Re: [PATCH v12 2/3] selftests: tdx: Test TDX attestation GetReport support

Sathyanarayanan Kuppuswamy
2022-09-08T23:45:18Z

On 9/8/22 7:16 AM, Wander Lairson Costa wrote:
>> +#ifdef DEBUG
>> +static void print_array_hex(const char *title, const char *prefix_str,
>> + const void *buf, int len)
>> +{
>> + const __u8 *ptr = buf;
>> + int i, rowsize = HEX_DUMP_SIZE;
>> +
>> + if (!len || !buf)
>> + return;
>> +
>> + printf("\t\t%s", title);
>> +
>> + for (i = 0; i < len; i++) {
>> + if (!(i % rowsize))
>> + printf("\n%s%.8x:", prefix_str, i);
>> + printf(" %.2x", ptr[i]);
>> + }
>> +
>> + printf("\n");
>> +}
>> +#endif
>> +
>> +TEST(verify_report)
>> +{
>> + __u8 reportdata[TDX_REPORTDATA_LEN];
>> + struct tdreport tdreport;
>> + struct tdx_report_req req;
>> + int devfd, i;
>> +
>> + devfd = open(TDX_GUEST_DEVNAME, O_RDWR | O_SYNC);
>> +
>> + ASSERT_LT(0, devfd);
>> +
>> + /* Generate sample report data */
>> + for (i = 0; i < TDX_REPORTDATA_LEN; i++)
>> + reportdata[i] = i;
>> +
>> + /* Initialize IOCTL request */
>> + req.subtype = 0;
>> + req.reportdata = (__u64)reportdata;
>> + req.rpd_len = TDX_REPORTDATA_LEN;
>> + req.tdreport = (__u64)&tdreport;
>> + req.tdr_len = sizeof(tdreport);
>> +
>> + /* Get TDREPORT */
>> + ASSERT_EQ(0, ioctl(devfd, TDX_CMD_GET_REPORT, &req));
>> +
>> +#ifdef DEBUG
>> + print_array_hex("\n\t\tTDX report data\n", "",
>> + reportdata, sizeof(reportdata));
>> +
>> + print_array_hex("\n\t\tTDX tdreport data\n", "",
>> + &tdreport, sizeof(tdreport));
>> +#endif
> You can unconditionally define print_array_hex, and
> use `if (DEBUG)` instead of #ifdef `DEBUG here`. The compiler
> will get rid of the unused code when DEBUG is not defined
> as expected, but you get the parser to validate it
> independent of the definition of DEBUG.

Currently, DEBUG is a macro, so we cannot use if (DEBUG) directly.
You are suggesting to change DEBUG to a variable? Any reason to
make this change? I think both changes are functionally similar.
So I am wondering why to make this change?

>

--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer