Re: [PATCH i-g-t] tools/intel_reg: add possibility to select device

[Jani Nikula <jani.nikula@intel.com>]

On Thu, 14 Mar 2024, Ashutosh Dixit <ashutosh.dixit@intel.com> wrote:
> From: Łukasz Łaguna <lukasz.laguna@intel.com>
>
> Device can be selected by slot or using filter. Example:
>
> intel_reg dump --slot "0000:01:00.0"
> intel_reg dump --filter "pci:vendor=8086"

Really, if you want to add device filtering, the sensible thing to do is
to mimic lspci -s or -d options instead of NIH'ing your own. Maybe add a
subset of the functionality first, but please don't deviate from the
format.

Other comments inline.

> Signed-off-by: Łukasz Łaguna <lukasz.laguna@intel.com>
> ---
>  tools/intel_reg.c | 128 +++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 126 insertions(+), 2 deletions(-)
>
> diff --git a/tools/intel_reg.c b/tools/intel_reg.c
> index 6c37e14d12..6b903f3f87 100644
> --- a/tools/intel_reg.c
> +++ b/tools/intel_reg.c
> @@ -39,6 +39,7 @@
>  #include "intel_chipset.h"
>  
>  #include "intel_reg_spec.h"
> +#include "igt_device_scan.h"
>  
>  
>  #ifdef HAVE_SYS_IO_H
> @@ -86,6 +87,13 @@ struct config {
>  	int verbosity;
>  };
>  
> +struct pci_slot {

The name has clash potential with pci libs.

> +	int domain;
> +	int bus;
> +	int dev;
> +	int func;
> +};
> +
>  /* port desc must have been set */
>  static int set_reg_by_addr(struct config *config, struct reg *reg,
>  			   uint32_t addr)
> @@ -958,6 +966,12 @@ static int intel_reg_list(struct config *config, int argc, char *argv[])
>  	return EXIT_SUCCESS;
>  }
>  
> +static int intel_reg_list_filters(struct config *config, int argc, char *argv[])
> +{
> +	igt_device_print_filter_types();
> +	return EXIT_SUCCESS;
> +}
> +
>  static int intel_reg_help(struct config *config, int argc, char *argv[]);
>  
>  struct command {
> @@ -1001,6 +1015,11 @@ static const struct command commands[] = {
>  		.function = intel_reg_list,
>  		.description = "list all known register names",
>  	},
> +	{
> +		.name = "list_filters",

Please do not use underscore in subcommands. list-filters.

When you update the command-line interface, a man page update is
required as well: man/intel_reg.rst.

> +		.function = intel_reg_list_filters,
> +		.description = "list registered device filters types",
> +	},
>  	{
>  		.name = "help",
>  		.function = intel_reg_help,
> @@ -1041,6 +1060,8 @@ static int intel_reg_help(struct config *config, int argc, char *argv[])
>  	printf(" --mmio=FILE    Use an MMIO snapshot\n");
>  	printf(" --devid=DEVID  Specify PCI device ID for --mmio=FILE\n");
>  	printf(" --all          Decode registers for all known platforms\n");
> +	printf(" --filter       Decode registers for platform described by filter\n");
> +	printf(" --slot         Decode registers for platform described by slot\n");
>  	printf(" --binary       Binary dump registers\n");
>  	printf(" --verbose      Increase verbosity\n");
>  	printf(" --quiet        Reduce verbosity\n");
> @@ -1147,6 +1168,52 @@ builtin:
>  	return config->regcount;
>  }
>  
> +static void parse_pci_slot_name(struct pci_slot *pci_slot, const char *pci_slot_name)
> +{
> +	igt_assert_eq(sscanf(pci_slot_name, "%x:%x:%x.%x",
> +		&pci_slot->domain, &pci_slot->bus, &pci_slot->dev, &pci_slot->func), 4);

This is a tool, not a test. Please do not use igt_assert or anything
like that. Handle the errors and fprintf a message to stderr.

