diff --git a/Makefile.target b/Makefile.target
index 40cc592..2c8e1b8 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -202,6 +202,8 @@ obj-$(CONFIG_NO_KVM) += kvm-stub.o
 obj-y += memory.o
 LIBS+=-lz
 
+obj-$(CONFIG_HYPERV) += hyperv.o
+
 QEMU_CFLAGS += $(VNC_TLS_CFLAGS)
 QEMU_CFLAGS += $(VNC_SASL_CFLAGS)
 QEMU_CFLAGS += $(VNC_JPEG_CFLAGS)
diff --git a/default-configs/i386-softmmu.mak b/default-configs/i386-softmmu.mak
index 55589fa..ee69a0a 100644
--- a/default-configs/i386-softmmu.mak
+++ b/default-configs/i386-softmmu.mak
@@ -21,3 +21,4 @@ CONFIG_PIIX_PCI=y
 CONFIG_SOUND=y
 CONFIG_HPET=y
 CONFIG_APPLESMC=y
+CONFIG_HYPERV=y
diff --git a/default-configs/x86_64-softmmu.mak b/default-configs/x86_64-softmmu.mak
index 8895028..35b1c00 100644
--- a/default-configs/x86_64-softmmu.mak
+++ b/default-configs/x86_64-softmmu.mak
@@ -21,3 +21,4 @@ CONFIG_PIIX_PCI=y
 CONFIG_SOUND=y
 CONFIG_HPET=y
 CONFIG_APPLESMC=y
+CONFIG_HYPERV=y
diff --git a/target-i386/cpuid.c b/target-i386/cpuid.c
index 1e8bcff..50b2d0e 100644
--- a/target-i386/cpuid.c
+++ b/target-i386/cpuid.c
@@ -27,6 +27,8 @@
 #include "qemu-option.h"
 #include "qemu-config.h"
 
+#include "hyperv.h"
+
 /* feature flags taken from "Intel Processor Identification and the CPUID
  * Instruction" and AMD's "CPUID Specification".  In cases of disagreement
  * between feature naming conventions, aliases may be added.
@@ -716,6 +718,14 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
                     goto error;
                 }
                 x86_cpu_def->tsc_khz = tsc_freq / 1000;
+            } else if (!strcmp(featurestr, "hv_spinlocks")) {
+               char* err;
+               numvalue = strtoul(val, &err, 0);
+               if (!*val || *err) {
+                    fprintf(stderr, "bad numerical value %s\n", val);
+                    goto error;
+                }
+                hyperv_set_spinlock_retries(numvalue);
             } else {
                 fprintf(stderr, "unrecognized feature %s\n", featurestr);
                 goto error;
@@ -724,6 +734,10 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
             check_cpuid = 1;
         } else if (!strcmp(featurestr, "enforce")) {
             check_cpuid = enforce_cpuid = 1;
+        } else if (!strcmp(featurestr, "hv_relaxed")) {
+            hyperv_set_relaxed_timing(1);
+        } else if (!strcmp(featurestr, "hv_vapic")) {
+            hyperv_set_vapic_recommended(1);            
         } else {
             fprintf(stderr, "feature string `%s' not in format (+feature|-feature|feature=xyz)\n", featurestr);
             goto error;
diff --git a/target-i386/hyperv.c b/target-i386/hyperv.c
new file mode 100644
index 0000000..bed859e
--- /dev/null
+++ b/target-i386/hyperv.c
@@ -0,0 +1,69 @@
+/*
+ * QEMU Hyper-V support
+ *
+ * Copyright Red Hat, Inc. 2011
+ *
+ * Author: Vadim Rozenfeld     <vrozenfe@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "hyperv.h"
+
+static int hyperv_vapic;
+static int hyperv_relaxed_timing;
+static int hyperv_spinlock_attempts = HYPERV_SPINLOCK_NEVER_RETRY;
+
+void hyperv_set_vapic_recommended(int val)
+{
+    hyperv_vapic = val;
+}
+
+void hyperv_set_relaxed_timing(int val)
+{
+    hyperv_relaxed_timing = val;
+}
+
+void hyperv_set_spinlock_retries(int val)
+{
+    hyperv_spinlock_attempts = val;
+    if (hyperv_spinlock_attempts < 0xFFF) {
+        hyperv_spinlock_attempts = 0xFFF;
+    }
+}
+
+int hyperv_enabled(void)
+{
+    return hyperv_hypercall_available() || hyperv_get_relaxed_timing();
+}
+
+int hyperv_hypercall_available(void)
+{
+    if (hyperv_vapic ||
+        (hyperv_spinlock_attempts != HYPERV_SPINLOCK_NEVER_RETRY)) {
+      return 1;
+    }
+    return 0;
+}
+
+int hyperv_get_vapic_recommended(void)
+{
+#ifdef KVM_CAP_IRQCHIP
+    return hyperv_vapic;
+#else
+    return 0;
+#endif
+}
+
+int hyperv_get_relaxed_timing(void)
+{
+    return hyperv_relaxed_timing;
+}
+
+int hyperv_get_spinlock_retries(void)
+{
+    return hyperv_spinlock_attempts;
+}
+
diff --git a/target-i386/hyperv.h b/target-i386/hyperv.h
new file mode 100644
index 0000000..1ea5e99
--- /dev/null
+++ b/target-i386/hyperv.h
@@ -0,0 +1,30 @@
+/*
+ * QEMU Hyper-V support
+ *
+ * Copyright Red Hat, Inc. 2011
+ *
+ * Author: Vadim Rozenfeld     <vrozenfe@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef QEMU_HW_HYPERV_H
+#define QEMU_HW_HYPERV_H 1
+
+#include <asm/hyperv.h>
+
+#define HYPERV_SPINLOCK_NEVER_RETRY             0xFFFFFFFF
+
+void hyperv_set_vapic_recommended(int val);
+void hyperv_set_relaxed_timing(int val);
+void hyperv_set_spinlock_retries(int val);
+
+int hyperv_enabled(void);
+int hyperv_hypercall_available(void);
+int hyperv_get_vapic_recommended(void);
+int hyperv_get_relaxed_timing(void);
+int hyperv_get_spinlock_retries(void);
+
+#endif /* QEMU_HW_HYPERV_H */