Re: [PATCH 4/7] cxl: Add inject-error command

Cheatham, Benjamin
2026-01-12T17:20:27Z

On 1/9/2026 3:53 PM, Dave Jiang wrote:
>
>
> On 1/9/26 9:07 AM, Ben Cheatham wrote:
>> Add the 'cxl-inject-error' command. This command will provide CXL
>> protocol error injection for CXL VH root ports and CXL RCH downstream
>> ports, as well as poison injection for CXL memory devices.
>>
>> Add util_cxl_dport_filter() to find downstream ports by device name.
>>
>> Signed-off-by: Ben Cheatham <Benjamin.Cheatham@amd.com>
>> ---

[snip]

>> +
>> +static int poison_action(struct cxl_ctx *ctx, const char *filter,
>> + const char *addr_str)
>> +{
>> + struct cxl_memdev *memdev;
>> + unsigned long long addr;
>> + int rc;
>> +
>> + memdev = find_cxl_memdev(ctx, filter);
>> + if (!memdev)
>> + return -ENODEV;
>> +
>> + if (!cxl_memdev_has_poison_injection(memdev)) {
>> + log_err(&iel, "%s does not support error injection\n",
>> + cxl_memdev_get_devname(memdev));
>> + return -EINVAL;
>> + }
>> +
>> + if (!addr_str) {
>> + log_err(&iel, "no address provided\n");
>> + return -EINVAL;
>> + }
>> +
>> + errno = 0;
>
> Why does errno needs to be set here?

Alison suggested it last revision. It's been a while so my memory is a bit hazy,
but I think strtoull() doesn't reset errno and checking it below could cause a problem
if it was set to ERANGE by a previous function.

>
>> + addr = strtoull(addr_str, NULL, 0);
>> + if (addr == ULLONG_MAX && errno == ERANGE) {
>> + log_err(&iel, "invalid address %s", addr_str);
>> + return -EINVAL;
>> + }
>> +
>> + rc = cxl_memdev_inject_poison(memdev, addr);
>> + if (rc)
>> + log_err(&iel, "failed to inject poison at %s:%s: %s\n",
>> + cxl_memdev_get_devname(memdev), addr_str, strerror(-rc));
>
> We don't error if poison fails to inject?

It does? The return code of cxl_memdev_inject_poison() is returned below, the only
thing that this if statement does is pick which message is emitted.

Thanks,
Ben

>
> DJ
>
>> + else
>> + log_info(&iel, "poison injected at %s:%s\n",
>> + cxl_memdev_get_devname(memdev), addr_str);
>> +
>> + return rc;
>> +}
>> +
>> +static int inject_action(int argc, const char **argv, struct cxl_ctx *ctx,
>> + const struct option *options, const char *usage)
>> +{
>> + struct cxl_protocol_error *perr;
>> + const char * const u[] = {
>> + usage,
>> + NULL
>> + };
>> + int rc = -EINVAL;
>> +
>> + log_init(&iel, "cxl inject-error", "CXL_INJECT_LOG");
>> + argc = parse_options(argc, argv, options, u, 0);
>> +
>> + if (debug) {
>> + cxl_set_log_priority(ctx, LOG_DEBUG);
>> + iel.log_priority = LOG_DEBUG;
>> + } else {
>> + iel.log_priority = LOG_INFO;
>> + }
>> +
>> + if (argc != 1 || inj_param.type == NULL) {
>> + usage_with_options(u, options);
>> + return rc;
>> + }
>> +
>> + if (strcmp(inj_param.type, "poison") == 0) {
>> + rc = poison_action(ctx, argv[0], inj_param.address);
>> + return rc;
>> + }
>> +
>> + perr = find_cxl_proto_err(ctx, inj_param.type);
>> + if (perr) {
>> + rc = inject_proto_err(ctx, argv[0], perr);
>> + if (rc)
>> + log_err(&iel, "Failed to inject error: %d\n", rc);
>> + }
>> +
>> + return rc;
>> +}
>> +
>> +int cmd_inject_error(int argc, const char **argv, struct cxl_ctx *ctx)
>> +{
>> + int rc = inject_action(argc, argv, ctx, inject_options,
>> + "inject-error <device> -t <type> [<options>]");
>> +
>> + return rc ? EXIT_FAILURE : EXIT_SUCCESS;
>> +}
>> diff --git a/cxl/meson.build b/cxl/meson.build
>> index b9924ae..92031b5 100644
>> --- a/cxl/meson.build
>> +++ b/cxl/meson.build
>> @@ -7,6 +7,7 @@ cxl_src = [
>> 'memdev.c',
>> 'json.c',
>> 'filter.c',
>> + 'inject-error.c',
>> '../daxctl/json.c',
>> '../daxctl/filter.c',
>> ]
>