| Message ID | 164740406489.3912056.8334546166826246693.stgit@dwillia2-desk3.amr.corp.intel.com |
|---|---|
| State | New, archived |
| Headers | show |
| Series | cxl/pci: Add fundamental error handling | expand |
On Tue, 15 Mar 2022 21:14:24 -0700 Dan Williams <dan.j.williams@intel.com> wrote: > Add nominal error handling that tears down CXL.mem in response to error > notifications that imply a device reset. Given some CXL.mem may be > operating as System RAM, there is a high likelihood that these error > events are fatal. However, if the system survives the notification the > expectation is that the driver behavior is equivalent to a hot-unplug > and re-plug of an endpoint. > > Note that this does not change the mask values from the default. That > awaits CXL _OSC support to determine whether platform firmware is in > control of the mask registers. > > Signed-off-by: Dan Williams <dan.j.williams@intel.com> I'm far from an expert in PCI error handling... I've asked one of our RAS folk to take a quick look so he may well reply as well. With that in mind... > --- > drivers/cxl/core/memdev.c | 1 > drivers/cxl/cxlmem.h | 2 + > drivers/cxl/pci.c | 109 +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 112 insertions(+) > > diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c > index 1f76b28f9826..223d512790e1 100644 > --- a/drivers/cxl/core/memdev.c > +++ b/drivers/cxl/core/memdev.c > @@ -341,6 +341,7 @@ struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds) > * needed as this is ordered with cdev_add() publishing the device. > */ > cxlmd->cxlds = cxlds; > + cxlds->cxlmd = cxlmd; > > cdev = &cxlmd->cdev; > rc = cdev_device_add(cdev, dev); > diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h > index 5d33ce24fe09..f58e16951414 100644 > --- a/drivers/cxl/cxlmem.h > +++ b/drivers/cxl/cxlmem.h > @@ -117,6 +117,7 @@ struct cxl_endpoint_dvsec_info { > * Currently only memory devices are represented. > * > * @dev: The device associated with this CXL state > + * @cxlmd: The device representing the CXL.mem capabilities of @dev > * @regs: Parsed register blocks > * @cxl_dvsec: Offset to the PCIe device DVSEC > * @payload_size: Size of space for payload > @@ -148,6 +149,7 @@ struct cxl_endpoint_dvsec_info { > */ > struct cxl_dev_state { > struct device *dev; > + struct cxl_memdev *cxlmd; This is only used I think to access the cxlmd->dev. Perhaps better to pass the dev and avoid having a reference to the memdev in here? > > struct cxl_regs regs; > int cxl_dvsec; > diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c > index bde8929450f0..823cbfa093fa 100644 > --- a/drivers/cxl/pci.c > +++ b/drivers/cxl/pci.c > @@ -8,6 +8,7 @@ > #include <linux/mutex.h> > #include <linux/list.h> > #include <linux/pci.h> > +#include <linux/aer.h> > #include <linux/io.h> > #include "cxlmem.h" > #include "cxlpci.h" > @@ -533,6 +534,11 @@ static void cxl_dvsec_ranges(struct cxl_dev_state *cxlds) > info->ranges = __cxl_dvsec_ranges(cxlds, info); > } > > +static void disable_aer(void *pdev) > +{ > + pci_disable_pcie_error_reporting(pdev); > +} > + > static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > { > struct cxl_register_map map; > @@ -554,6 +560,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > cxlds = cxl_dev_state_create(&pdev->dev); > if (IS_ERR(cxlds)) > return PTR_ERR(cxlds); > + pci_set_drvdata(pdev, cxlds); > > cxlds->serial = pci_get_dsn(pdev); > cxlds->cxl_dvsec = pci_find_dvsec_capability( > @@ -610,6 +617,14 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > if (IS_ERR(cxlmd)) > return PTR_ERR(cxlmd); > > + if (cxlds->regs.ras) { > + pci_enable_pcie_error_reporting(pdev); > + rc = devm_add_action_or_reset(&pdev->dev, disable_aer, pdev); > + if (rc) > + return rc; > + } > + pci_save_state(pdev); > + > if (range_len(&cxlds->pmem_range) && IS_ENABLED(CONFIG_CXL_PMEM)) > rc = devm_cxl_add_nvdimm(&pdev->dev, cxlmd); > > @@ -623,10 +638,104 @@ static const struct pci_device_id cxl_mem_pci_tbl[] = { > }; > MODULE_DEVICE_TABLE(pci, cxl_mem_pci_tbl); > > +/* > + * Log the state of the RAS status registers and prepare them to log the > + * next error status. > + */ > +static void cxl_report_and_clear(struct cxl_dev_state *cxlds) > +{ > + struct cxl_memdev *cxlmd = cxlds->cxlmd; > + struct device *dev = &cxlmd->dev; > + void __iomem *addr; > + u32 status; > + > + if (!cxlds->regs.ras) > + return; > + > + addr = cxlds->regs.ras + CXL_RAS_UNCORRECTABLE_STATUS_OFFSET; > + status = readl(addr); > + if (status & CXL_RAS_UNCORRECTABLE_STATUS_MASK) { > + dev_warn(cxlds->dev, "%s: uncorrectable status: %#08x\n", > + dev_name(dev), status); > + writel(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK, addr); > + } > + > + addr = cxlds->regs.ras + CXL_RAS_CORRECTABLE_STATUS_OFFSET; > + status = readl(addr); > + if (status & CXL_RAS_CORRECTABLE_STATUS_MASK) { > + dev_warn(cxlds->dev, "%s: correctable status: %#08x\n", > + dev_name(dev), status); > + writel(status & CXL_RAS_CORRECTABLE_STATUS_MASK, addr); > + } > +} > + > +static pci_ers_result_t cxl_error_detected(struct pci_dev *pdev, > + pci_channel_state_t state) > +{ > + struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); > + struct cxl_memdev *cxlmd = cxlds->cxlmd; > + struct device *dev = &cxlmd->dev; Perhaps a more informative name than dev given we have several devs involved here? > + > + /* > + * A frozen channel indicates an impending reset which is fatal to > + * CXL.mem operation, and will likely crash the system. On the off > + * chance the situation is recoverable dump the status of the RAS > + * capability registers and bounce the active state of the memdev. > + */ > + cxl_report_and_clear(cxlds); > + > + switch (state) { > + case pci_channel_io_normal: > + return PCI_ERS_RESULT_CAN_RECOVER; > + case pci_channel_io_frozen: > + dev_warn(&pdev->dev, > + "%s: frozen state error detected, disable CXL.mem\n", > + dev_name(dev)); > + device_release_driver(dev); > + return PCI_ERS_RESULT_NEED_RESET; > + case pci_channel_io_perm_failure: > + dev_warn(&pdev->dev, > + "failure state error detected, request disconnect\n"); > + return PCI_ERS_RESULT_DISCONNECT; > + } > + return PCI_ERS_RESULT_NEED_RESET; > +} > + > +static pci_ers_result_t cxl_slot_reset(struct pci_dev *pdev) > +{ > + struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); > + struct cxl_memdev *cxlmd = cxlds->cxlmd; > + struct device *dev = &cxlmd->dev; > + > + dev_info(&pdev->dev, "%s: restart CXL.mem after slot reset\n", > + dev_name(dev)); > + pci_restore_state(pdev); > + if (device_attach(dev) <= 0) > + return PCI_ERS_RESULT_DISCONNECT; > + return PCI_ERS_RESULT_RECOVERED; > +} > + > +static void cxl_error_resume(struct pci_dev *pdev) > +{ > + struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); > + struct cxl_memdev *cxlmd = cxlds->cxlmd; > + struct device *dev = &cxlmd->dev; > + > + dev_info(&pdev->dev, "%s: error resume %s\n", dev_name(dev), > + dev->driver ? "successful" : "failed"); > +} > + > +static const struct pci_error_handlers cxl_error_handlers = { > + .error_detected = cxl_error_detected, > + .slot_reset = cxl_slot_reset, > + .resume = cxl_error_resume, > +}; > + > static struct pci_driver cxl_pci_driver = { > .name = KBUILD_MODNAME, > .id_table = cxl_mem_pci_tbl, > .probe = cxl_pci_probe, > + .err_handler = &cxl_error_handlers, > .driver = { > .probe_type = PROBE_PREFER_ASYNCHRONOUS, > }, >
