From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 26 Jul 2016 15:24:22 -0500 From: Bjorn Helgaas To: Rui Wang Cc: tglx@linutronix.de, rjw@rjwysocki.net, tony.luck@intel.com, bhelgaas@google.com, linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/4] x86/ioapic: Fix lost ioapic resource after hot-removal and hotadd Message-ID: <20160726202422.GF15037@localhost> References: <1469549597-19253-1-git-send-email-rui.y.wang@intel.com> <1469549597-19253-4-git-send-email-rui.y.wang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1469549597-19253-4-git-send-email-rui.y.wang@intel.com> Sender: linux-acpi-owner@vger.kernel.org List-ID: On Wed, Jul 27, 2016 at 12:13:16AM +0800, Rui Wang wrote: > ioapic resource at 0xfecxxxxx gets lost from /proc/iomem after > hot-removing and then hot-adding the ioapic devices. > > After system boot, in /proc/iomem: > fec00000-fecfffff : PNP0003:00 > fec00000-fec003ff : IOAPIC 0 > fec01000-fec013ff : IOAPIC 1 > fec40000-fec403ff : IOAPIC 2 > fec80000-fec803ff : IOAPIC 3 > fecc0000-fecc03ff : IOAPIC 4 > > Then hot-remove IOAPIC 2 and hot-add it again: > fec00000-fecfffff : PNP0003:00 > fec00000-fec003ff : IOAPIC 0 > fec01000-fec013ff : IOAPIC 1 > fec80000-fec803ff : IOAPIC 3 > fecc0000-fecc03ff : IOAPIC 4 > > The range at 0xfec40000 is lost from /proc/iomem. It is because > handle_ioapic_add() requests resource from either PCI config BAR or > acpi _CRS, not both. But Intel platforms map the IOxAPIC registers s/acpi/ACPI/ s/ioapic/IOAPIC/ throughout > at both the PCI config BAR (called MBAR) and the 0xfecX_YZ00 to > 0xfecX_Y2FF range (called ABAR). Both of the ranges should be claimed I guess you mean the 0xfecX_YZ00-0xfecX_Y2FF range appears in _CRS? > from /proc/iomem for exclusive use. > > Signed-off-by: Rui Wang > --- > drivers/acpi/ioapic.c | 36 ++++++++++++++++++++---------------- > 1 file changed, 20 insertions(+), 16 deletions(-) > > diff --git a/drivers/acpi/ioapic.c b/drivers/acpi/ioapic.c > index daf4a40..80b0b1a 100644 > --- a/drivers/acpi/ioapic.c > +++ b/drivers/acpi/ioapic.c > @@ -97,7 +97,7 @@ static acpi_status handle_ioapic_add(acpi_handle handle, u32 lvl, > unsigned long long gsi_base; > struct acpi_pci_ioapic *ioapic; > struct pci_dev *dev = NULL; > - struct resource *res = NULL; > + struct resource *res = NULL, *pci_res, *crs_res; > char *type = NULL; > > if (!acpi_is_ioapic(handle, &type)) > @@ -137,23 +137,28 @@ static acpi_status handle_ioapic_add(acpi_handle handle, u32 lvl, > pci_set_master(dev); > if (pci_request_region(dev, 0, type)) > goto exit_disable; > - res = &dev->resource[0]; > + pci_res = &dev->resource[0]; > ioapic->pdev = dev; > } else { > pci_dev_put(dev); > dev = NULL; > + } > > - res = &ioapic->res; > - acpi_walk_resources(handle, METHOD_NAME__CRS, setup_res, res); > - if (res->flags == 0) { > - acpi_handle_warn(handle, "failed to get resource\n"); > - goto exit_free; > - } else if (request_resource(&iomem_resource, res)) { > - acpi_handle_warn(handle, "failed to insert resource\n"); > - goto exit_free; > - } > + crs_res = &ioapic->res; > + acpi_walk_resources(handle, METHOD_NAME__CRS, setup_res, crs_res); > + if (crs_res->flags == 0) { > + acpi_handle_warn(handle, "failed to get resource\n"); > + goto exit_release; > + } else if (request_resource(&iomem_resource, crs_res)) { > + acpi_handle_warn(handle, "failed to insert resource\n"); > + goto exit_release; > } > > + /* try pci resource first, then "_CRS" resource */ > + res = pci_res; > + if (!res || !res->flags) > + res = crs_res; > + > if (acpi_register_ioapic(handle, res->start, (u32)gsi_base)) { > acpi_handle_warn(handle, "failed to register IOAPIC\n"); > goto exit_release; > @@ -174,14 +179,13 @@ done: > exit_release: > if (dev) > pci_release_region(dev, 0); > - else > - release_resource(res); > + if (ioapic->res.flags && ioapic->res.parent) > + release_resource(&ioapic->res); > exit_disable: > if (dev) > pci_disable_device(dev); > exit_put: > pci_dev_put(dev); > -exit_free: > kfree(ioapic); > exit: > mutex_unlock(&ioapic_list_lock); > @@ -218,9 +222,9 @@ int acpi_ioapic_remove(struct acpi_pci_root *root) > pci_release_region(ioapic->pdev, 0); > pci_disable_device(ioapic->pdev); > pci_dev_put(ioapic->pdev); > - } else if (ioapic->res.flags && ioapic->res.parent) { > - release_resource(&ioapic->res); > } > + if (ioapic->res.flags && ioapic->res.parent) > + release_resource(&ioapic->res); > list_del(&ioapic->list); > kfree(ioapic); > } > -- > 1.8.3.1 >