[kvm-unit-tests PATCH v3 5/9] x86: nSVM: Add an exception test framework and tests

[Sean Christopherson <seanjc@xxxxxxxxxx>]

From: Manali Shukla <manali.shukla@xxxxxxx>

Copy nVMX's test that verifies an exception occurring in L2 is
forwarded to the right place (L1 or L2).

The test verifies two conditions for each exception.
1) Exception generated in L2, is handled by L2 when L2 exception handler
   is registered.
2) Exception generated in L2, is handled by L1 when intercept exception
   bit map is set in L1.

Note, v2 SVM tests have no parameters, but the SVM framework doesn't
differentiate between v1 and v2 when setting the guest code.  Fudge
around this shortcoming by casting to test_guest_func when invoking
test_set_guest().

Signed-off-by: Manali Shukla <manali.shukla@xxxxxxx>
[sean: use common helpers to generate exception, call out this copies nVMX]
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 x86/svm_tests.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/x86/svm_tests.c b/x86/svm_tests.c
index e2ec954..805b2e0 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -10,6 +10,7 @@
 #include "isr.h"
 #include "apic.h"
 #include "delay.h"
+#include "x86/usermode.h"
 
 #define SVM_EXIT_MAX_DR_INTERCEPT 0x3f
 
@@ -3289,6 +3290,81 @@ static void svm_intr_intercept_mix_smi(void)
 	svm_intr_intercept_mix_run_guest(NULL, SVM_EXIT_SMI);
 }
 
+static void svm_l2_ac_test(void)
+{
+	bool hit_ac = false;
+
+	write_cr0(read_cr0() | X86_CR0_AM);
+	write_rflags(read_rflags() | X86_EFLAGS_AC);
+
+	run_in_user(generate_usermode_ac, AC_VECTOR, 0, 0, 0, 0, &hit_ac);
+	report(hit_ac, "Usermode #AC handled in L2");
+	vmmcall();
+}
+
+struct svm_exception_test {
+	u8 vector;
+	void (*guest_code)(void);
+};
+
+struct svm_exception_test svm_exception_tests[] = {
+	{ GP_VECTOR, generate_non_canonical_gp },
+	{ UD_VECTOR, generate_ud },
+	{ DE_VECTOR, generate_de },
+	{ DB_VECTOR, generate_single_step_db },
+	{ AC_VECTOR, svm_l2_ac_test },
+};
+
+static u8 svm_exception_test_vector;
+
+static void svm_exception_handler(struct ex_regs *regs)
+{
+	report(regs->vector == svm_exception_test_vector,
+		"Handling %s in L2's exception handler",
+		exception_mnemonic(svm_exception_test_vector));
+	vmmcall();
+}
+
+static void handle_exception_in_l2(u8 vector)
+{
+	handler old_handler = handle_exception(vector, svm_exception_handler);
+	svm_exception_test_vector = vector;
+
+	report(svm_vmrun() == SVM_EXIT_VMMCALL,
+		"%s handled by L2", exception_mnemonic(vector));
+
+	handle_exception(vector, old_handler);
+}
+
+static void handle_exception_in_l1(u32 vector)
+{
+	u32 old_ie = vmcb->control.intercept_exceptions;
+
+	vmcb->control.intercept_exceptions |= (1ULL << vector);
+
+	report(svm_vmrun() == (SVM_EXIT_EXCP_BASE + vector),
+		"%s handled by L1",  exception_mnemonic(vector));
+
+	vmcb->control.intercept_exceptions = old_ie;
+}
+
+static void svm_exception_test(void)
+{
+	struct svm_exception_test *t;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(svm_exception_tests); i++) {
+		t = &svm_exception_tests[i];
+		test_set_guest((test_guest_func)t->guest_code);
+
+		handle_exception_in_l2(t->vector);
+		vmcb_ident(vmcb);
+
+		handle_exception_in_l1(t->vector);
+		vmcb_ident(vmcb);
+	}
+}
+
 struct svm_test svm_tests[] = {
 	{ "null", default_supported, default_prepare,
 	  default_prepare_gif_clear, null_test,
@@ -3389,6 +3465,7 @@ struct svm_test svm_tests[] = {
 	TEST(svm_nm_test),
 	TEST(svm_int3_test),
 	TEST(svm_into_test),
+	TEST(svm_exception_test),
 	TEST(svm_lbrv_test0),
 	TEST(svm_lbrv_test1),
 	TEST(svm_lbrv_test2),
-- 
2.38.0.rc1.362.ged0d419d3c-goog