Hi Dan, >-----Original Message----- >From: Dan Williams <dan.j.williams@intel.com> >Sent: 16 March 2022 04:14 >To: linux-cxl@vger.kernel.org >Cc: ben.widawsky@intel.com; vishal.l.verma@intel.com; >alison.schofield@intel.com; Jonathan Cameron ><jonathan.cameron@huawei.com>; ira.weiny@intel.com; linux- >pci@vger.kernel.org >Subject: [PATCH 8/8] cxl/pci: Add (hopeful) error handling support > >Add nominal error handling that tears down CXL.mem in response to error >notifications that imply a device reset. Given some CXL.mem may be >operating as System RAM, there is a high likelihood that these error events >are fatal. However, if the system survives the notification the expectation is >that the driver behavior is equivalent to a hot-unplug and re-plug of an >endpoint. > >Note that this does not change the mask values from the default. That awaits >CXL _OSC support to determine whether platform firmware is in control of the >mask registers. > >Signed-off-by: Dan Williams <dan.j.williams@intel.com> >--- > drivers/cxl/core/memdev.c | 1 > drivers/cxl/cxlmem.h | 2 + > drivers/cxl/pci.c | 109 >+++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 112 insertions(+) > >diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c index >1f76b28f9826..223d512790e1 100644 >--- a/drivers/cxl/core/memdev.c >+++ b/drivers/cxl/core/memdev.c >@@ -341,6 +341,7 @@ struct cxl_memdev *devm_cxl_add_memdev(struct >cxl_dev_state *cxlds) > * needed as this is ordered with cdev_add() publishing the device. > */ > cxlmd->cxlds = cxlds; >+ cxlds->cxlmd = cxlmd; > > cdev = &cxlmd->cdev; > rc = cdev_device_add(cdev, dev); >diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h index >5d33ce24fe09..f58e16951414 100644 >--- a/drivers/cxl/cxlmem.h >+++ b/drivers/cxl/cxlmem.h >@@ -117,6 +117,7 @@ struct cxl_endpoint_dvsec_info { > * Currently only memory devices are represented. > * > * @dev: The device associated with this CXL state >+ * @cxlmd: The device representing the CXL.mem capabilities of @dev > * @regs: Parsed register blocks > * @cxl_dvsec: Offset to the PCIe device DVSEC > * @payload_size: Size of space for payload @@ -148,6 +149,7 @@ struct >cxl_endpoint_dvsec_info { > */ > struct cxl_dev_state { > struct device *dev; >+ struct cxl_memdev *cxlmd; > > struct cxl_regs regs; > int cxl_dvsec; >diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c index >bde8929450f0..823cbfa093fa 100644 >--- a/drivers/cxl/pci.c >+++ b/drivers/cxl/pci.c >@@ -8,6 +8,7 @@ > #include <linux/mutex.h> > #include <linux/list.h> > #include <linux/pci.h> >+#include <linux/aer.h> > #include <linux/io.h> > #include "cxlmem.h" > #include "cxlpci.h" >@@ -533,6 +534,11 @@ static void cxl_dvsec_ranges(struct cxl_dev_state >*cxlds) > info->ranges = __cxl_dvsec_ranges(cxlds, info); } > >+static void disable_aer(void *pdev) >+{ >+ pci_disable_pcie_error_reporting(pdev); >+} >+ > static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) >{ > struct cxl_register_map map; >@@ -554,6 +560,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const >struct pci_device_id *id) > cxlds = cxl_dev_state_create(&pdev->dev); > if (IS_ERR(cxlds)) > return PTR_ERR(cxlds); >+ pci_set_drvdata(pdev, cxlds); > > cxlds->serial = pci_get_dsn(pdev); > cxlds->cxl_dvsec = pci_find_dvsec_capability( @@ -610,6 +617,14 @@ >static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > if (IS_ERR(cxlmd)) > return PTR_ERR(cxlmd); > >+ if (cxlds->regs.ras) { >+ pci_enable_pcie_error_reporting(pdev); >+ rc = devm_add_action_or_reset(&pdev->dev, disable_aer, >pdev); >+ if (rc) >+ return rc; >+ } >+ pci_save_state(pdev); >+ > if (range_len(&cxlds->pmem_range) && >IS_ENABLED(CONFIG_CXL_PMEM)) > rc = devm_cxl_add_nvdimm(&pdev->dev, cxlmd); > >@@ -623,10 +638,104 @@ static const struct pci_device_id cxl_mem_pci_tbl[] >= { }; MODULE_DEVICE_TABLE(pci, cxl_mem_pci_tbl); > >+/* >+ * Log the state of the RAS status registers and prepare them to log >+the >+ * next error status. >+ */ >+static void cxl_report_and_clear(struct cxl_dev_state *cxlds) { >+ struct cxl_memdev *cxlmd = cxlds->cxlmd; >+ struct device *dev = &cxlmd->dev; >+ void __iomem *addr; >+ u32 status; >+ >+ if (!cxlds->regs.ras) >+ return; In the cxl_error_detected () may need to return PCI_ERS_RESULT_NONE for the following cases, if exist, 1. if (!cxlds->regs.ras), 2. if any errors would be reported during the dev initialization. >+ >+ addr = cxlds->regs.ras + CXL_RAS_UNCORRECTABLE_STATUS_OFFSET; >+ status = readl(addr); >+ if (status & CXL_RAS_UNCORRECTABLE_STATUS_MASK) { >+ dev_warn(cxlds->dev, "%s: uncorrectable status: %#08x\n", >+ dev_name(dev), status); >+ writel(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK, >addr); >+ } For the uncorrectable non-fatal errors, if any, may need to return PCI_ERS_RESULT_NEED_RESET to trigger the slot reset to prevent more serious issues later. For this case the state would be "pci_channel_io_normal". >+ >+ addr = cxlds->regs.ras + CXL_RAS_CORRECTABLE_STATUS_OFFSET; >+ status = readl(addr); >+ if (status & CXL_RAS_CORRECTABLE_STATUS_MASK) { >+ dev_warn(cxlds->dev, "%s: correctable status: %#08x\n", >+ dev_name(dev), status); >+ writel(status & CXL_RAS_CORRECTABLE_STATUS_MASK, >addr); >+ } >+} >+ >+static pci_ers_result_t cxl_error_detected(struct pci_dev *pdev, >+ pci_channel_state_t state) >+{ >+ struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); >+ struct cxl_memdev *cxlmd = cxlds->cxlmd; >+ struct device *dev = &cxlmd->dev; >+ >+ /* >+ * A frozen channel indicates an impending reset which is fatal to >+ * CXL.mem operation, and will likely crash the system. On the off >+ * chance the situation is recoverable dump the status of the RAS >+ * capability registers and bounce the active state of the memdev. >+ */ >+ cxl_report_and_clear(cxlds); >+ >+ switch (state) { >+ case pci_channel_io_normal: >+ return PCI_ERS_RESULT_CAN_RECOVER; >+ case pci_channel_io_frozen: >+ dev_warn(&pdev->dev, >+ "%s: frozen state error detected, disable >CXL.mem\n", >+ dev_name(dev)); >+ device_release_driver(dev); >+ return PCI_ERS_RESULT_NEED_RESET; >+ case pci_channel_io_perm_failure: >+ dev_warn(&pdev->dev, >+ "failure state error detected, request disconnect\n"); >+ return PCI_ERS_RESULT_DISCONNECT; >+ } >+ return PCI_ERS_RESULT_NEED_RESET; >+} >+ >+static pci_ers_result_t cxl_slot_reset(struct pci_dev *pdev) { >+ struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); >+ struct cxl_memdev *cxlmd = cxlds->cxlmd; >+ struct device *dev = &cxlmd->dev; >+ >+ dev_info(&pdev->dev, "%s: restart CXL.mem after slot reset\n", >+ dev_name(dev)); >+ pci_restore_state(pdev); 1. Do we need to call pci_save_state(pdev) here after the reset? though pci_save_state(pdev) is being invoked in the cxl_pci_probe(). >+ if (device_attach(dev) <= 0) >+ return PCI_ERS_RESULT_DISCONNECT; My understanding is that pci_disable_pcie_error_reporting(pdev) would be called in the disable_aer () in the reset, pci_enable_pcie_error_reporting(pdev) may need to call here after the reset? >+ return PCI_ERS_RESULT_RECOVERED; >+} >+ >+static void cxl_error_resume(struct pci_dev *pdev) { >+ struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); >+ struct cxl_memdev *cxlmd = cxlds->cxlmd; >+ struct device *dev = &cxlmd->dev; >+ >+ dev_info(&pdev->dev, "%s: error resume %s\n", dev_name(dev), >+ dev->driver ? "successful" : "failed"); } >+ >+static const struct pci_error_handlers cxl_error_handlers = { >+ .error_detected = cxl_error_detected, >+ .slot_reset = cxl_slot_reset, >+ .resume = cxl_error_resume, If the FLR (Function level reset) supported, please add the corresponding callback functions reset_prepare(..) and reset_done(..). >+}; >+ > static struct pci_driver cxl_pci_driver = { > .name = KBUILD_MODNAME, > .id_table = cxl_mem_pci_tbl, > .probe = cxl_pci_probe, >+ .err_handler = &cxl_error_handlers, > .driver = { > .probe_type = PROBE_PREFER_ASYNCHRONOUS, > }, Thanks, Shiju
