Re: [PATCH v5 2/7] libcxl: Add CXL protocol errors

[Alison Schofield <alison.schofield@intel.com>]

On Mon, Dec 15, 2025 at 03:36:25PM -0600, Ben Cheatham wrote:

snip

>  
> +const struct cxl_protocol_error cxl_protocol_errors[] = {
> +	CXL_PROTOCOL_ERROR(12, "cache-correctable"),
> +	CXL_PROTOCOL_ERROR(13, "cache-uncorrectable"),
> +	CXL_PROTOCOL_ERROR(14, "cache-fatal"),
> +	CXL_PROTOCOL_ERROR(15, "mem-correctable"),
> +	CXL_PROTOCOL_ERROR(16, "mem-uncorrectable"),
> +	CXL_PROTOCOL_ERROR(17, "mem-fatal")
> +};

Can the above 'num' fields be the same nums as sysfs emits?
ie. s/12/0x00001000

Then no BIT(X) needed in the look ups and reads as more obvious
mapping from sysfs, where it looks like this:

0x00001000	CXL.cache Protocol Correctable
0x00002000	CXL.cache Protocol Uncorrectable non-fatal
0x00004000	CXL.cache Protocol Uncorrectable fatal
0x00008000	CXL.mem Protocol Correctable
0x00010000	CXL.mem Protocol Uncorrectable non-fatal
0x00020000	CXL.mem Protocol Uncorrectable fatal

A spec reference for those would be useful too.

I notice that the cxl list emit of einj_types reverses the order that
is presented in sysfs. Would be nice to match.


snip
> +
> +CXL_EXPORT int cxl_dport_protocol_error_inject(struct cxl_dport *dport,
> +					       unsigned int error)
> +{
> +	struct cxl_ctx *ctx = dport->port->ctx;
> +	char buf[32] = { 0 };
> +	size_t path_len, len;
> +	char *path;
> +	int rc;
> +
> +	if (!ctx->debugfs)
> +		return -ENOENT;
> +
> +	path_len = strlen(ctx->debugfs) + 100;
> +	path = calloc(path_len, sizeof(char));
> +	if (!path)
> +		return -ENOMEM;
> +
> +	len = snprintf(path, path_len, "%s/cxl/%s/einj_inject", ctx->debugfs,
> +		      cxl_dport_get_devname(dport));
> +	if (len >= path_len) {
> +		err(ctx, "%s: buffer too small\n", cxl_dport_get_devname(dport));
> +		free(path);
> +		return -ENOMEM;
> +	}
> +
> +	rc = access(path, F_OK);
> +	if (rc) {
> +		err(ctx, "failed to access %s: %s\n", path, strerror(errno));
> +		free(path);
> +		return -errno;
> +	}
> +
> +	len = snprintf(buf, sizeof(buf), "0x%lx\n", BIT(error));
> +	if (len >= sizeof(buf)) {
> +		err(ctx, "%s: buffer too small\n", cxl_dport_get_devname(dport));
> +		free(path);
> +		return -ENOMEM;
> +	}
> +
> +	rc = sysfs_write_attr(ctx, path, buf);
> +	if (rc) {
> +		err(ctx, "failed to write %s: %s\n", path, strerror(-rc));
> +		free(path);
> +		return -errno;
> +	}

Coverity scan reports missing free(path) before return.


> +
> +	return 0;
> +}
> +