Re: [PATCH v4] KVM: selftests: Add a test for gPAT handling in L2

[Yosry Ahmed]

> > > Anyone have a strong preference?  I like the goto approach (obviously), so that
> > > that all the gpat_test() invocations are prettily aligned.  But I can live with
> > > an if-statement as Yosry suggested.  I think the only option I don't like is
> > > moving the NPT tests to a separate helper (it's two lines of code, and testing
> > > the NPT case really is the focal point of the test).
> >
> > No strong preference, I obviously also like my suggestion :)
>
> Ok, third option, which I've pushed to kvm-x86/svm (but not kvm-x86/next, yet)
> in anticipation of overwhelming support:

Looks good, thank you!

>
> #define gpat_test(test_name, guest_code, npt_setting)                   \
> do {                                                                    \
>         npt_setting;                                                    \
>                                                                         \
>         if (npt_enabled && !kvm_cpu_has(X86_FEATURE_NPT)) {             \
>                 pr_info("Skipping: " test_name " (no NPT support)\n");  \
>                 break;                                                  \
>         }                                                               \
>                                                                         \
>         pr_info("Testing: " test_name "\n");                            \
>         run_test(guest_code, false, 1);                                 \
>                                                                         \
>         if (guest_code == l1_guest_code) {                              \
>                 pr_info("Testing: " test_name " Save/Restore\n");       \
>                 run_test(guest_code, true, 1);                          \
>                                                                         \
>                 pr_info("Testing: " test_name " Multiple VMRUNs\n");    \
>                 run_test(guest_code, false, 10);                        \
>         }                                                               \
> } while (0)
>
> int main(int argc, char *argv[])
> {
>         TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_SVM));
>         TEST_REQUIRE(kvm_has_cap(KVM_CAP_NESTED_STATE));
>         TEST_REQUIRE(kvm_check_cap(KVM_CAP_DISABLE_QUIRKS2) &
>                      KVM_X86_QUIRK_NESTED_SVM_SHARED_PAT);
>
>         gpat_test("Invalid gPAT", l1_guest_code_invalid_gpat, npt_enabled = true);
>         gpat_test("Nested NPT enabled", l1_guest_code, npt_enabled = true);
>         gpat_test("Nested NPT disabled", l1_guest_code, npt_enabled = false);
>         return 0;
> }
>
> Which (obviously) allows printing out which subtests are being skipped:
>
> # ./x86/svm_nested_pat_test
> Random seed: 0x6b8b4567
> Skipping: Invalid gPAT (no NPT support)
> Skipping: Nested NPT enabled (no NPT support)
> Testing: Nested NPT disabled
> Testing: Nested NPT disabled Save/Restore
> Testing: Nested NPT disabled Multiple VMRUNs
>