On Fri, Mar 18, 2022 at 2:42 AM Shiju Jose <shiju.jose@huawei.com> wrote: > > Hi Dan, Hi, thanks for taking a look at this. > > >-----Original Message----- > >From: Dan Williams <dan.j.williams@intel.com> > >Sent: 16 March 2022 04:14 > >To: linux-cxl@vger.kernel.org > >Cc: ben.widawsky@intel.com; vishal.l.verma@intel.com; > >alison.schofield@intel.com; Jonathan Cameron > ><jonathan.cameron@huawei.com>; ira.weiny@intel.com; linux- > >pci@vger.kernel.org > >Subject: [PATCH 8/8] cxl/pci: Add (hopeful) error handling support > > > >Add nominal error handling that tears down CXL.mem in response to error > >notifications that imply a device reset. Given some CXL.mem may be > >operating as System RAM, there is a high likelihood that these error events > >are fatal. However, if the system survives the notification the expectation is > >that the driver behavior is equivalent to a hot-unplug and re-plug of an > >endpoint. > > > >Note that this does not change the mask values from the default. That awaits > >CXL _OSC support to determine whether platform firmware is in control of the > >mask registers. > > > >Signed-off-by: Dan Williams <dan.j.williams@intel.com> > >--- > > drivers/cxl/core/memdev.c | 1 > > drivers/cxl/cxlmem.h | 2 + > > drivers/cxl/pci.c | 109 > >+++++++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 112 insertions(+) > > > >diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c index > >1f76b28f9826..223d512790e1 100644 > >--- a/drivers/cxl/core/memdev.c > >+++ b/drivers/cxl/core/memdev.c > >@@ -341,6 +341,7 @@ struct cxl_memdev *devm_cxl_add_memdev(struct > >cxl_dev_state *cxlds) > > * needed as this is ordered with cdev_add() publishing the device. > > */ > > cxlmd->cxlds = cxlds; > >+ cxlds->cxlmd = cxlmd; > > > > cdev = &cxlmd->cdev; > > rc = cdev_device_add(cdev, dev); > >diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h index > >5d33ce24fe09..f58e16951414 100644 > >--- a/drivers/cxl/cxlmem.h > >+++ b/drivers/cxl/cxlmem.h > >@@ -117,6 +117,7 @@ struct cxl_endpoint_dvsec_info { > > * Currently only memory devices are represented. > > * > > * @dev: The device associated with this CXL state > >+ * @cxlmd: The device representing the CXL.mem capabilities of @dev > > * @regs: Parsed register blocks > > * @cxl_dvsec: Offset to the PCIe device DVSEC > > * @payload_size: Size of space for payload @@ -148,6 +149,7 @@ struct > >cxl_endpoint_dvsec_info { > > */ > > struct cxl_dev_state { > > struct device *dev; > >+ struct cxl_memdev *cxlmd; > > > > struct cxl_regs regs; > > int cxl_dvsec; > >diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c index > >bde8929450f0..823cbfa093fa 100644 > >--- a/drivers/cxl/pci.c > >+++ b/drivers/cxl/pci.c > >@@ -8,6 +8,7 @@ > > #include <linux/mutex.h> > > #include <linux/list.h> > > #include <linux/pci.h> > >+#include <linux/aer.h> > > #include <linux/io.h> > > #include "cxlmem.h" > > #include "cxlpci.h" > >@@ -533,6 +534,11 @@ static void cxl_dvsec_ranges(struct cxl_dev_state > >*cxlds) > > info->ranges = __cxl_dvsec_ranges(cxlds, info); } > > > >+static void disable_aer(void *pdev) > >+{ > >+ pci_disable_pcie_error_reporting(pdev); > >+} > >+ > > static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > >{ > > struct cxl_register_map map; > >@@ -554,6 +560,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const > >struct pci_device_id *id) > > cxlds = cxl_dev_state_create(&pdev->dev); > > if (IS_ERR(cxlds)) > > return PTR_ERR(cxlds); > >+ pci_set_drvdata(pdev, cxlds); > > > > cxlds->serial = pci_get_dsn(pdev); > > cxlds->cxl_dvsec = pci_find_dvsec_capability( @@ -610,6 +617,14 @@ > >static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > > if (IS_ERR(cxlmd)) > > return PTR_ERR(cxlmd); > > > >+ if (cxlds->regs.ras) { > >+ pci_enable_pcie_error_reporting(pdev); > >+ rc = devm_add_action_or_reset(&pdev->dev, disable_aer, > >pdev); > >+ if (rc) > >+ return rc; > >+ } > >+ pci_save_state(pdev); > >+ > > if (range_len(&cxlds->pmem_range) && > >IS_ENABLED(CONFIG_CXL_PMEM)) > > rc = devm_cxl_add_nvdimm(&pdev->dev, cxlmd); > > > >@@ -623,10 +638,104 @@ static const struct pci_device_id cxl_mem_pci_tbl[] > >= { }; MODULE_DEVICE_TABLE(pci, cxl_mem_pci_tbl); > > > >+/* > >+ * Log the state of the RAS status registers and prepare them to log > >+the > >+ * next error status. > >+ */ > >+static void cxl_report_and_clear(struct cxl_dev_state *cxlds) { > >+ struct cxl_memdev *cxlmd = cxlds->cxlmd; > >+ struct device *dev = &cxlmd->dev; > >+ void __iomem *addr; > >+ u32 status; > >+ > >+ if (!cxlds->regs.ras) > >+ return; > In the cxl_error_detected () may need to return PCI_ERS_RESULT_NONE > for the following cases, if exist, > 1. if (!cxlds->regs.ras), Yes, but given that the RAS capability is mandatory for CXL devices then I think the driver should just fail to register altogether if the RAS register are not found / mapped. > 2. if any errors would be reported during the dev initialization. This can't happen. The err_handler callback process takes the device_lock() which ensures that any initialization that has started completes before the callback is invoked. > > >+ > >+ addr = cxlds->regs.ras + CXL_RAS_UNCORRECTABLE_STATUS_OFFSET; > >+ status = readl(addr); > >+ if (status & CXL_RAS_UNCORRECTABLE_STATUS_MASK) { > >+ dev_warn(cxlds->dev, "%s: uncorrectable status: %#08x\n", > >+ dev_name(dev), status); > >+ writel(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK, > >addr); > >+ } > For the uncorrectable non-fatal errors, if any, may need to return PCI_ERS_RESULT_NEED_RESET > to trigger the slot reset to prevent more serious issues later. For this case the state would be > "pci_channel_io_normal". > Ah true, some pci_channel_io_normal recovery conditions still result in reset, will fix. > >+ > >+ addr = cxlds->regs.ras + CXL_RAS_CORRECTABLE_STATUS_OFFSET; > >+ status = readl(addr); > >+ if (status & CXL_RAS_CORRECTABLE_STATUS_MASK) { > >+ dev_warn(cxlds->dev, "%s: correctable status: %#08x\n", > >+ dev_name(dev), status); > >+ writel(status & CXL_RAS_CORRECTABLE_STATUS_MASK, > >addr); > >+ } > >+} > >+ > >+static pci_ers_result_t cxl_error_detected(struct pci_dev *pdev, > >+ pci_channel_state_t state) > >+{ > >+ struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); > >+ struct cxl_memdev *cxlmd = cxlds->cxlmd; > >+ struct device *dev = &cxlmd->dev; > >+ > >+ /* > >+ * A frozen channel indicates an impending reset which is fatal to > >+ * CXL.mem operation, and will likely crash the system. On the off > >+ * chance the situation is recoverable dump the status of the RAS > >+ * capability registers and bounce the active state of the memdev. > >+ */ > >+ cxl_report_and_clear(cxlds); > >+ > >+ switch (state) { > >+ case pci_channel_io_normal: > >+ return PCI_ERS_RESULT_CAN_RECOVER; > >+ case pci_channel_io_frozen: > >+ dev_warn(&pdev->dev, > >+ "%s: frozen state error detected, disable > >CXL.mem\n", > >+ dev_name(dev)); > >+ device_release_driver(dev); > >+ return PCI_ERS_RESULT_NEED_RESET; > >+ case pci_channel_io_perm_failure: > >+ dev_warn(&pdev->dev, > >+ "failure state error detected, request disconnect\n"); > >+ return PCI_ERS_RESULT_DISCONNECT; > >+ } > >+ return PCI_ERS_RESULT_NEED_RESET; > >+} > >+ > >+static pci_ers_result_t cxl_slot_reset(struct pci_dev *pdev) { > >+ struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); > >+ struct cxl_memdev *cxlmd = cxlds->cxlmd; > >+ struct device *dev = &cxlmd->dev; > >+ > >+ dev_info(&pdev->dev, "%s: restart CXL.mem after slot reset\n", > >+ dev_name(dev)); > >+ pci_restore_state(pdev); > 1. Do we need to call pci_save_state(pdev) here after the reset? though pci_save_state(pdev) is being invoked in the > cxl_pci_probe(). The save state after probe is sufficient, it does not need to be snapshotted again as far as I can see. > > >+ if (device_attach(dev) <= 0) > >+ return PCI_ERS_RESULT_DISCONNECT; > My understanding is that pci_disable_pcie_error_reporting(pdev) would be called > in the disable_aer () in the reset, > pci_enable_pcie_error_reporting(pdev) may need to call here after the reset? After the device is disconnected the driver needs to be reloaded to recover AER operation. > > >+ return PCI_ERS_RESULT_RECOVERED; > >+} > >+ > >+static void cxl_error_resume(struct pci_dev *pdev) { > >+ struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); > >+ struct cxl_memdev *cxlmd = cxlds->cxlmd; > >+ struct device *dev = &cxlmd->dev; > >+ > >+ dev_info(&pdev->dev, "%s: error resume %s\n", dev_name(dev), > >+ dev->driver ? "successful" : "failed"); } > >+ > >+static const struct pci_error_handlers cxl_error_handlers = { > >+ .error_detected = cxl_error_detected, > >+ .slot_reset = cxl_slot_reset, > >+ .resume = cxl_error_resume, > If the FLR (Function level reset) supported, please add the corresponding callback functions > reset_prepare(..) and reset_done(..). No, FLR does not recover any of the errors reported via AER. > > >+}; > >+ > > static struct pci_driver cxl_pci_driver = { > > .name = KBUILD_MODNAME, > > .id_table = cxl_mem_pci_tbl, > > .probe = cxl_pci_probe, > >+ .err_handler = &cxl_error_handlers, > > .driver = { > > .probe_type = PROBE_PREFER_ASYNCHRONOUS, > > }, > > > Thanks, > Shiju
diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c index 1f76b28f9826..223d512790e1 100644 --- a/drivers/cxl/core/memdev.c +++ b/drivers/cxl/core/memdev.c @@ -341,6 +341,7 @@ struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds) * needed as this is ordered with cdev_add() publishing the device. */ cxlmd->cxlds = cxlds; + cxlds->cxlmd = cxlmd; cdev = &cxlmd->cdev; rc = cdev_device_add(cdev, dev); diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h index 5d33ce24fe09..f58e16951414 100644 --- a/drivers/cxl/cxlmem.h +++ b/drivers/cxl/cxlmem.h @@ -117,6 +117,7 @@ struct cxl_endpoint_dvsec_info { * Currently only memory devices are represented. * * @dev: The device associated with this CXL state + * @cxlmd: The device representing the CXL.mem capabilities of @dev * @regs: Parsed register blocks * @cxl_dvsec: Offset to the PCIe device DVSEC * @payload_size: Size of space for payload @@ -148,6 +149,7 @@ struct cxl_endpoint_dvsec_info { */ struct cxl_dev_state { struct device *dev; + struct cxl_memdev *cxlmd; struct cxl_regs regs; int cxl_dvsec; diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c index bde8929450f0..823cbfa093fa 100644 --- a/drivers/cxl/pci.c +++ b/drivers/cxl/pci.c @@ -8,6 +8,7 @@ #include <linux/mutex.h> #include <linux/list.h> #include <linux/pci.h> +#include <linux/aer.h> #include <linux/io.h> #include "cxlmem.h" #include "cxlpci.h" @@ -533,6 +534,11 @@ static void cxl_dvsec_ranges(struct cxl_dev_state *cxlds) info->ranges = __cxl_dvsec_ranges(cxlds, info); } +static void disable_aer(void *pdev) +{ + pci_disable_pcie_error_reporting(pdev); +} + static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) { struct cxl_register_map map; @@ -554,6 +560,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) cxlds = cxl_dev_state_create(&pdev->dev); if (IS_ERR(cxlds)) return PTR_ERR(cxlds); + pci_set_drvdata(pdev, cxlds); cxlds->serial = pci_get_dsn(pdev); cxlds->cxl_dvsec = pci_find_dvsec_capability( @@ -610,6 +617,14 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) if (IS_ERR(cxlmd)) return PTR_ERR(cxlmd); + if (cxlds->regs.ras) { + pci_enable_pcie_error_reporting(pdev); + rc = devm_add_action_or_reset(&pdev->dev, disable_aer, pdev); + if (rc) + return rc; + } + pci_save_state(pdev); + if (range_len(&cxlds->pmem_range) && IS_ENABLED(CONFIG_CXL_PMEM)) rc = devm_cxl_add_nvdimm(&pdev->dev, cxlmd); @@ -623,10 +638,104 @@ static const struct pci_device_id