hvm: Do not crash guest if it does an unaligned access to an HPET

register. Some CrashMe test apaprently does this and we don't want
that to crash the domain it runs in.
From: Dexuan Cui <dexuan.cui@intel.com>
Signed-off-by: Keir Fraser <keir.fraser@eu.citrix.com>
xen-unstable changeset:   16404:ae6f4c7f15cbc2a7192c91e513682e3d13de9f4f
xen-unstable date:        Wed Nov 21 09:49:09 2007 +0000

diff --git a/xen/arch/x86/hvm/hpet.c b/xen/arch/x86/hvm/hpet.c
index 2b8935b47fda07ae201545e4cccfd296e09b705b..cf2737e994479b9b16b4afa1027411c93c506fdb 100644 (file)
--- a/xen/arch/x86/hvm/hpet.c
+++ b/xen/arch/x86/hvm/hpet.c
@@ -102,9 +102,13 @@ static inline int hpet_check_access_length(
 {
     if ( (addr & (len - 1)) || (len > 8) )
     {
-        gdprintk(XENLOG_ERR, "HPET: access across register boundary: "
+        /*
+         * According to ICH9 specification, unaligned accesses may result
+         * in unexpected behaviour or master abort, but should not crash/hang.
+         * Hence we read all-ones, drop writes, and log a warning.
+         */
+        gdprintk(XENLOG_WARNING, "HPET: access across register boundary: "
                  "%lx %lx\n", addr, len);
-        domain_crash(current->domain);
         return -EINVAL;
     }