[PATCH 05/13] lib/x86: Move exception test code into library

[Jan Kiszka <jan.kiszka@web.de>]

From: Jan Kiszka <jan.kiszka@siemens.com>

Will also be used by the APIC test. Moving exception_return assignment
out of line, we can drop the explicit compiler barrier.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 lib/x86/desc.c | 24 ++++++++++++++++++++++++
 lib/x86/desc.h |  4 ++++
 x86/vmx.c      | 34 +++++++---------------------------
 3 files changed, 35 insertions(+), 27 deletions(-)

diff --git a/lib/x86/desc.c b/lib/x86/desc.c
index 7c5c721..f75ec1d 100644
--- a/lib/x86/desc.c
+++ b/lib/x86/desc.c
@@ -353,3 +353,27 @@ void print_current_tss_info(void)
                tr, tss[0].prev, tss[i].prev);
 }
 #endif
+
+static bool exception;
+static void *exception_return;
+
+static void exception_handler(struct ex_regs *regs)
+{
+	exception = true;
+	regs->rip = (unsigned long)exception_return;
+}
+
+bool test_for_exception(unsigned int ex, void (*trigger_func)(void *data),
+			void *data)
+{
+	handle_exception(ex, exception_handler);
+	exception = false;
+	trigger_func(data);
+	handle_exception(ex, NULL);
+	return exception;
+}
+
+void set_exception_return(void *addr)
+{
+	exception_return = addr;
+}
diff --git a/lib/x86/desc.h b/lib/x86/desc.h
index f819452..5c850b2 100644
--- a/lib/x86/desc.h
+++ b/lib/x86/desc.h
@@ -84,4 +84,8 @@ void set_intr_task_gate(int e, void *fn);
 void print_current_tss_info(void);
 void handle_exception(u8 v, void (*func)(struct ex_regs *regs));
 
+bool test_for_exception(unsigned int ex, void (*trigger_func)(void *data),
+			void *data);
+void set_exception_return(void *addr);
+
 #endif
diff --git a/x86/vmx.c b/x86/vmx.c
index f9d5493..4f0bb8d 100644
--- a/x86/vmx.c
+++ b/x86/vmx.c
@@ -538,38 +538,18 @@ static void init_vmx(void)
 	memset(guest_syscall_stack, 0, PAGE_SIZE);
 }
 
-static bool exception;
-static void *exception_return;
-
-static void exception_handler(struct ex_regs *regs)
+static void do_vmxon_off(void *data)
 {
-	exception = true;
-	regs->rip = (u64)exception_return;
-}
-
-static int test_for_exception(unsigned int ex, void (*func)(void))
-{
-	handle_exception(ex, exception_handler);
-	exception = false;
-	func();
-	handle_exception(ex, NULL);
-	return exception;
-}
-
-static void do_vmxon_off(void)
-{
-	exception_return = &&resume;
-	barrier();
+	set_exception_return(&&resume);
 	vmx_on();
 	vmx_off();
 resume:
 	barrier();
 }
 
-static void do_write_feature_control(void)
+static void do_write_feature_control(void *data)
 {
-	exception_return = &&resume;
-	barrier();
+	set_exception_return(&&resume);
 	wrmsr(MSR_IA32_FEATURE_CONTROL, 0);
 resume:
 	barrier();
@@ -592,18 +572,18 @@ static int test_vmx_feature_control(void)
 
 	wrmsr(MSR_IA32_FEATURE_CONTROL, 0);
 	report("test vmxon with FEATURE_CONTROL cleared",
-	       test_for_exception(GP_VECTOR, &do_vmxon_off));
+	       test_for_exception(GP_VECTOR, &do_vmxon_off, NULL));
 
 	wrmsr(MSR_IA32_FEATURE_CONTROL, 0x4);
 	report("test vmxon without FEATURE_CONTROL lock",
-	       test_for_exception(GP_VECTOR, &do_vmxon_off));
+	       test_for_exception(GP_VECTOR, &do_vmxon_off, NULL));
 
 	wrmsr(MSR_IA32_FEATURE_CONTROL, 0x5);
 	vmx_enabled = ((rdmsr(MSR_IA32_FEATURE_CONTROL) & 0x5) == 0x5);
 	report("test enable VMX in FEATURE_CONTROL", vmx_enabled);
 
 	report("test FEATURE_CONTROL lock bit",
-	       test_for_exception(GP_VECTOR, &do_write_feature_control));
+	       test_for_exception(GP_VECTOR, &do_write_feature_control, NULL));
 
 	return !vmx_enabled;
 }
-- 
1.8.1.1.298.ge7eed54