staging: unisys: visorbus: Have unisys_vmcall return Linux error instead of VMCALL error

The function unisys_vmcall was returning VMCALL specific errors and the
calling code was ignoring which error was actually returned. Instead we
should be mapping the VMCALL error into a proper Linux error and then
returning that, since we now have an error we know what to do with, we
don't have to drop it but we can send it up the stack.
Signed-off-by: David Kershner <david.kershner@unisys.com>
Reviewed-by: Reviewed-by: Tim Sell <timothy.sell@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/unisys/visorbus/visorchipset.c

@@ -1371,22 +1371,37 @@ static int unisys_vmcall(unsigned long tuple, unsigned long param)
 	__asm__ __volatile__(".byte 0x00f, 0x001, 0x0c1" : "=a"(result) :
 		"a"(tuple), "b"(reg_ebx), "c"(reg_ecx));
 
-	return result;
+	if (result)
+		goto error;
+
+	return 0;
+
+error: /* Need to convert from VMCALL error codes to Linux */
+	switch (result) {
+	case VMCALL_RESULT_INVALID_PARAM:
+		return -EINVAL;
+	case VMCALL_RESULT_DATA_UNAVAILABLE:
+		return -ENODEV;
+	default:
+		return -EFAULT;
+	}
 }
 static unsigned int
 issue_vmcall_io_controlvm_addr(u64 *control_addr, u32 *control_bytes)
 {
 	struct vmcall_io_controlvm_addr_params params;
-	int result = VMCALL_SUCCESS;
+	int err;
 	u64 physaddr;
 
 	physaddr = virt_to_phys(&params);
-	result = unisys_vmcall(VMCALL_CONTROLVM_ADDR, physaddr);
-	if (VMCALL_SUCCESSFUL(result)) {
-		*control_addr = params.address;
-		*control_bytes = params.channel_bytes;
-	}
-	return result;
+	err = unisys_vmcall(VMCALL_CONTROLVM_ADDR, physaddr);
+	if (err)
+		return err;
+
+	*control_addr = params.address;
+	*control_bytes = params.channel_bytes;
+
+	return 0;
 }
 
 static u64 controlvm_get_channel_address(void)
@@ -1394,7 +1409,7 @@ static u64 controlvm_get_channel_address(void)
 	u64 addr = 0;
 	u32 size = 0;
 
-	if (!VMCALL_SUCCESSFUL(issue_vmcall_io_controlvm_addr(&addr, &size)))
+	if (issue_vmcall_io_controlvm_addr(&addr, &size))
 		return 0;
 
 	return addr;

drivers/staging/unisys/visorbus/vmcallinterface.h

@@ -62,8 +62,14 @@ enum vmcall_monitor_interface_method_tuple { /* VMCALL identification tuples  */
 	VMCALL_UPDATE_PHYSICAL_TIME = 0x0a02
 };
 
-#define VMCALL_SUCCESS 0
-#define VMCALL_SUCCESSFUL(result) (result == 0)
+enum vmcall_result {
+	VMCALL_RESULT_SUCCESS = 0,
+	VMCALL_RESULT_INVALID_PARAM = 1,
+	VMCALL_RESULT_DATA_UNAVAILABLE = 2,
+	VMCALL_RESULT_FAILURE_UNAVAILABLE = 3,
+	VMCALL_RESULT_DEVICE_ERROR = 4,
+	VMCALL_RESULT_DEVICE_NOT_READY = 5
+};
 
 #define unisys_extended_vmcall(tuple, reg_ebx, reg_ecx, reg_edx) \
 	__unisys_extended_vmcall_gnuc(tuple, reg_ebx, reg_ecx, reg_edx)