Index: sys/boot/i386/libi386/i386_module.c
===================================================================
--- sys/boot/i386/libi386/i386_module.c
+++ sys/boot/i386/libi386/i386_module.c
@@ -32,12 +32,53 @@
  *
  */
 
+#include <stand.h>
+#include <string.h>
+#include <machine/cpufunc.h>
+
+static char hv_vendor[16];
+
+/*
+ * See Section 3.2 Hypervisor Discovery of Hyper-V's Hypervisor Top Level
+ * Functional Specification or the kernel's function identify_hypervisor().
+ */
+int running_on_hyperv(void)
+{
+    unsigned int regs[4];
+
+    do_cpuid(1, regs);
+    if (!(regs[2] & 0x80000000))
+        return (0);
+
+    do_cpuid(0x40000000, regs);
+    if (regs[0] < 0x40000000)
+        return (0);
+
+    ((unsigned int *)&hv_vendor)[0] = regs[1];
+    ((unsigned int *)&hv_vendor)[1] = regs[2];
+    ((unsigned int *)&hv_vendor)[2] = regs[3];
+    hv_vendor[12] = '\0';
+
+    if (strcmp(hv_vendor, "Microsoft Hv") != 0)
+        return (0);
+
+    return (1);
+}
+
 /*
  * Use voodoo to load modules required by current hardware.
  */
 int
 i386_autoload(void)
 {
+    if (running_on_hyperv()) {
+		/*
+		 * vt(4) is pretty slow in graphics mode when FreeBSD guest runs on
+		 * Hyper-V, but luckily it is fast enough in text mode.
+		 */
+        if (getenv("hw.vga.textmode") == NULL)
+            setenv("hw.vga.textmode", "1", 1);
+    }
 
     /* XXX use PnP to locate stuff here */
     return(0);