According to section "VMRUN and TF/RF Bits in EFLAGS." in APM vol 2,
"When VMRUN loads a guest value of 1 in EFLAGS.TF, that value does not
cause a trace trap between the VMRUN and the first guest instruction,
but rather after completion of the first guest instruction."
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
---
x86/svm_tests.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)
diff --git a/x86/svm_tests.c b/x86/svm_tests.c
index a56a197..2d06d9e 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -2491,6 +2491,66 @@ static void test_vmrun_canonicalization(void)
TEST_CANONICAL(vmcb->save.tr.base, "TR");
}
+/*
+ * When VMRUN loads a guest value of 1 in EFLAGS.TF, that value does not
+ * cause a trace trap between the VMRUN and the first guest instruction, but
+ * rather after completion of the first guest instruction.
+ *
+ * [APM vol 2]
+ */
+u64 guest_rflags_test_trap_rip;
+
+static void guest_rflags_test_db_handler(struct ex_regs *r)
+{
+ guest_rflags_test_trap_rip = r->rip;
+ r->rflags &= ~X86_EFLAGS_TF;
+}
+
+extern void guest_rflags_test_guest(struct svm_test *test);
+extern u64 *insn2;
+extern u64 *guest_end;
+
+asm("guest_rflags_test_guest:\n\t"
+ "push %rbp\n\t"
+ ".global insn2\n\t"
+ "insn2:\n\t"
+ "mov %rsp,%rbp\n\t"
+ "vmmcall\n\t"
+ "vmmcall\n\t"
+ ".global guest_end\n\t"
+ "guest_end:\n\t"
+ "vmmcall\n\t"
+ "pop %rbp\n\t"
+ "ret");
+
+static void test_guest_rflags(void)
+{
+ handle_exception(DB_VECTOR, guest_rflags_test_db_handler);
+
+ /*
+ * Trap expected after completion of first guest instruction
+ */
+ vmcb->save.rflags |= X86_EFLAGS_TF;
+ report (svm_vmrun_custom((u64)guest_rflags_test_guest) == SVM_EXIT_VMMCALL &&
+ guest_rflags_test_trap_rip == (u64)&insn2,
+ "Test EFLAGS.TF on VMRUN: trap expected after completion of first guest instruction");
+ /*
+ * No trap expected
+ */
+ guest_rflags_test_trap_rip = 0;
+ vmcb->save.rip += 3;
+ vmcb->save.rflags |= X86_EFLAGS_TF;
+ report (svm_vmrun_custom(vmcb->save.rip) == SVM_EXIT_VMMCALL &&
+ guest_rflags_test_trap_rip == 0, "Test EFLAGS.TF on VMRUN: trap not expected");
+
+ /*
+ * Let guest finish execution
+ */
+ vmcb->save.rip += 3;
+ report (svm_vmrun_custom(vmcb->save.rip) == SVM_EXIT_VMMCALL &&
+ vmcb->save.rip == (u64)&guest_end, "Test EFLAGS.TF on VMRUN: guest execution completion");
+}
+
static void svm_guest_state_test(void)
{
test_set_guest(basic_guest_main);
@@ -2501,6 +2561,7 @@ static void svm_guest_state_test(void)
test_dr();
test_msrpm_iopm_bitmap_addrs();
test_vmrun_canonicalization();
+ test_guest_rflags();
}
static void __svm_npt_rsvd_bits_test(u64 *pxe, u64 rsvd_bits, u64 efer,
--
2.27.0
