linux-kernel - Re: [PATCH v4 5/5] acpi/ghes, cxl/pci: Process CXL CPER Protocol Errors

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Message-ID: <2e37e889-ee70-48a2-8d3c-379e66a4519d@amd.com>
Date: Thu, 2 Jan 2025 11:56:04 -0800
From: "Koralahalli Channabasappa, Smita"
 <Smita.KoralahalliChannabasappa@....com>
To: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Cc: linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-cxl@...r.kernel.org, Ard Biesheuvel <ardb@...nel.org>,
 Alison Schofield <alison.schofield@...el.com>,
 Vishal Verma <vishal.l.verma@...el.com>, Ira Weiny <ira.weiny@...el.com>,
 Dan Williams <dan.j.williams@...el.com>,
 Yazen Ghannam <yazen.ghannam@....com>, Terry Bowman <terry.bowman@....com>
Subject: Re: [PATCH v4 5/5] acpi/ghes, cxl/pci: Process CXL CPER Protocol
 Errors

On 12/24/2024 10:14 AM, Jonathan Cameron wrote:
> On Tue, 17 Dec 2024 02:20:32 +0000
> Smita Koralahalli <Smita.KoralahalliChannabasappa@....com> wrote:
> 
>> When PCIe AER is in FW-First, OS should process CXL Protocol errors from
>> CPER records. Introduce support for handling and logging CXL Protocol
>> errors.
>>
>> The defined trace events cxl_aer_uncorrectable_error and
>> cxl_aer_correctable_error trace native CXL AER endpoint errors, while
>> cxl_cper_trace_corr_prot_err and cxl_cper_trace_uncorr_prot_err
>> trace native CXL AER port errors. Reuse both sets to trace FW-First
>> protocol errors.
>>
>> Since the CXL code is required to be called from process context and
>> GHES is in interrupt context, use workqueues for processing.
>>
>> Similar to CXL CPER event handling, use kfifo to handle errors as it
>> simplifies queue processing by providing lock free fifo operations.
>>
>> Add the ability for the CXL sub-system to register a workqueue to
>> process CXL CPER protocol errors.
>>
>> Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>
> 
> Hi Smita,
> 
> A few really minor thing inline. Main one is this needs a rebase
> as the EXPORT_SYMBOL_NS_GPL() macros changed just after rc1
> to require quoted strings.

Okay. I will rebase and remove blank line.

Thanks
Smita

> 
>>   #define CXL_CPER_FIFO_DEPTH 32
>> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
>> index 740ac5d8809f..5bad24965e24 100644
>> --- a/drivers/cxl/core/pci.c
>> +++ b/drivers/cxl/core/pci.c
>> @@ -650,6 +650,68 @@ void read_cdat_data(struct cxl_port *port)
>>   }
>>   EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);
> 
>> +EXPORT_SYMBOL_NS_GPL(cxl_cper_trace_uncorr_prot_err, CXL);
> Needs a rebase on rc2 or later.  "CXL" - quotes now needed.
> 
> 
> 
>> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
>> index 188412d45e0d..f6d467cd9232 100644
>> --- a/drivers/cxl/pci.c
>> +++ b/drivers/cxl/pci.c
>> @@ -1067,6 +1067,51 @@ static void cxl_cper_work_fn(struct work_struct *work)
>>   }
>>   static DECLARE_WORK(cxl_cper_work, cxl_cper_work_fn);
>>   
>> +static void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data *data)
>> +{
>> +	unsigned int devfn = PCI_DEVFN(data->prot_err.agent_addr.device,
>> +				       data->prot_err.agent_addr.function);
>> +	struct pci_dev *pdev __free(pci_dev_put) =
>> +		pci_get_domain_bus_and_slot(data->prot_err.agent_addr.segment,
>> +					    data->prot_err.agent_addr.bus,
>> +					    devfn);
>> +	int port_type;
>> +
>> +	if (!pdev)
>> +		return;
>> +
>> +	guard(device)(&pdev->dev);
>> +	if (pdev->driver != &cxl_pci_driver)
>> +		return;
>> +
>> +	port_type = pci_pcie_type(pdev);
>> +	if (port_type == PCI_EXP_TYPE_ROOT_PORT ||
>> +	    port_type == PCI_EXP_TYPE_DOWNSTREAM ||
>> +	    port_type == PCI_EXP_TYPE_UPSTREAM) {
>> +		if (data->severity == AER_CORRECTABLE)
>> +			cxl_cper_trace_corr_port_prot_err(pdev, data->ras_cap);
>> +		else
>> +			cxl_cper_trace_uncorr_port_prot_err(pdev, data->ras_cap);
>> +
>> +		return;
>> +	}
>> +
>> +	if (data->severity == AER_CORRECTABLE)
>> +		cxl_cper_trace_corr_prot_err(pdev, data->ras_cap);
>> +	else
>> +		cxl_cper_trace_uncorr_prot_err(pdev, data->ras_cap);
>> +
> No need for this blank line.
> 
>> +}