[PATCH 6/7] KVM: selftests: Verify guest debug DR7.GD checking during instruction emulation

[Hou Wenlong]

Similar to the global disable test case in x86's debug_regs test, use
'KVM_FEP' to trigger instruction emulation in order to verify the guest
debug DR7.GD checking during instruction emulation.

Signed-off-by: Hou Wenlong <houwenlong....@antgroup.com>
---
 tools/testing/selftests/kvm/x86/debug_regs.c | 25 +++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/x86/debug_regs.c 
b/tools/testing/selftests/kvm/x86/debug_regs.c
index 2d814c1d1dc4..ba80b77c2869 100644
--- a/tools/testing/selftests/kvm/x86/debug_regs.c
+++ b/tools/testing/selftests/kvm/x86/debug_regs.c
@@ -19,6 +19,7 @@
 uint32_t guest_value;
 
 extern unsigned char sw_bp, hw_bp, write_data, ss_start, bd_start;
+extern unsigned char fep_bd_start;
 
 static void guest_code(void)
 {
@@ -64,6 +65,12 @@ static void guest_code(void)
 
        /* DR6.BD test */
        asm volatile("bd_start: mov %%dr0, %%rax" : : : "rax");
+
+       if (is_forced_emulation_enabled) {
+               /* DR6.BD test for emulation */
+               asm volatile(KVM_FEP "fep_bd_start: mov %%dr0, %%rax" : : : 
"rax");
+       }
+
        GUEST_DONE();
 }
 
@@ -185,7 +192,7 @@ int main(void)
                            target_dr6);
        }
 
-       /* Finally test global disable */
+       /* test global disable */
        memset(&debug, 0, sizeof(debug));
        debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;
        debug.arch.debugreg[7] = 0x400 | DR7_GD;
@@ -202,6 +209,22 @@ int main(void)
                            run->debug.arch.pc, target_rip, run->debug.arch.dr6,
                            target_dr6);
 
+       /* test global disable in emulation */
+       if (is_forced_emulation_enabled) {
+               /* Skip the 3-bytes "mov dr0" */
+               vcpu_skip_insn(vcpu, 3);
+               vcpu_run(vcpu);
+               TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
+                           run->debug.arch.exception == DB_VECTOR &&
+                           run->debug.arch.pc == CAST_TO_RIP(fep_bd_start) &&
+                           run->debug.arch.dr6 == target_dr6,
+                           "DR7.GD: exit %d exception %d rip 0x%llx "
+                           "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",
+                           run->exit_reason, run->debug.arch.exception,
+                           run->debug.arch.pc, target_rip, run->debug.arch.dr6,
+                           target_dr6);
+       }
+
        /* Disable all debug controls, run to the end */
        memset(&debug, 0, sizeof(debug));
        vcpu_guest_debug_set(vcpu, &debug);
-- 
2.31.1