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

Dave Jiang
2026-01-09T21:53:53Z

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>
> ---
> cxl/builtin.h | 1 +
> cxl/cxl.c | 1 +
> cxl/filter.c | 26 +++++++
> cxl/filter.h | 2 +
> cxl/inject-error.c | 188 +++++++++++++++++++++++++++++++++++++++++++++
> cxl/meson.build | 1 +
> 6 files changed, 219 insertions(+)
> create mode 100644 cxl/inject-error.c
>
> diff --git a/cxl/builtin.h b/cxl/builtin.h
> index c483f30..e82fcb5 100644
> --- a/cxl/builtin.h
> +++ b/cxl/builtin.h
> @@ -25,6 +25,7 @@ int cmd_create_region(int argc, const char **argv, struct cxl_ctx *ctx);
> int cmd_enable_region(int argc, const char **argv, struct cxl_ctx *ctx);
> int cmd_disable_region(int argc, const char **argv, struct cxl_ctx *ctx);
> int cmd_destroy_region(int argc, const char **argv, struct cxl_ctx *ctx);
> +int cmd_inject_error(int argc, const char **argv, struct cxl_ctx *ctx);
> #ifdef ENABLE_LIBTRACEFS
> int cmd_monitor(int argc, const char **argv, struct cxl_ctx *ctx);
> #else
> diff --git a/cxl/cxl.c b/cxl/cxl.c
> index 1643667..a98bd6b 100644
> --- a/cxl/cxl.c
> +++ b/cxl/cxl.c
> @@ -80,6 +80,7 @@ static struct cmd_struct commands[] = {
> { "disable-region", .c_fn = cmd_disable_region },
> { "destroy-region", .c_fn = cmd_destroy_region },
> { "monitor", .c_fn = cmd_monitor },
> + { "inject-error", .c_fn = cmd_inject_error },
> };
>
> int main(int argc, const char **argv)
> diff --git a/cxl/filter.c b/cxl/filter.c
> index b135c04..8c7dc6e 100644
> --- a/cxl/filter.c
> +++ b/cxl/filter.c
> @@ -171,6 +171,32 @@ util_cxl_endpoint_filter_by_port(struct cxl_endpoint *endpoint,
> return NULL;
> }
>
> +struct cxl_dport *util_cxl_dport_filter(struct cxl_dport *dport,
> + const char *__ident)
> +{
> +
> + char *ident, *save;
> + const char *arg;
> +
> + if (!__ident)
> + return dport;
> +
> + ident = strdup(__ident);
> + if (!ident)
> + return NULL;
> +
> + for (arg = strtok_r(ident, which_sep(__ident), &save); arg;
> + arg = strtok_r(NULL, which_sep(__ident), &save)) {
> + if (strcmp(arg, cxl_dport_get_devname(dport)) == 0)
> + break;
> + }
> +
> + free(ident);
> + if (arg)
> + return dport;
> + return NULL;
> +}
> +
> static struct cxl_decoder *
> util_cxl_decoder_filter_by_port(struct cxl_decoder *decoder, const char *ident,
> enum cxl_port_filter_mode mode)
> diff --git a/cxl/filter.h b/cxl/filter.h
> index 956a46e..70463c4 100644
> --- a/cxl/filter.h
> +++ b/cxl/filter.h
> @@ -55,6 +55,8 @@ enum cxl_port_filter_mode {
>
> struct cxl_port *util_cxl_port_filter(struct cxl_port *port, const char *ident,
> enum cxl_port_filter_mode mode);
> +struct cxl_dport *util_cxl_dport_filter(struct cxl_dport *dport,
> + const char *__ident);
> struct cxl_bus *util_cxl_bus_filter(struct cxl_bus *bus, const char *__ident);
> struct cxl_endpoint *util_cxl_endpoint_filter(struct cxl_endpoint *endpoint,
> const char *__ident);
> diff --git a/cxl/inject-error.c b/cxl/inject-error.c
> new file mode 100644
> index 0000000..0ca2e6b
> --- /dev/null
> +++ b/cxl/inject-error.c
> @@ -0,0 +1,188 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (C) 2025 AMD. All rights reserved. */
> +#include <util/parse-options.h>
> +#include <cxl/libcxl.h>
> +#include <cxl/filter.h>
> +#include <util/log.h>
> +#include <stdlib.h>
> +#include <unistd.h>
> +#include <stdio.h>
> +#include <errno.h>
> +#include <limits.h>
> +
> +static bool debug;
> +
> +static struct inject_params {
> + const char *type;
> + const char *address;
> +} inj_param;
> +
> +static const struct option inject_options[] = {
> + OPT_STRING('t', "type", &inj_param.type, "Error type",
> + "Error type to inject into <device>"),
> + OPT_STRING('a', "address", &inj_param.address, "Address for poison injection",
> + "Device physical address for poison injection in hex or decimal"),
> +#ifdef ENABLE_DEBUG
> + OPT_BOOLEAN(0, "debug", &debug, "turn on debug output"),
> +#endif
> + OPT_END(),
> +};
> +
> +static struct log_ctx iel;
> +
> +static struct cxl_protocol_error *find_cxl_proto_err(struct cxl_ctx *ctx,
> + const char *type)
> +{
> + struct cxl_protocol_error *perror;
> +
> + cxl_protocol_error_foreach(ctx, perror) {
> + if (strcmp(type, cxl_protocol_error_get_str(perror)) == 0)
> + return perror;
> + }
> +
> + log_err(&iel, "Invalid CXL protocol error type: %s\n", type);
> + return NULL;
> +}
> +
> +static struct cxl_dport *find_cxl_dport(struct cxl_ctx *ctx, const char *devname)
> +{
> + struct cxl_dport *dport;
> + struct cxl_port *port;
> + struct cxl_bus *bus;
> +
> + cxl_bus_foreach(ctx, bus)
> + cxl_port_foreach_all(cxl_bus_get_port(bus), port)
> + cxl_dport_foreach(port, dport)
> + if (util_cxl_dport_filter(dport, devname))
> + return dport;
> +
> + log_err(&iel, "Downstream port \"%s\" not found\n", devname);
> + return NULL;
> +}
> +
> +static struct cxl_memdev *find_cxl_memdev(struct cxl_ctx *ctx,
> + const char *filter)
> +{
> + struct cxl_memdev *memdev;
> +
> + cxl_memdev_foreach(ctx, memdev) {
> + if (util_cxl_memdev_filter(memdev, filter, NULL))
> + return memdev;
> + }
> +
> + log_err(&iel, "Memdev \"%s\" not found\n", filter);
> + return NULL;
> +}
> +
> +static int inject_proto_err(struct cxl_ctx *ctx, const char *devname,
> + struct cxl_protocol_error *perror)
> +{
> + struct cxl_dport *dport;
> + int rc;
> +
> + if (!devname) {
> + log_err(&iel, "No downstream port specified for injection\n");
> + return -EINVAL;
> + }
> +
> + dport = find_cxl_dport(ctx, devname);
> + if (!dport)
> + return -ENODEV;
> +
> + rc = cxl_dport_protocol_error_inject(dport,
> + cxl_protocol_error_get_num(perror));
> + if (rc)
> + return rc;
> +
> + log_info(&iel, "injected %s protocol error.\n",
> + cxl_protocol_error_get_str(perror));
> + return 0;
> +}
> +
> +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?

> + 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?

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',
> ]