Re: [PATCH v2 3/4] acpi/ghes, efi/cper: Recognize and process CXL Protocol Errors.

[Fan Ni <nifan.cxl@gmail.com>]

On Tue, Oct 01, 2024 at 12:52:33AM +0000, Smita Koralahalli wrote:
> UEFI v2.10 section N.2.13 defines a CPER record for CXL Protocol errors.
> 
> Add GHES support to detect CXL CPER Protocol Error Record and Cache Error
> Severity, Device ID, Device Serial number and CXL RAS capability struct in
> struct cxl_cper_prot_err. Include this struct as a member of struct
> cxl_cper_work_data.
> 
> Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
> ---
> v2:
> 	Defined array of structures for Device ID and Serial number
> 	comparison.
> 	p_err -> rec/p_rec.
> ---
>  drivers/acpi/apei/ghes.c        |  10 +++
>  drivers/firmware/efi/cper_cxl.c | 115 ++++++++++++++++++++++++++++++++
>  include/cxl/event.h             |  26 ++++++++
>  3 files changed, 151 insertions(+)
> 
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index ada93cfde9ba..9dcf0f78458f 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -717,6 +717,14 @@ static void cxl_cper_post_event(enum cxl_event_type event_type,
>  	schedule_work(cxl_cper_work);
>  }
>  
> +static void cxl_cper_handle_prot_err(struct acpi_hest_generic_data *gdata)
> +{
> +	struct cxl_cper_work_data wd;
> +
> +	if (cxl_cper_handle_prot_err_info(gdata, &wd.p_rec))
> +		return;
> +}

Why we need a if here? It seems the function will return anyway.

