Improve documentation and error handling around FEP

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

diff --git a/arch/x86/setup.c b/arch/x86/setup.c
index d1c42d3dfc4f4e639c7492c2ba298df570aa8dc9..3e79226fb2649f277a8ab01244d7c2399c3a2afc 100644 (file)
--- a/arch/x86/setup.c
+++ b/arch/x86/setup.c
@@ -229,7 +229,10 @@ void test_setup(void)
                   : "0" (false));
 
     if ( test_needs_fep && !xtf_has_fep )
-        return xtf_skip("FEP unavailable, but needed by test\n");
+    {
+        printk("FEP unavailable, but needed by test. (Is Xen support\n");
+        return xtf_skip("compiled in, and booted with 'hvm_fep'?)\n");
+    }
 }
 
 /*

diff --git a/docs/mainpage.dox b/docs/mainpage.dox
index c3257f52c823a41645cf32c54db2daf5793be6a8..91909e81d7ca89a04bbed0a8dc170720ca99c646 100644 (file)
--- a/docs/mainpage.dox
+++ b/docs/mainpage.dox
@@ -85,6 +85,12 @@ To run tests on a Xen host: (see @ref errata first)
   elsewhere, use `make install DESTDIR=$X xtfdir=$Y` to configure absolute
   paths appropriately for the test system.
 
+- Some tests require the Xen Force Emulation Prefix to function.  FEP
+  deliberately opens the x86 instruction emulator to arbitrary testing, and
+  should not be enabled in production.  These tests must be run on a
+  hypervisor configured with `CONFIG_HVM_FEP` and booted with `'hvm_fep'` to
+  enable the runtime use of FEP.  These tests will detect if FEP is
+  unavailable and exit with an error.
 
 @section further Further Information