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Message-ID: <c1837324-98b0-4548-893f-b14e89ced9db@linux.intel.com>
Date: Tue, 11 Feb 2025 13:23:30 -0800
From: Sathyanarayanan Kuppuswamy <sathyanarayanan.kuppuswamy@...ux.intel.com>
To: Shuai Xue <xueshuai@...ux.alibaba.com>, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
bhelgaas@...gle.com, kbusch@...nel.org
Cc: mahesh@...ux.ibm.com, oohall@...il.com, Jonathan.Cameron@...wei.com,
terry.bowman@....com
Subject: Re: [PATCH v3 3/4] PCI/DPC: Run recovery on device that detected the
error
On 2/7/25 1:34 AM, Shuai Xue wrote:
> The current implementation of pcie_do_recovery() assumes that the
> recovery process is executed on the device that detected the error.
> However, the DPC driver currently passes the error port that experienced
> the DPC event to pcie_do_recovery().
>
> Use the SOURCE ID register to correctly identify the device that detected the
> error. By passing this error device to pcie_do_recovery(), subsequent
> patches will be able to accurately access AER status of the error device.
I also recommend adding info about the fact that pcie_do_recovery() finds
upstream bridge to run the recovery process and hence should not observe
any functional changes (compared to previous version)
>
> Signed-off-by: Shuai Xue <xueshuai@...ux.alibaba.com>
> ---
> drivers/pci/pci.h | 2 +-
> drivers/pci/pcie/dpc.c | 25 +++++++++++++++++++++----
> drivers/pci/pcie/edr.c | 7 ++++---
> 3 files changed, 26 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 01e51db8d285..870d2fbd6ff2 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -572,7 +572,7 @@ struct rcec_ea {
> void pci_save_dpc_state(struct pci_dev *dev);
> void pci_restore_dpc_state(struct pci_dev *dev);
> void pci_dpc_init(struct pci_dev *pdev);
> -void dpc_process_error(struct pci_dev *pdev);
> +struct pci_dev *dpc_process_error(struct pci_dev *pdev);
> pci_ers_result_t dpc_reset_link(struct pci_dev *pdev);
> bool pci_dpc_recovered(struct pci_dev *pdev);
> unsigned int dpc_tlp_log_len(struct pci_dev *dev);
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index 1a54a0b657ae..a91440f3b118 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -253,10 +253,17 @@ static int dpc_get_aer_uncorrect_severity(struct pci_dev *dev,
> return 1;
> }
>
> -void dpc_process_error(struct pci_dev *pdev)
> +/**
> + * dpc_process_error - handle the DPC error status
> + * @pdev: the port that experienced the containment event
> + *
> + * Return the device that detected the error.
> + */
Add a note about calling pci_dev_put() after using this function.
> +struct pci_dev *dpc_process_error(struct pci_dev *pdev)
> {
> u16 cap = pdev->dpc_cap, status, source, reason, ext_reason;
> struct aer_err_info info;
> + struct pci_dev *err_dev;
>
> pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
> pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &source);
> @@ -279,6 +286,13 @@ void dpc_process_error(struct pci_dev *pdev)
> "software trigger" :
> "reserved error");
>
> + if (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_NFE ||
> + reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_FE)
> + err_dev = pci_get_domain_bus_and_slot(pci_domain_nr(pdev->bus),
> + PCI_BUS_NUM(source), source & 0xff);
> + else
> + err_dev = pci_dev_get(pdev);
> +
> /* show RP PIO error detail information */
> if (pdev->dpc_rp_extensions &&
> reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_IN_EXT &&
> @@ -291,6 +305,8 @@ void dpc_process_error(struct pci_dev *pdev)
> pci_aer_clear_nonfatal_status(pdev);
> pci_aer_clear_fatal_status(pdev);
> }
> +
> + return err_dev;
> }
>
> static void pci_clear_surpdn_errors(struct pci_dev *pdev)
> @@ -346,7 +362,7 @@ static bool dpc_is_surprise_removal(struct pci_dev *pdev)
>
> static irqreturn_t dpc_handler(int irq, void *context)
> {
> - struct pci_dev *err_port = context;
> + struct pci_dev *err_port = context, *err_dev;
>
> /*
> * According to PCIe r6.0 sec 6.7.6, errors are an expected side effect
> @@ -357,10 +373,11 @@ static irqreturn_t dpc_handler(int irq, void *context)
> return IRQ_HANDLED;
> }
>
> - dpc_process_error(err_port);
> + err_dev = dpc_process_error(err_port);
>
> /* We configure DPC so it only triggers on ERR_FATAL */
> - pcie_do_recovery(err_port, pci_channel_io_frozen, dpc_reset_link);
> + pcie_do_recovery(err_dev, pci_channel_io_frozen, dpc_reset_link);
> + pci_dev_put(err_dev);
>
> return IRQ_HANDLED;
> }
> diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c
> index 521fca2f40cb..088f3e188f54 100644
> --- a/drivers/pci/pcie/edr.c
> +++ b/drivers/pci/pcie/edr.c
> @@ -150,7 +150,7 @@ static int acpi_send_edr_status(struct pci_dev *pdev, struct pci_dev *edev,
>
> static void edr_handle_event(acpi_handle handle, u32 event, void *data)
> {
> - struct pci_dev *pdev = data, *err_port;
> + struct pci_dev *pdev = data, *err_port, *err_dev;
> pci_ers_result_t estate = PCI_ERS_RESULT_DISCONNECT;
> u16 status;
>
> @@ -190,7 +190,7 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data)
> goto send_ost;
> }
>
> - dpc_process_error(err_port);
> + err_dev = dpc_process_error(err_port);
> pci_aer_raw_clear_status(err_port);
>
> /*
> @@ -198,7 +198,7 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data)
> * or ERR_NONFATAL, since the link is already down, use the FATAL
> * error recovery path for both cases.
> */
> - estate = pcie_do_recovery(err_port, pci_channel_io_frozen, dpc_reset_link);
> + estate = pcie_do_recovery(err_dev, pci_channel_io_frozen, dpc_reset_link);
>
> send_ost:
>
> @@ -216,6 +216,7 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data)
> }
>
> pci_dev_put(err_port);
> + pci_dev_put(err_dev);
> }
>
> void pci_acpi_add_edr_notifier(struct pci_dev *pdev)
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer
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