On Tue, 7 Jul 2020 12:42:05 +0200
Thomas Huth <thuth@xxxxxxxxxx> wrote:
> When running the kvm-unit-tests with TCG on s390x, the cpumodel test
> always reports the error about the missing DFP (decimal floating point)
> facility. This is kind of expected, since DFP is not required for
> running Linux and thus nobody is really interested in implementing
> this facility in TCG. Thus let's mark this as an expected error instead,
> so that we can run the kvm-unit-tests also with TCG without getting
> test failures that we do not care about.
>
> Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
> ---
> v2:
> - Rewrote the logic, introduced expected_tcg_fail flag
> - Use manufacturer string instead of VM name to detect TCG
>
> s390x/cpumodel.c | 49 ++++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 43 insertions(+), 6 deletions(-)
(...)
> +static bool is_tcg(void)
> +{
> + const char qemu_ebcdic[] = { 0xd8, 0xc5, 0xd4, 0xe4 };
> + bool ret = false;
> + uint8_t *buf;
> +
> + buf = alloc_page();
> + if (!buf)
> + return false;
> +
> + if (stsi(buf, 1, 1, 1)) {
> + goto out;
> + }
This does an alloc_page() and a stsi() every time you call it...
> +
> + /*
> + * If the manufacturer string is "QEMU" in EBCDIC, then we are on TCG
> + * (otherwise the string is "IBM" in EBCDIC)
> + */
> + if (!memcmp(&buf[32], qemu_ebcdic, sizeof(qemu_ebcdic)))
> + ret = true;
> +out:
> + free_page(buf);
> + return ret;
> +}
> +
> +
> int main(void)
> {
> int i;
> @@ -46,11 +81,13 @@ int main(void)
>
> report_prefix_push("dependency");
...so maybe cache the value for is_tcg() here instead of checking
multiple times in the loop?
(Or cache the value in is_tcg().)
> for (i = 0; i < ARRAY_SIZE(dep); i++) {
> - if (test_facility(dep[i][0])) {
> - report(test_facility(dep[i][1]), "%d implies %d",
> - dep[i][0], dep[i][1]);
> + if (test_facility(dep[i].facility)) {
> + report_xfail(dep[i].expected_tcg_fail && is_tcg(),
> + test_facility(dep[i].implied),
> + "%d implies %d",
> + dep[i].facility, dep[i].implied);
> } else {
> - report_skip("facility %d not present", dep[i][0]);
> + report_skip("facility %d not present", dep[i].facility);
> }
> }
> report_prefix_pop();
