[kvm-unit-tests PATCH v5 2/4] x86: Add support for running a nested guest multiple times in one test

[Aaron Lewis <aaronlewis@google.com>]

KUT has a limit of only being able to run one nested guest per vmx test.
This is limiting and not necessary.  Add support for allowing a test to
run guest code multiple times.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
---
 x86/vmx.c | 19 +++++++++++++++++--
 x86/vmx.h |  1 +
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/x86/vmx.c b/x86/vmx.c
index f4fbb94..b2d8393 100644
--- a/x86/vmx.c
+++ b/x86/vmx.c
@@ -1884,15 +1884,30 @@ void test_add_teardown(test_teardown_func func, void *data)
 	step->data = data;
 }
 
+static void __test_set_guest(test_guest_func func)
+{
+	assert(current->v2);
+	v2_guest_main = func;
+}
+
 /*
  * Set the target of the first enter_guest call. Can only be called once per
  * test. Must be called before first enter_guest call.
  */
 void test_set_guest(test_guest_func func)
 {
-	assert(current->v2);
 	TEST_ASSERT_MSG(!v2_guest_main, "Already set guest func.");
-	v2_guest_main = func;
+	__test_set_guest(func);
+}
+
+/*
+ * Set the target of the enter_guest call and reset the RIP so 'func' will
+ * start from the beginning.  This can be called multiple times per test.
+ */
+void test_override_guest(test_guest_func func)
+{
+	__test_set_guest(func);
+	init_vmcs_guest();
 }
 
 static void check_for_guest_termination(union exit_reason exit_reason)
diff --git a/x86/vmx.h b/x86/vmx.h
index 4423986..dabd5da 100644
--- a/x86/vmx.h
+++ b/x86/vmx.h
@@ -1055,6 +1055,7 @@ void hypercall(u32 hypercall_no);
 typedef void (*test_guest_func)(void);
 typedef void (*test_teardown_func)(void *data);
 void test_set_guest(test_guest_func func);
+void test_override_guest(test_guest_func func);
 void test_add_teardown(test_teardown_func func, void *data);
 void test_skip(const char *msg);
 
-- 
2.35.0.rc0.227.g00780c9af4-goog