> +}
> +
> +static struct pci_device *find_intel_graphics_card(void)
> +{
> +	struct pci_device *pci_dev;
> +	struct pci_device_iterator *iter;
> +	struct pci_id_match match;
> +
> +	match.vendor_id = 0x8086; /* Intel */
> +	match.device_id = PCI_MATCH_ANY;
> +	match.subvendor_id = PCI_MATCH_ANY;
> +	match.subdevice_id = PCI_MATCH_ANY;
> +
> +	match.device_class = 0x3 << 16;
> +	match.device_class_mask = 0xff << 16;
> +
> +	match.match_data = 0;
> +
> +	iter = pci_id_match_iterator_create(&match);
> +	pci_dev = pci_device_next(iter);
> +	pci_iterator_destroy(iter);
> +
> +	return pci_dev;
> +}
> +
> +static bool is_graphics_card_valid(struct pci_device *pci_dev)
> +{
> +	if (!pci_dev) {
> +		fprintf(stderr, "Graphics card not found\n");
> +		return false;
> +	}
> +	if (pci_device_probe(pci_dev) != 0) {
> +		fprintf(stderr, "Couldn't probe graphics card\n");
> +		return false;
> +	}
> +	if (pci_dev->vendor_id != 0x8086) {
> +		fprintf(stderr, "Graphics card is non-intel\n");
> +		return false;
> +	}
> +	return true;
> +}
> +
>  enum opt {
>  	OPT_UNKNOWN = '?',
>  	OPT_END = -1,
> @@ -1155,6 +1222,8 @@ enum opt {
>  	OPT_COUNT,
>  	OPT_POST,
>  	OPT_ALL,
> +	OPT_FILTER,
> +	OPT_SLOT,
>  	OPT_BINARY,
>  	OPT_SPEC,
>  	OPT_VERBOSE,
> @@ -1164,8 +1233,12 @@ enum opt {
>  
>  int main(int argc, char *argv[])
>  {
> -	int ret, i, index;
> +	int ret, i, index, len;
>  	char *endp;
> +	char *opt_filter = NULL;
> +	struct pci_slot bdf;
> +	struct pci_device *pci_dev = NULL;
> +	struct igt_device_card card;
>  	enum opt opt;
>  	const struct command *command = NULL;
>  	struct config config = {
> @@ -1189,6 +1262,8 @@ int main(int argc, char *argv[])
>  		{ "post",	no_argument,		NULL,	OPT_POST },
>  		/* options specific to read, dump and decode */
>  		{ "all",	no_argument,		NULL,	OPT_ALL },
> +		{ "filter",	required_argument,	NULL,	OPT_FILTER },
> +		{ "slot",	required_argument,	NULL,	OPT_SLOT },
>  		{ "binary",	no_argument,		NULL,	OPT_BINARY },
>  		{ 0 }
>  	};
> @@ -1233,6 +1308,24 @@ int main(int argc, char *argv[])
>  		case OPT_ALL:
>  			config.all_platforms = true;
>  			break;
> +		case OPT_FILTER:
> +			opt_filter = strdup(optarg);
> +			if (!opt_filter) {
> +				fprintf(stderr, "strdup: %s\n",
> +					strerror(errno));
> +				return EXIT_FAILURE;
> +			}
> +			break;
> +		case OPT_SLOT:
> +			len = strlen("pci:slot=") + strlen(optarg) + 1;
> +			opt_filter = malloc(len);
> +			snprintf(opt_filter, len, "%s%s", "pci:slot=", optarg);
> +			if (!opt_filter) {

snprintf() would've crashed by now if !opt_filter.

But maybe you're looking for asprintf() instead.

> +				fprintf(stderr, "opt_filter: %s\n",
> +					strerror(errno));
> +				return EXIT_FAILURE;
> +			}
> +			break;

Adding both --filter and --slot options leaks opt_filter. It's benign
for a small tool like this, but still wrong.

>  		case OPT_BINARY:
>  			config.binary = true;
>  			break;
> @@ -1258,6 +1351,9 @@ int main(int argc, char *argv[])
>  	if (help || (argc > 0 && strcmp(argv[0], "help") == 0))
>  		return intel_reg_help(&config, argc, argv);
>  
> +	if (argc > 0 && strcmp(argv[0], "list_filters") == 0)
> +		return intel_reg_list_filters(&config, argc, argv);
> +
>  	if (argc == 0) {
>  		fprintf(stderr, "Command missing. Try intel_reg help.\n");
>  		return EXIT_FAILURE;
> @@ -1274,7 +1370,32 @@ int main(int argc, char *argv[])
>  			fprintf(stderr, "--devid without --mmio\n");
>  			return EXIT_FAILURE;
>  		}
> -		config.pci_dev = intel_get_pci_device();
> +
> +		if (pci_system_init() != 0) {
> +			fprintf(stderr, "Couldn't initialize PCI system\n");
> +			return EXIT_FAILURE;
> +		}
> +
> +		igt_devices_scan(false);
> +
> +		if (opt_filter) {
> +			if (!igt_device_card_match(opt_filter, &card)) {
> +				fprintf(stderr, "Requested device %s not found!\n", opt_filter);
> +				ret = EXIT_FAILURE;
> +				goto exit;
> +			}
> +			parse_pci_slot_name(&bdf, card.pci_slot_name);
> +			pci_dev = pci_device_find_by_slot(bdf.domain, bdf.bus, bdf.dev, bdf.func);
> +		} else {
> +			pci_dev = find_intel_graphics_card();
> +		}
> +
> +		if (!is_graphics_card_valid(pci_dev)) {
> +			ret = EXIT_FAILURE;
> +			goto exit;
> +		}
> +

All of the above should be abstracted to a function instead of crammed
into main().

> +		config.pci_dev = pci_dev;
>  		config.devid = config.pci_dev->device_id;
>  	}
>  
> @@ -1301,5 +1422,8 @@ int main(int argc, char *argv[])
>  	if (config.fd >= 0)
>  		close(config.fd);
>  
> +exit:
> +	igt_devices_free();
> +	free(opt_filter);
>  	return ret;
>  }

-- 
Jani Nikula, Intel