cxl_mem_pci_tbl[] = { }; MODULE_DEVICE_TABLE(pci, cxl_mem_pci_tbl); +/* + * Log the state of the RAS status registers and prepare them to log the + * next error status. + */ +static void cxl_report_and_clear(struct cxl_dev_state *cxlds) +{ + struct cxl_memdev *cxlmd = cxlds->cxlmd; + struct device *dev = &cxlmd->dev; + void __iomem *addr; + u32 status; + + if (!cxlds->regs.ras) + return; + + addr = cxlds->regs.ras + CXL_RAS_UNCORRECTABLE_STATUS_OFFSET; + status = readl(addr); + if (status & CXL_RAS_UNCORRECTABLE_STATUS_MASK) { + dev_warn(cxlds->dev, "%s: uncorrectable status: %#08x\n", + dev_name(dev), status); + writel(status & CXL_RAS_UNCORRECTABLE_STATUS_MASK, addr); + } + + addr = cxlds->regs.ras + CXL_RAS_CORRECTABLE_STATUS_OFFSET; + status = readl(addr); + if (status & CXL_RAS_CORRECTABLE_STATUS_MASK) { + dev_warn(cxlds->dev, "%s: correctable status: %#08x\n", + dev_name(dev), status); + writel(status & CXL_RAS_CORRECTABLE_STATUS_MASK, addr); + } +} + +static pci_ers_result_t cxl_error_detected(struct pci_dev *pdev, + pci_channel_state_t state) +{ + struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); + struct cxl_memdev *cxlmd = cxlds->cxlmd; + struct device *dev = &cxlmd->dev; + + /* + * A frozen channel indicates an impending reset which is fatal to + * CXL.mem operation, and will likely crash the system. On the off + * chance the situation is recoverable dump the status of the RAS + * capability registers and bounce the active state of the memdev. + */ + cxl_report_and_clear(cxlds); + + switch (state) { + case pci_channel_io_normal: + return PCI_ERS_RESULT_CAN_RECOVER; + case pci_channel_io_frozen: + dev_warn(&pdev->dev, + "%s: frozen state error detected, disable CXL.mem\n", + dev_name(dev)); + device_release_driver(dev); + return PCI_ERS_RESULT_NEED_RESET; + case pci_channel_io_perm_failure: + dev_warn(&pdev->dev, + "failure state error detected, request disconnect\n"); + return PCI_ERS_RESULT_DISCONNECT; + } + return PCI_ERS_RESULT_NEED_RESET; +} + +static pci_ers_result_t cxl_slot_reset(struct pci_dev *pdev) +{ + struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); + struct cxl_memdev *cxlmd = cxlds->cxlmd; + struct device *dev = &cxlmd->dev; + + dev_info(&pdev->dev, "%s: restart CXL.mem after slot reset\n", + dev_name(dev)); + pci_restore_state(pdev); + if (device_attach(dev) <= 0) + return PCI_ERS_RESULT_DISCONNECT; + return PCI_ERS_RESULT_RECOVERED; +} + +static void cxl_error_resume(struct pci_dev *pdev) +{ + struct cxl_dev_state *cxlds = pci_get_drvdata(pdev); + struct cxl_memdev *cxlmd = cxlds->cxlmd; + struct device *dev = &cxlmd->dev; + + dev_info(&pdev->dev, "%s: error resume %s\n", dev_name(dev), + dev->driver ? "successful" : "failed"); +} + +static const struct pci_error_handlers cxl_error_handlers = { + .error_detected = cxl_error_detected, + .slot_reset = cxl_slot_reset, + .resume = cxl_error_resume, +}; + static struct pci_driver cxl_pci_driver = { .name = KBUILD_MODNAME, .id_table = cxl_mem_pci_tbl, .probe = cxl_pci_probe, + .err_handler = &cxl_error_handlers, .driver = { .probe_type = PROBE_PREFER_ASYNCHRONOUS, },
Add nominal error handling that tears down CXL.mem in response to error notifications that imply a device reset. Given some CXL.mem may be operating as System RAM, there is a high likelihood that these error events are fatal. However, if the system survives the notification the expectation is that the driver behavior is equivalent to a hot-unplug and re-plug of an endpoint. Note that this does not change the mask values from the default. That awaits CXL _OSC support to determine whether platform firmware is in control of the mask registers. Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- drivers/cxl/core/memdev.c | 1 drivers/cxl/cxlmem.h | 2 + drivers/cxl/pci.c | 109 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 112 insertions(+)