Fan
> +
>  int cxl_cper_register_work(struct work_struct *work)
>  {
>  	if (cxl_cper_work)
> @@ -791,6 +799,8 @@ static bool ghes_do_proc(struct ghes *ghes,
>  			struct cxl_cper_event_rec *rec = acpi_hest_get_payload(gdata);
>  
>  			cxl_cper_post_event(CXL_CPER_EVENT_MEM_MODULE, rec);
> +		} else if (guid_equal(sec_type, &CPER_SEC_CXL_PROT_ERR)) {
> +			cxl_cper_handle_prot_err(gdata);
>  		} else {
>  			void *err = acpi_hest_get_payload(gdata);
>  
> diff --git a/drivers/firmware/efi/cper_cxl.c b/drivers/firmware/efi/cper_cxl.c
> index 4fd8d783993e..08da7764c066 100644
> --- a/drivers/firmware/efi/cper_cxl.c
> +++ b/drivers/firmware/efi/cper_cxl.c
> @@ -8,6 +8,7 @@
>   */
>  
>  #include <linux/cper.h>
> +#include <acpi/ghes.h>
>  #include "cper_cxl.h"
>  
>  #define PROT_ERR_VALID_AGENT_TYPE		BIT_ULL(0)
> @@ -44,6 +45,66 @@ enum {
>  	USP,	/* CXL Upstream Switch Port */
>  };
>  
> +struct agent_info {
> +	const char *string;
> +	bool req_sn;
> +	bool req_sbdf;
> +};
> +
> +static const struct agent_info agent_info[] = {
> +	[RCD] = {
> +		.string = "Restricted CXL Device",
> +		.req_sbdf = true,
> +		.req_sn = true,
> +	},
> +	[RCH_DP] = {
> +		.string = "Restricted CXL Host Downstream Port",
> +		.req_sbdf = false,
> +		.req_sn = false,
> +	},
> +	[DEVICE] = {
> +		.string = "CXL Device",
> +		.req_sbdf = true,
> +		.req_sn = true,
> +	},
> +	[LD] = {
> +		.string = "CXL Logical Device",
> +		.req_sbdf = true,
> +		.req_sn = true,
> +	},
> +	[FMLD] = {
> +		.string = "CXL Fabric Manager managed Logical Device",
> +		.req_sbdf = true,
> +		.req_sn = true,
> +	},
> +	[RP] = {
> +		.string = "CXL Root Port",
> +		.req_sbdf = true,
> +		.req_sn = false,
> +	},
> +	[DSP] = {
> +		.string = "CXL Downstream Switch Port",
> +		.req_sbdf = true,
> +		.req_sn = false,
> +	},
> +	[USP] = {
> +		.string = "CXL Upstream Switch Port",
> +		.req_sbdf = true,
> +		.req_sn = false,
> +	},
> +};
> +
> +static enum cxl_aer_err_type cper_severity_cxl_aer(int cper_severity)
> +{
> +	switch (cper_severity) {
> +	case CPER_SEV_RECOVERABLE:
> +	case CPER_SEV_FATAL:
> +		return CXL_AER_UNCORRECTABLE;
> +	default:
> +		return CXL_AER_CORRECTABLE;
> +	}
> +}
> +
>  void cper_print_prot_err(const char *pfx, const struct cper_sec_prot_err *prot_err)
>  {
>  	if (prot_err->valid_bits & PROT_ERR_VALID_AGENT_TYPE)
> @@ -176,3 +237,57 @@ void cper_print_prot_err(const char *pfx, const struct cper_sec_prot_err *prot_e
>  			       sizeof(cxl_ras->header_log), 0);
>  	}
>  }
> +
> +int cxl_cper_handle_prot_err_info(struct acpi_hest_generic_data *gdata,
> +				  struct cxl_cper_prot_err *rec)
> +{
> +	struct cper_sec_prot_err *prot_err = acpi_hest_get_payload(gdata);
> +	u8 *dvsec_start, *cap_start;
> +
> +	if (!(prot_err->valid_bits & PROT_ERR_VALID_DEVICE_ID)) {
> +		pr_err(FW_WARN "No Device ID\n");
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * The device ID or agent address is required for CXL RCD, CXL
> +	 * SLD, CXL LD, CXL Fabric Manager Managed LD, CXL Root Port,
> +	 * CXL Downstream Switch Port and CXL Upstream Switch Port.
> +	 */
> +	if (!(agent_info[prot_err->agent_type].req_sbdf)) {
> +		pr_err(FW_WARN "Invalid agent type\n");
> +		return -EINVAL;
> +	}
> +
> +	rec->segment = prot_err->agent_addr.segment;
> +	rec->bus = prot_err->agent_addr.bus;
> +	rec->device = prot_err->agent_addr.device;
> +	rec->function = prot_err->agent_addr.function;
> +
> +	if (!(prot_err->valid_bits & PROT_ERR_VALID_ERROR_LOG)) {
> +		pr_err(FW_WARN "Invalid Protocol Error log\n");
> +		return -EINVAL;
> +	}
> +
> +	dvsec_start = (u8 *)(prot_err + 1);
> +	cap_start = dvsec_start + prot_err->dvsec_len;
> +	rec->cxl_ras = *(struct cxl_ras_capability_regs *)cap_start;
> +
> +	/*
> +	 * Set device serial number unconditionally.
> +	 *
> +	 * Print a warning message if it is not valid. The device serial
> +	 * number is required for CXL RCD, CXL SLD, CXL LD and CXL Fabric
> +	 * Manager Managed LD.
> +	 */
> +	if (!(prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER) ||
> +	    !(agent_info[prot_err->agent_type].req_sn))
> +		pr_warn(FW_WARN "No Device Serial number\n");
> +
> +	rec->lower_dw = prot_err->dev_serial_num.lower_dw;
> +	rec->upper_dw = prot_err->dev_serial_num.upper_dw;
> +
> +	rec->severity = cper_severity_cxl_aer(gdata->error_severity);
> +
> +	return 0;
> +}
> diff --git a/include/cxl/event.h b/include/cxl/event.h
> index 57b4630568f6..5b316150556a 100644
> --- a/include/cxl/event.h
> +++ b/include/cxl/event.h
> @@ -158,11 +158,37 @@ struct cxl_ras_capability_regs {
>  	u32 header_log[16];
>  };
>  
> +enum cxl_aer_err_type {
> +	CXL_AER_UNCORRECTABLE,
> +	CXL_AER_CORRECTABLE,
> +};
> +
> +struct cxl_cper_prot_err {
> +	struct cxl_ras_capability_regs cxl_ras;
> +
> +	/* Device ID */
> +	u8 function;
> +	u8 device;
> +	u8 bus;
> +	u16 segment;
> +
> +	/* Device Serial Number */
> +	u32 lower_dw;
> +	u32 upper_dw;
> +
> +	int severity;
> +};
> +
>  struct cxl_cper_work_data {
>  	enum cxl_event_type event_type;
>  	struct cxl_cper_event_rec rec;
> +	struct cxl_cper_prot_err p_rec;
>  };
>  
> +struct acpi_hest_generic_data;
> +int cxl_cper_handle_prot_err_info(struct acpi_hest_generic_data *gdata,
> +				  struct cxl_cper_prot_err *rec);
> +
>  #ifdef CONFIG_ACPI_APEI_GHES
>  int cxl_cper_register_work(struct work_struct *work);
>  int cxl_cper_unregister_work(struct work_struct *work);
> -- 
> 2.17.1
> 

-- 
Fan Ni