svn commit: r243349 - projects/bhyve/usr.sbin/bhyve

[Neel Natu]

Author: neel
Date: Wed Nov 21 00:14:03 2012
New Revision: 243349
URL: http://svnweb.freebsd.org/changeset/base/243349

Log:
  Mask the %eax register properly based on whether the "out" instruction is
  operating on 1, 2 or 4 bytes.
  
  There could be garbage in the unused bytes so zero them off.
  
  Obtained from:	NetApp

Modified:
  projects/bhyve/usr.sbin/bhyve/inout.c

Modified: projects/bhyve/usr.sbin/bhyve/inout.c
==============================================================================
--- projects/bhyve/usr.sbin/bhyve/inout.c	Tue Nov 20 21:26:13 2012	(r243348)
+++ projects/bhyve/usr.sbin/bhyve/inout.c	Wed Nov 21 00:14:03 2012	(r243349)
@@ -74,6 +74,7 @@ emulate_inout(struct vmctx *ctx, int vcp
 	      uint32_t *eax, int strict)
 {
 	int flags;
+	uint32_t mask;
 	inout_func_t handler;
 	void *arg;
 
@@ -84,6 +85,21 @@ emulate_inout(struct vmctx *ctx, int vcp
 	if (strict && handler == default_inout)
 		return (-1);
 
+	if (!in) {
+		switch (bytes) {
+		case 1:
+			mask = 0xff;
+			break;
+		case 2:
+			mask = 0xffff;
+			break;
+		default:
+			mask = 0xffffffff;
+			break;
+		}
+		*eax = *eax & mask;
+	}
+
 	flags = inout_handlers[port].flags;
 	arg = inout_handlers[port].arg;