On Tue, 7 Jul 2020 07:56:19 +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.
Checking for tcg seems reasonable.
>
> Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
> ---
> s390x/cpumodel.c | 51 ++++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 45 insertions(+), 6 deletions(-)
>
> diff --git a/s390x/cpumodel.c b/s390x/cpumodel.c
> index 5d232c6..4310b92 100644
> --- a/s390x/cpumodel.c
> +++ b/s390x/cpumodel.c
> @@ -11,6 +11,7 @@
> */
>
> #include <asm/facility.h>
> +#include <alloc_page.h>
>
> static int dep[][2] = {
> /* from SA22-7832-11 4-98 facility indications */
> @@ -38,6 +39,49 @@ static int dep[][2] = {
> { 155, 77 },
> };
>
> +/*
> + * A hack to detect TCG (instead of KVM): QEMU uses "TCGguest" as guest
> + * name by default when we are running with TCG (otherwise it's "KVMguest")
The guest name can be overwritten; I think it would be better to check
for something hardcoded.
Maybe the manufacturer name in SYSIB 1.1.1? When running under tcg,
it's always 'QEMU' (it's 'IBM' when running under KVM).
> + */
> +static bool is_tcg(void)
> +{
> + bool ret = false;
> + uint8_t *buf;
> +
> + buf = alloc_page();
> + if (!buf)
> + return false;
> +
> + if (stsi(buf, 3, 2, 2)) {
> + goto out;
> + }
> +
> + /* Does the name start with "TCG" in EBCDIC? */
> + if (buf[2048] == 0x54 && buf[2049] == 0x43 && buf[2050] == 0x47)
> + ret = true;
> +
> +out:
> + free_page(buf);
> + return ret;
> +}
> +
> +static void check_dependency(int dep1, int dep2)
<bikeshed>
Can we find more speaking parameter names? facility/implied?
</bikeshed>
> +{
> + if (test_facility(dep1)) {
> + if (dep1 == 37) {
> + /* TCG does not have DFP and is unlikely to
> + * get it implemented soon. */
> + report_xfail(is_tcg(), test_facility(dep2),
> + "%d implies %d", dep1, dep2);
> + } else {
> + report(test_facility(dep2), "%d implies %d",
> + dep1, dep2);
> + }
> + } else {
> + report_skip("facility %d not present", dep1);
> + }
> +}
> +
> int main(void)
> {
> int i;
> @@ -46,12 +90,7 @@ int main(void)
>
> report_prefix_push("dependency");
> 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]);
> - } else {
> - report_skip("facility %d not present", dep[i][0]);
> - }
> + check_dependency(dep[i][0], dep[i][1]);
> }
> report_prefix_pop();
>
