[PATCH 07/10] x86/hvm: pkeys, add functions to support PKRU access/write

[Huaitong Han <huaitong.han@intel.com>]

This patch adds functions to support PKRU access/write

Signed-off-by: Huaitong Han <huaitong.han@intel.com>

diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
index f507f5e..427eb84 100644
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -336,6 +336,44 @@ static inline void write_cr4(unsigned long val)
     asm volatile ( "mov %0,%%cr4" : : "r" (val) );
 }
 
+static inline unsigned int read_pkru(void)
+{
+    unsigned int eax, edx;
+    unsigned int ecx = 0;
+    unsigned int pkru;
+
+    asm volatile(".byte 0x0f,0x01,0xee\n\t"
+                 : "=a" (eax), "=d" (edx)
+                 : "c" (ecx));
+    pkru = eax;
+    return pkru;
+}
+
+static inline void write_pkru(unsigned int pkru)
+{
+    unsigned int eax = pkru;
+    unsigned int ecx = 0;
+    unsigned int edx = 0;
+
+    asm volatile(".byte 0x0f,0x01,0xef\n\t"
+                 : : "a" (eax), "c" (ecx), "d" (edx));
+}
+
+/* macros for pkru */
+#define PKRU_READ  0
+#define PKRU_WRITE 1
+#define PKRU_ATTRS 2
+
+/*
+* PKRU defines 32 bits, there are 16 domains and 2 attribute bits per
+* domain in pkru, pkeys is index to a defined domain, so the value of
+* pte_pkeys * PKRU_ATTRS + R/W is offset of a defined domain attribute.
+*/
+#define READ_PKRU_AD(x) ((read_pkru() >> (x * PKRU_ATTRS + PKRU_READ)) & 1)
+#define READ_PKRU_WD(x) ((read_pkru() >> (x * PKRU_ATTRS + PKRU_WRITE)) & 1)
+
+
+
 /* Clear and set 'TS' bit respectively */
 static inline void clts(void) 
 {
-- 
2.4.3