# HG changeset patch
# User Keir Fraser <keir@xxxxxxxxxxxxx>
# Date 1170954266 0
# Node ID 6a383beedf833edded613282e534c451f30bd5f5
# Parent d609929f140809ec1c9a059f2eeaffb7ce56c891
Add example xen-detect.c code for detecting application execution in
Xen PV or HVM contexts, using the Xen CPUID extensions.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
.hgignore | 1
tools/misc/Makefile | 2
tools/misc/xen-detect.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 109 insertions(+), 1 deletion(-)
diff -r d609929f1408 -r 6a383beedf83 .hgignore
--- a/.hgignore Thu Feb 08 16:52:05 2007 +0000
+++ b/.hgignore Thu Feb 08 17:04:26 2007 +0000
@@ -138,6 +138,7 @@
^tools/misc/miniterm/miniterm$
^tools/misc/xc_shadow$
^tools/misc/xen_cpuperf$
+^tools/misc/xen-detect$
^tools/misc/xenperf$
^tools/pygrub/build/.*$
^tools/python/build/.*$
diff -r d609929f1408 -r 6a383beedf83 tools/misc/Makefile
--- a/tools/misc/Makefile Thu Feb 08 16:52:05 2007 +0000
+++ b/tools/misc/Makefile Thu Feb 08 17:04:26 2007 +0000
@@ -9,7 +9,7 @@ CFLAGS += $(INCLUDES)
HDRS = $(wildcard *.h)
-TARGETS = xenperf xc_shadow
+TARGETS = xenperf xc_shadow xen-detect
INSTALL_BIN = $(TARGETS) xencons
INSTALL_SBIN = netfix xm xen-bugtool xen-python-path xend xenperf
diff -r d609929f1408 -r 6a383beedf83 tools/misc/xen-detect.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/misc/xen-detect.c Thu Feb 08 17:04:26 2007 +0000
@@ -0,0 +1,107 @@
+/******************************************************************************
+ * xen_detect.c
+ *
+ * Simple GNU C / POSIX application to detect execution on Xen VMM platform.
+ *
+ * Copyright (c) 2007, XenSource Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+static int pv_context;
+
+static void cpuid(uint32_t idx,
+ uint32_t *eax,
+ uint32_t *ebx,
+ uint32_t *ecx,
+ uint32_t *edx)
+{
+ asm volatile (
+ "test %1,%1 ; jz 1f ; ud2a ; .ascii \"xen\" ; 1: cpuid"
+ : "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx)
+ : "0" (idx), "1" (pv_context) );
+}
+
+static int check_for_xen(void)
+{
+ uint32_t eax, ebx, ecx, edx;
+ char signature[13];
+
+ cpuid(0x40000000, &eax, &ebx, &ecx, &edx);
+ *(uint32_t *)(signature + 0) = ebx;
+ *(uint32_t *)(signature + 4) = ecx;
+ *(uint32_t *)(signature + 8) = edx;
+ signature[12] = '\0';
+
+ if ( strcmp("XenVMMXenVMM", signature) || (eax < 0x40000002) )
+ return 0;
+
+ cpuid(0x40000001, &eax, &ebx, &ecx, &edx);
+ printf("Running in %s context on Xen v%d.%d.\n",
+ pv_context ? "PV" : "HVM", (uint16_t)(eax >> 16), (uint16_t)eax);
+ return 1;
+}
+
+int main(void)
+{
+ pid_t pid;
+ int status;
+ uint32_t dummy;
+
+ /* Check for execution in HVM context. */
+ if ( check_for_xen() )
+ return 0;
+
+ /* Now we check for execution in PV context. */
+ pv_context = 1;
+
+ /*
+ * Fork a child to test the paravirtualised CPUID instruction.
+ * If executed outside Xen PV context, the extended opcode will fault.
+ */
+ pid = fork();
+ switch ( pid )
+ {
+ case 0:
+ /* Child: test paravirtualised CPUID opcode and then exit cleanly. */
+ cpuid(0x40000000, &dummy, &dummy, &dummy, &dummy);
+ exit(0);
+ case -1:
+ fprintf(stderr, "Fork failed.\n");
+ return 0;
+ }
+
+ /*
+ * Parent waits for child to terminate and checks for clean exit.
+ * Only if the exit is clean is it safe for us to try the extended CPUID.
+ */
+ waitpid(pid, &status, 0);
+ if ( WIFEXITED(status) && check_for_xen() )
+ return 0;
+
+ printf("Not running on Xen.\n");
+ return 0;
+}
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