lwp: adding support for AMD lightweight profiling

diff -r b57ee5edd292 -r 20d10f3a6d4c xen/arch/x86/i387.c
@@ -18,36 +18,42 @@
 
 static bool_t __read_mostly cpu_has_xsaveopt;
 
-static void xsave(struct vcpu *v)
+static void xsave(struct vcpu *v, uint64_t mask)
 {
     struct xsave_struct *ptr = v->arch.xsave_area;
+    uint32_t hmask = mask >> 32;
+    uint32_t lmask = mask;
 
     asm volatile (
         ".byte " REX_PREFIX "0x0f,0xae,0x27"
         :
-        : "a" (-1), "d" (-1), "D"(ptr)
+        : "a" (lmask), "d" (hmask), "D"(ptr)
         : "memory" );
 }
 
-static void xsaveopt(struct vcpu *v)
+static void xsaveopt(struct vcpu *v, uint64_t mask)
 {
     struct xsave_struct *ptr = v->arch.xsave_area;
+    uint32_t hmask = mask >> 32;
+    uint32_t lmask = mask;
 
     asm volatile (
         ".byte " REX_PREFIX "0x0f,0xae,0x37"
         :
-        : "a" (-1), "d" (-1), "D"(ptr)
+        : "a" (lmask), "d" (hmask), "D"(ptr)
         : "memory" );
 }
 
-static void xrstor(struct vcpu *v)
+static void xrstor(struct vcpu *v, uint64_t mask)
 {
     struct xsave_struct *ptr = v->arch.xsave_area;
+    uint32_t hmask = mask >> 32;
+    uint32_t lmask = mask;
 
     asm volatile (
         ".byte " REX_PREFIX "0x0f,0xae,0x2f"
         :
-        : "m" (*ptr), "a" (-1), "d" (-1), "D"(ptr) );
+        : "m" (*ptr), "a" (lmask), "d" (hmask), "D"(ptr) );
 }
 
 static void load_mxcsr(unsigned long val)

@@ -76,7 +82,7 @@
          * we set all supported feature mask before doing save/restore.
          */
         set_xcr0(v->arch.xcr0_accum);
-        xrstor(v);
+        xrstor(v, XCNTXT_DEFAULT);
         set_xcr0(v->arch.xcr0);
     }
     else if ( v->fpu_initialised )

@@ -123,9 +129,9 @@
          */
         set_xcr0(v->arch.xcr0_accum);
         if ( cpu_has_xsaveopt )
-            xsaveopt(v);
+            xsaveopt(v, XCNTXT_DEFAULT);
         else
-            xsave(v);
+            xsave(v, XCNTXT_DEFAULT);
         set_xcr0(v->arch.xcr0);
     }
     else if ( cpu_has_fxsr )

diff -r b57ee5edd292 -r 20d10f3a6d4c xen/include/asm-x86/i387.h
@@ -32,6 +32,9 @@
 #define XSTATE_YMM_SIZE    256
 #define XSAVEOPT        (1 << 0)
 
+/* The features that the OS saves/restores by default. */
+#define XCNTXT_DEFAULT     (-1)
+
 struct xsave_struct
 {
     struct { char x[512]; } fpu_sse;         /* FPU/MMX, SSE */