x86: vmware: look for DMI string in the product serial key

Impact: Should permit VMware detection on older platforms where the
vendor is changed.  Could theoretically cause a regression if some
weird serial number scheme contains the string "VMware" by pure
chance.  Seems unlikely, especially with the mixed case.

In some user configured cases, VMware may choose not to put a VMware specific
DMI string, but the product serial key is always there and is VMware specific.
Add a interface to check the serial key, when checking for VMware in the DMI
information.
Signed-off-by: Alok N Kataria <akataria@vmware.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/cpu/vmware.c

@@ -61,6 +61,11 @@ static unsigned long __vmware_get_tsc_khz(void)
         return tsc_hz;
 }
 
+/*
+ * While checking the dmi string infomation, just checking the product
+ * serial key should be enough, as this will always have a VMware
+ * specific string when running under VMware hypervisor.
+ */
 int vmware_platform(void)
 {
 	if (cpu_has_hypervisor) {
@@ -74,7 +79,7 @@ int vmware_platform(void)
 		hyper_vendor_id[12] = '\0';
 		if (!strcmp(hyper_vendor_id, "VMwareVMware"))
 			return 1;
-	} else if (dmi_available && dmi_name_in_vendors("VMware") &&
+	} else if (dmi_available && dmi_name_in_serial("VMware") &&
 		   __vmware_platform())
 		return 1;
 

drivers/firmware/dmi_scan.c

@@ -467,6 +467,17 @@ const char *dmi_get_system_info(int field)
 }
 EXPORT_SYMBOL(dmi_get_system_info);
 
+/**
+ *	dmi_name_in_serial - 	Check if string is in the DMI product serial
+ *				information.
+ */
+int dmi_name_in_serial(const char *str)
+{
+	int f = DMI_PRODUCT_SERIAL;
+	if (dmi_ident[f] && strstr(dmi_ident[f], str))
+		return 1;
+	return 0;
+}
 
 /**
  *	dmi_name_in_vendors - Check if string is anywhere in the DMI vendor information.

include/linux/dmi.h

@@ -44,6 +44,7 @@ extern const struct dmi_device * dmi_find_device(int type, const char *name,
 extern void dmi_scan_machine(void);
 extern int dmi_get_year(int field);
 extern int dmi_name_in_vendors(const char *str);
+extern int dmi_name_in_serial(const char *str);
 extern int dmi_available;
 extern int dmi_walk(void (*decode)(const struct dmi_header *));
 
@@ -56,6 +57,7 @@ static inline const struct dmi_device * dmi_find_device(int type, const char *na
 static inline void dmi_scan_machine(void) { return; }
 static inline int dmi_get_year(int year) { return 0; }
 static inline int dmi_name_in_vendors(const char *s) { return 0; }
+static inline int dmi_name_in_serial(const char *s) { return 0; }
 #define dmi_available 0
 static inline int dmi_walk(void (*decode)(const struct dmi_header *))
 	{ return -1; }