In preparation for adding more test cases, make the test easier to extend. Create a generic helper that sets an arbitrary bit in CR0, optionally using FEP. The helper also stores the value to be written in test->scratch, making it possible to double check if the write was actually executed or not. Use report_svm_guest() instead of report_fail() + exit(). Make test_sel_cr0_write_intercept() use the generic helper, and add another test case that sets FEP to exercise the interception path in the emulator. Finally, in check_sel_cr0_intercept() also check that the write was not executed by comparing CR0 value in the VMCB12 with the value-to-be-written stored in test->scratch. Signed-off-by: Yosry Ahmed --- x86/svm_tests.c | 38 +++++++++++++++++++++++++------------- 1 file changed, 25 insertions(+), 13 deletions(-) diff --git a/x86/svm_tests.c b/x86/svm_tests.c index 1e7556a37adec..7e292a9a7b4ec 100644 --- a/x86/svm_tests.c +++ b/x86/svm_tests.c @@ -133,27 +133,36 @@ static void prepare_sel_cr0_intercept(struct svm_test *test) vmcb->control.intercept |= (1ULL << INTERCEPT_SELECTIVE_CR0); } -static void test_sel_cr0_write_intercept(struct svm_test *test) +static void __test_cr0_write_bit(struct svm_test *test, unsigned long bit, + bool intercept, bool fep) { unsigned long cr0; - /* read cr0, set CD, and write back */ - cr0 = read_cr0(); - cr0 |= X86_CR0_CD; - write_cr0(cr0); + cr0 = read_cr0(); + cr0 |= bit; + test->scratch = cr0; - /* - * If we are here the test failed, not sure what to do now because we - * are not in guest-mode anymore so we can't trigger an intercept. - * Trigger a tripple-fault for now. - */ - report_fail("sel_cr0 test. Can not recover from this - exiting"); - exit(report_summary()); + asm_conditional_fep_safe(fep, "mov %0,%%cr0", "r"(cr0)); + + /* This code should be unreachable when an intercept is expected */ + report_svm_guest(!intercept, test, "Expected intercept on CR0 write"); +} + +/* MOV-to-CR0 updating CR0.CD is intercepted by the selective intercept */ +static void test_sel_cr0_write_intercept(struct svm_test *test) +{ + __test_cr0_write_bit(test, X86_CR0_CD, true, false); +} + +static void test_sel_cr0_write_intercept_emul(struct svm_test *test) +{ + __test_cr0_write_bit(test, X86_CR0_CD, true, true); } static bool check_sel_cr0_intercept(struct svm_test *test) { - return vmcb->control.exit_code == SVM_EXIT_CR0_SEL_WRITE; + return vmcb->control.exit_code == SVM_EXIT_CR0_SEL_WRITE && + vmcb->save.cr0 != test->scratch; } static void prepare_cr3_intercept(struct svm_test *test) @@ -3461,6 +3470,9 @@ struct svm_test svm_tests[] = { { "sel cr0 write intercept", default_supported, prepare_sel_cr0_intercept, default_prepare_gif_clear, test_sel_cr0_write_intercept, default_finished, check_sel_cr0_intercept}, + { "sel cr0 write intercept emulate", fep_supported, + prepare_sel_cr0_intercept, default_prepare_gif_clear, + test_sel_cr0_write_intercept_emul, default_finished, check_sel_cr0_intercept}, { "cr3 read intercept", default_supported, prepare_cr3_intercept, default_prepare_gif_clear, test_cr3_intercept, default_finished, check_cr3_intercept }, -- 2.51.2.1041.gc1ab5b90ca-goog