Index: sys/x86/xen/pv.c
===================================================================
--- sys/x86/xen/pv.c
+++ sys/x86/xen/pv.c
@@ -76,6 +76,7 @@
 #include <xen/xenstore/xenstorevar.h>
 #include <xen/xen_pv.h>
 
+#include <contrib/xen/arch-x86/cpuid.h>
 #include <contrib/xen/arch-x86/hvm/start_info.h>
 #include <contrib/xen/vcpu.h>
 
@@ -117,6 +118,35 @@
 
 /*-------------------------------- Xen PV init -------------------------------*/
 
+static int
+isxen(void)
+{
+	u_int regs[4];
+
+	/*
+	 * The full code for identifying which hypervisor we're running under
+	 * is in sys/x86/x86/identcpu.c and runs later in the boot process;
+	 * this is sufficient to distinguish Xen PVH booting from non-Xen PVH
+	 * and skip some very early Xen-specific code in the non-Xen case.
+	 */
+	do_cpuid(0x40000000, regs);
+	if (regs[1] == XEN_CPUID_SIGNATURE_EBX &&
+	    regs[2] == XEN_CPUID_SIGNATURE_ECX &&
+	    regs[3] == XEN_CPUID_SIGNATURE_EDX)
+		return (1);
+	else
+		return (0);
+}
+
+#define CRASH(...) do {					\
+	if (isxen()) {					\
+		xc_printf(__VA_ARGS__);			\
+		HYPERVISOR_shutdown(SHUTDOWN_crash);	\
+	} else {					\
+		halt();					\
+	}						\
+} while (0)
+
 uint64_t
 hammer_time_xen(vm_paddr_t start_info_paddr)
 {
@@ -126,21 +156,20 @@
 	char *kenv;
 	int rc;
 
-	xen_domain_type = XEN_HVM_DOMAIN;
-	vm_guest = VM_GUEST_XEN;
-
-	rc = xen_hvm_init_hypercall_stubs(XEN_HVM_INIT_EARLY);
-	if (rc) {
-		xc_printf("ERROR: failed to initialize hypercall page: %d\n",
-		    rc);
-		HYPERVISOR_shutdown(SHUTDOWN_crash);
+	if (isxen()) {
+		xen_domain_type = XEN_HVM_DOMAIN;
+		vm_guest = VM_GUEST_XEN;
+		rc = xen_hvm_init_hypercall_stubs(XEN_HVM_INIT_EARLY);
+		if (rc) {
+			CRASH("ERROR: failed to initialize hypercall page: %d\n",
+			    rc);
+		}
 	}
 
 	start_info = (struct hvm_start_info *)(start_info_paddr + KERNBASE);
 	if (start_info->magic != XEN_HVM_START_MAGIC_VALUE) {
-		xc_printf("Unknown magic value in start_info struct: %#x\n",
+		CRASH("Unknown magic value in start_info struct: %#x\n",
 		    start_info->magic);
-		HYPERVISOR_shutdown(SHUTDOWN_crash);
 	}
 
 	/*
@@ -164,9 +193,8 @@
 		unsigned int i;
 
 		if (start_info->nr_modules == 0) {
-			xc_printf(
+			CRASH(
 			    "ERROR: modlist_paddr != 0 but nr_modules == 0\n");
-			HYPERVISOR_shutdown(SHUTDOWN_crash);
 		}
 		mod = (struct hvm_modlist_entry *)
 		    (start_info->modlist_paddr + KERNBASE);
@@ -175,16 +203,16 @@
 			    PAGE_SIZE), physfree);
 	}
 
-	xatp.domid = DOMID_SELF;
-	xatp.idx = 0;
-	xatp.space = XENMAPSPACE_shared_info;
-	xatp.gpfn = atop(physfree);
-	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) {
-		xc_printf("ERROR: failed to setup shared_info page\n");
-		HYPERVISOR_shutdown(SHUTDOWN_crash);
+	if (isxen()) {
+		xatp.domid = DOMID_SELF;
+		xatp.idx = 0;
+		xatp.space = XENMAPSPACE_shared_info;
+		xatp.gpfn = atop(physfree);
+		if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
+			CRASH("ERROR: failed to setup shared_info page\n");
+		HYPERVISOR_shared_info = (shared_info_t *)(physfree + KERNBASE);
+		physfree += PAGE_SIZE;
 	}
-	HYPERVISOR_shared_info = (shared_info_t *)(physfree + KERNBASE);
-	physfree += PAGE_SIZE;
 
 	/*
 	 * Init a static kenv using a free page. The contents will be filled
@@ -245,7 +273,7 @@
 
 		value = option;
 		option = strsep(&value, "=");
-		if (kern_setenv(option, value) != 0)
+		if (kern_setenv(option, value) != 0 && isxen())
 			xc_printf("unable to add kenv %s=%s\n", option, value);
 		option = value + strlen(value) + 1;
 	}
@@ -269,7 +297,8 @@
 	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) ||
 	    ehdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
 	    ehdr->e_version > 1) {
-		xc_printf("Unable to load ELF symtab: invalid symbol table\n");
+		if (isxen())
+			xc_printf("Unable to load ELF symtab: invalid symbol table\n");
 		return;
 	}
 
@@ -290,7 +319,8 @@
 	}
 
 	if (ksymtab == 0 || kstrtab == 0)
-		xc_printf(
+		if (isxen())
+			xc_printf(
     "Unable to load ELF symtab: could not find symtab or strtab\n");
 }
 #endif
@@ -320,8 +350,7 @@
 
 			if ((header->flags & XENHEADER_HAS_MODULEP_OFFSET) !=
 			    XENHEADER_HAS_MODULEP_OFFSET) {
-				xc_printf("Unable to load module metadata\n");
-				HYPERVISOR_shutdown(SHUTDOWN_crash);
+				CRASH("Unable to load module metadata\n");
 			}
 
 			preload_metadata = (caddr_t)(mod[0].paddr +
@@ -331,8 +360,7 @@
 			if (kmdp == NULL)
 				kmdp = preload_search_by_type("elf64 kernel");
 			if (kmdp == NULL) {
-				xc_printf("Unable to find kernel\n");
-				HYPERVISOR_shutdown(SHUTDOWN_crash);
+				CRASH("Unable to find kernel\n");
 			}
 
 			/*
@@ -353,8 +381,7 @@
 			if (kmdp == NULL)
 				kmdp = preload_search_by_type("elf64 kernel");
 			if (kmdp == NULL) {
-				xc_printf("Unable to find kernel\n");
-				HYPERVISOR_shutdown(SHUTDOWN_crash);
+				CRASH("Unable to find kernel\n");
 			}
 
 			metadata = MD_FETCH(kmdp, MODINFOMD_MODULEP, vm_paddr_t);
@@ -436,9 +463,8 @@
 	set_xen_guest_handle(memmap.buffer, xen_smap);
 	rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
 	if (rc) {
-		xc_printf("ERROR: unable to fetch Xen E820 memory map: %d\n",
+		CRASH("ERROR: unable to fetch Xen E820 memory map: %d\n",
 		    rc);
-		HYPERVISOR_shutdown(SHUTDOWN_crash);
 	}
 
 	size = memmap.nr_entries * sizeof(xen_smap[0]);