[PATCH 4/4][kvm-unit-test nVMX]: Test "load IA32_PERF_GLOBAL_CONTROL" VM-entry control on vmentry of nested guests

[Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>]

 ..to verify KVM performs the appropriate consistency checks for loading
   IA32_PERF_GLOBAL_CONTROL as part of running a nested guest.

According to section "Checking and Loading Guest State" in Intel SDM
vol 3C, the following check is performed on vmentry:

   If the "load IA32_PERF_GLOBAL_CTRL" VM-exit control is 1, bits reserved
   in the IA32_PERF_GLOBAL_CTRL MSR must be 0 in the field for that register.

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
Reviewed-by: Karl Heubaum <karl.heubaum@xxxxxxxxxx>
---
 x86/vmx_tests.c | 82 ++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 71 insertions(+), 11 deletions(-)

diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index a339bb3..65772ce 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -5031,29 +5031,69 @@ static void test_perf_global_ctl(u32 field, const char * field_name,
 	u64 perf_global_saved = vmcs_read(field);
 	u64 i, val;
 
+	if (field == GUEST_PERF_GLOBAL_CTRL) {
+		vmx_set_test_stage(1);
+		test_set_guest(guest_state_test_main);
+	}
+
 	vmcs_write(ctrl_field, ctrl_saved & ~ctrl_bit);
 	for (i = 0; i < 64; i++) {
 		val = 1ull << i;
 		vmcs_write(field, val);
-		report_prefix_pushf("\"load IA32_PERF_GLOBAL_CTRL\" "
-		    "VM-exit control is off, HOST_PERF_GLOBAL_CTRL %lx", val);
-		test_vmx_vmlaunch(0, false);
-		report_prefix_pop();
+		if (field == HOST_PERF_GLOBAL_CTRL) {
+			report_prefix_pushf("\"load IA32_PERF_GLOBAL_CTRL\" "
+					    "VM-exit control is off, "
+					    "HOST_PERF_GLOBAL_CTRL %lx", val);
+			test_vmx_vmlaunch(0, false);
+			report_prefix_pop();
+		} else {        // GUEST_PERF_GLOBAL_CTRL
+			enter_guest();
+			report_guest_state_test("ENT_LOAD_PERF disabled",
+						 VMX_VMCALL, val,
+						"GUEST_PERF_GLOBAL_CTRL");
+		}
 	}
 
 	vmcs_write(ctrl_field, ctrl_saved | ctrl_bit);
 	for (i = 0; i < 64; i++) {
 		val = 1ull << i;
 		vmcs_write(field, val);
-		report_prefix_pushf("\"load IA32_PERF_GLOBAL_CTRL\" "
-		    "VM-exit control is on, HOST_PERF_GLOBAL_CTRL %lx", val);
-		if (PERF_GLOBAL_CTRL_VALID_BITS & (1ull << i)) {
-			test_vmx_vmlaunch(0, false);
-		} else {
-			test_vmx_vmlaunch(VMXERR_ENTRY_INVALID_HOST_STATE_FIELD,
-					  false);
+		if (field == HOST_PERF_GLOBAL_CTRL) {
+			report_prefix_pushf("\"load IA32_PERF_GLOBAL_CTRL\" "
+			"VM-exit control is on, HOST_PERF_GLOBAL_CTRL %lx",
+			val);
+			if (PERF_GLOBAL_CTRL_VALID_BITS & (1ull << i)) {
+				test_vmx_vmlaunch(0, false);
+			} else {
+				test_vmx_vmlaunch(
+					VMXERR_ENTRY_INVALID_HOST_STATE_FIELD,
+					false);
 		}
 		report_prefix_pop();
+		} else {        // GUEST_PERF_GLOBAL_CTRL
+			enter_guest();
+			if (PERF_GLOBAL_CTRL_VALID_BITS & (1ull << i)) {
+				report_guest_state_test("ENT_LOAD_PERF enabled",
+						VMX_FAIL_STATE |
+						VMX_ENTRY_FAILURE,
+						val,
+						"GUEST_PERF_GLOBAL_CTRL");
+			} else {
+				report_guest_state_test("ENT_LOAD_PERF enabled",
+						VMX_VMCALL,
+						val,
+						"GUEST_PERF_GLOBAL_CTRL");
+			}
+		}
+	}
+
+	if (field == GUEST_PERF_GLOBAL_CTRL) {
+		/*
+		 * Let the guest finish execution
+		 */
+		vmx_set_test_stage(2);
+		vmcs_write(field, perf_global_saved);
+		enter_guest();
 	}
 
 	vmcs_write(ctrl_field, ctrl_saved);
@@ -5079,6 +5119,25 @@ static void test_host_perf_global_ctl(void)
 			     EXI_CONTROLS, EXI_LOAD_PERF);
 }
 
+/*
+ * If the "load IA32_PERF_GLOBAL_CTRL" VM-entry control is 1, bits reserved
+ * in the IA32_PERF_GLOBAL_CTRL MSR must be 0 in the field for that
+ * register.
+ *
+ *  [Intel SDM]
+ */
+static void test_guest_perf_global_ctl(void)
+{
+	if (!(ctrl_exit_rev.clr & ENT_LOAD_PERF)) {
+		printf("\"load IA32_PERF_GLOBAL_CTRL\" VM-entry control not "
+			"supported\n");
+		return;
+	}
+
+	test_perf_global_ctl(GUEST_PERF_GLOBAL_CTRL, "GUEST_PERF_GLOBAL_CTRL",
+			     ENT_CONTROLS, ENT_LOAD_PERF);
+}
+
 /*
  * PAT values higher than 8 are uninteresting since they're likely lumped
  * in with "8". We only test values above 8 one bit at a time,
@@ -5243,6 +5302,7 @@ static void test_load_guest_pat(void)
  */
 static void vmx_guest_state_area_test(void)
 {
+	test_guest_perf_global_ctl();
 	test_load_guest_pat();
 }
 
-- 
2.20.1