--- linux-2.6.16-mtyrel-k8-64bit-xen/arch/i386/kernel/cpu/cpufreq/powernow-k8.c~	2006-03-28 13:52:05.553985250 -0500
+++ linux-2.6.16-mtyrel-k8-64bit-xen/arch/i386/kernel/cpu/cpufreq/powernow-k8.c	2006-03-29 18:30:17.260355500 -0500
@@ -48,6 +48,37 @@
 #define VERSION "version 1.60.0"
 #include "powernow-k8.h"
 
+/* Xen support */
+
+#ifdef CONFIG_XEN_PRIVILEGED_GUEST
+int xen_access_msr(u32 msr, int write, u32* out1, u32* out2, u32 in1, u32 in2) {
+	dom0_op_t op;
+	op.cmd = DOM0_MSR;
+  op.u.msr.write = write;
+  op.u.msr.cpu_mask = 1; /* only first CPU: not clear how to read multiple CPUs */
+  op.u.msr.msr = msr;
+  op.u.msr.in1 = in1;
+  op.u.msr.in2 = in2;
+	BUG_ON(HYPERVISOR_dom0_op(&op));
+
+  if (!write) {
+    *out1 = op.u.msr.out1; /* low 32 bits */
+    *out2 = op.u.msr.out2; /* high 32 bits */
+  }
+
+  return 0;
+}
+
+#define cpu_rdmsr(msr, val1, val2) xen_access_msr((msr), 0, &(val1), &(val2), 0, 0)
+#define cpu_wrmsr(msr, val1, val2) xen_access_msr((msr), 1, NULL, NULL, (val1), (val2))
+
+#else
+
+#define cpu_rdmsr(msr, val1, val2) rdmsr(msr, val1, val2)
+#define cpu_wrmsr(msr, val1, val2) wrmsr(msr, val1, val2)
+
+#endif
+
 /* serialize freq changes  */
 static DECLARE_MUTEX(fidvid_sem);
 
@@ -98,7 +129,7 @@
 {
 	u32 lo, hi;
 
-	rdmsr(MSR_FIDVID_STATUS, lo, hi);
+	cpu_rdmsr(MSR_FIDVID_STATUS, lo, hi);
 	return lo & MSR_S_LO_CHANGE_PENDING ? 1 : 0;
 }
 
@@ -116,7 +147,7 @@
 			dprintk("detected change pending stuck\n");
 			return 1;
 		}
-		rdmsr(MSR_FIDVID_STATUS, lo, hi);
+		cpu_rdmsr(MSR_FIDVID_STATUS, lo, hi);
 	} while (lo & MSR_S_LO_CHANGE_PENDING);
 
 	data->currvid = hi & MSR_S_HI_CURRENT_VID;
@@ -145,13 +176,13 @@
 	u32 lo, hi;
 	u8 fid, vid;
 
-	rdmsr(MSR_FIDVID_STATUS, lo, hi);
+	cpu_rdmsr(MSR_FIDVID_STATUS, lo, hi);
 	vid = hi & MSR_S_HI_CURRENT_VID;
 	fid = lo & MSR_S_LO_CURRENT_FID;
 	lo = fid | (vid << MSR_C_LO_VID_SHIFT);
 	hi = MSR_C_HI_STP_GNT_BENIGN;
 	dprintk("cpu%d, init lo 0x%x, hi 0x%x\n", smp_processor_id(), lo, hi);
-	wrmsr(MSR_FIDVID_CTL, lo, hi);
+	cpu_wrmsr(MSR_FIDVID_CTL, lo, hi);
 }
 
 
@@ -173,7 +204,7 @@
 		fid, lo, data->plllock * PLL_LOCK_CONVERSION);
 
 	do {
-		wrmsr(MSR_FIDVID_CTL, lo, data->plllock * PLL_LOCK_CONVERSION);
+		cpu_wrmsr(MSR_FIDVID_CTL, lo, data->plllock * PLL_LOCK_CONVERSION);
 		if (i++ > 100) {
 			printk(KERN_ERR PFX "internal error - pending bit very stuck - no further pstate changes possible\n");
 			return 1;
@@ -215,7 +246,7 @@
 		vid, lo, STOP_GRANT_5NS);
 
 	do {
-		wrmsr(MSR_FIDVID_CTL, lo, STOP_GRANT_5NS);
+		cpu_wrmsr(MSR_FIDVID_CTL, lo, STOP_GRANT_5NS);
 		if (i++ > 100) {
 			printk(KERN_ERR PFX "internal error - pending bit very stuck - no further pstate changes possible\n");
 			return 1;
@@ -294,7 +325,7 @@
 		smp_processor_id(),
 		data->currfid, data->currvid, reqvid, data->rvo);
 
-	rdmsr(MSR_FIDVID_STATUS, lo, maxvid);
+	cpu_rdmsr(MSR_FIDVID_STATUS, lo, maxvid);
 	maxvid = 0x1f & (maxvid >> 16);
 	dprintk("ph1 maxvid=0x%x\n", maxvid);
 	if (reqvid < maxvid) /* lower numbers are higher voltages */