[kvm-unit-tests,3/3] x86: nSVM: Check #OF exception handling in L2

Commit Message

Manali Shukla Dec. 29, 2021, 6:22 a.m. UTC

Add coverage for OF exception handling in L2 when only L2 OF
exception handler is registered.

OF exception generated using instrumented code and it is handled
by L2 OF exception handler.

Signed-off-by: Manali Shukla <[e-mail]>
---
 x86/svm_tests.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

Patch

diff --git a/x86/svm_tests.c b/x86/svm_tests.c
index ed67ae1..0707786 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -2962,6 +2962,53 @@  static bool vgif_check(struct svm_test *test)
     return get_test_stage(test) == 3;
 }
 
+static int of_test_counter;
+
+static void guest_test_of_handler(struct ex_regs *r)
+{
+    of_test_counter++;
+}
+
+static void svm_of_test_guest(struct svm_test *test)
+{
+    struct far_pointer32 fp = {
+        .offset = (uintptr_t)&&into,
+        .selector = KERNEL_CS32,
+    };
+    uintptr_t rsp;
+
+    asm volatile ("mov %%rsp, %0" : "=r"(rsp));
+
+    if (fp.offset != (uintptr_t)&&into) {
+        printf("Codee address too high.\n");
+        return;
+    }
+
+    if ((u32)rsp != rsp) {
+        printf("Stack address too high.\n");
+    }
+
+    asm goto("lcall *%0" : : "m" (fp) : "rax" : into);
+    return;
+into:
+
+    asm volatile (".code32;"
+            "movl $0x7fffffff, %eax;"
+            "addl %eax, %eax;"
+            "into;"
+            "lret;"
+            ".code64");
+    __builtin_unreachable();
+}
+
+static void svm_into_test(void)
+{
+    handle_exception(OF_VECTOR, guest_test_of_handler);
+    test_set_guest(svm_of_test_guest);
+    report(svm_vmrun() == SVM_EXIT_VMMCALL && of_test_counter == 1,
+        "#OF is generated in L2 exception handler0");
+}
+
 static int bp_test_counter;
 
 static void guest_test_bp_handler(struct ex_regs *r)
@@ -3148,5 +3195,6 @@  struct svm_test svm_tests[] = {
     TEST(svm_test_singlestep),
     TEST(svm_nm_test),
     TEST(svm_int3_test),
+    TEST(svm_into_test),
     { NULL, NULL, NULL, NULL, NULL, NULL, NULL }
 };