntb_probe(struct pci_dev *pdev, const struct pci_device_id *id) > { > - int ret; > struct epf_ntb *ndev = (struct epf_ntb *)pdev->sysdata; > struct device *dev = &pdev->dev; > + struct ntb_dev *ntb; > + int ret; > + > + ntb = devm_kzalloc(dev, sizeof(*ntb), GFP_KERNEL); > + if (!ntb) > + return -ENOMEM; > > - ndev->ntb.pdev = pdev; > - ndev->ntb.topo = NTB_TOPO_NONE; > - ndev->ntb.ops = &vntb_epf_ops; > + ntb->pdev = pdev; > + ntb->topo = NTB_TOPO_NONE; > + ntb->ops = &vntb_epf_ops; > > ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32)); > if (ret) { > @@ -1695,16 +1711,41 @@ static int pci_vntb_probe(struct pci_dev *pdev, const struct pci_device_id *id) > return ret; > } > > - ret = ntb_register_device(&ndev->ntb); > + ret = ntb_register_device(ntb); > if (ret) { > dev_err(dev, "Failed to register NTB device\n"); > return ret; > } > > + /* Publish after ntb_register_device() succeeds. */ > + smp_store_release(&ndev->ntb, ntb); > + queue_delayed_work(kpcintb_workqueue, &ndev->cmd_handler, 0); > + > dev_dbg(dev, "PCI Virtual NTB driver loaded\n"); > return 0; > } > > +static void pci_vntb_remove(struct pci_dev *pdev) > +{ > + struct epf_ntb *ndev = pdev->sysdata; > + struct ntb_dev *ntb; > + unsigned int i; > + > + /* Stop the work reader, then close and drain the IRQ gate. */ > + cancel_delayed_work_sync(&ndev->cmd_handler); > + > + ntb = xchg(&ndev->ntb, NULL); > + > + if (ndev->msi_doorbell) > + for (i = 0; i < ndev->db_count; i++) { > + if (epf_ntb_db_irq_is_duplicated(ndev->epf, i)) > + continue; > + synchronize_irq(ndev->epf->db_msg[i].virq); > + } > + > + ntb_unregister_device(ntb); > +} > + > static struct pci_device_id pci_vntb_table[] = { > { > PCI_DEVICE(0xffff, 0xffff), > @@ -1716,6 +1757,7 @@ static struct pci_driver vntb_pci_driver = { > .name = "pci-vntb", > .id_table = pci_vntb_table, > .probe = pci_vntb_probe, > + .remove = pci_vntb_remove, > }; > > /* ============ PCIe EPF Driver Bind ====================*/ > @@ -1796,12 +1838,25 @@ static int epf_ntb_bind(struct pci_epf *epf) > */ > static void epf_ntb_unbind(struct pci_epf *epf) > { > + struct pci_host_bridge *bridge; > struct epf_ntb *ntb = epf_get_drvdata(epf); > > + pci_unregister_driver(&vntb_pci_driver); > + > + if (ntb->vpci_bus) { > + bridge = to_pci_host_bridge(ntb->vpci_bus->bridge); Where was this host bridge allocated? > + pci_lock_rescan_remove(); > + pci_stop_root_bus(ntb->vpci_bus); > + pci_remove_root_bus(ntb->vpci_bus); > + ntb->vpci_bus = NULL; > + pci_unlock_rescan_remove(); > + > + pci_free_host_bridge(bridge); > + } > + > epf_ntb_epc_cleanup(ntb); > epf_ntb_config_spad_bar_free(ntb); > - > - pci_unregister_driver(&vntb_pci_driver); > } > > // EPF driver probe > -- > 2.51.0 >