[PATCH 5/24] [xen-unstable.hg] make consoled use grantref rather than map_foreign_range (which only privileged domains can do)

[Alex Zeffertt <alex.zeffertt@eu.citrix.com>]

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This patch modifies the console daemon to use xc_gnttab_map_grant_ref
instead of xc_map_foreign_range where available.

TODO: This will probably break linking on Solaris, since they don't have
stubs for the gntmap functions yet.

A previous version of this patch was sent to xen-devel. See
http://lists.xensource.com/archives/html/xen-devel/2008-07/msg00610.html

Signed-off-by: Diego Ongaro <diego.ongaro@citrix.com>
Signed-off-by: Alex Zeffertt <alex.zeffertt@eu.citrix.com>
---

diff -r 5c5e30d44696 tools/console/daemon/io.c
--- a/tools/console/daemon/io.c	Fri Aug 01 16:50:29 2008 +0100
+++ b/tools/console/daemon/io.c	Fri Aug 01 16:50:30 2008 +0100
@@ -25,6 +25,7 @@
 #include <xs.h>
 #include <xen/io/console.h>
 #include <xenctrl.h>
+#include <xen/grant_table.h>
 
 #include <stdlib.h>
 #include <errno.h>
@@ -538,12 +539,22 @@
 		goto out;
 
 	if (ring_ref != dom->ring_ref) {
-		if (dom->interface != NULL)
-			munmap(dom->interface, getpagesize());
-		dom->interface = xc_map_foreign_range(
-			xc, dom->domid, getpagesize(),
-			PROT_READ|PROT_WRITE,
-			(unsigned long)ring_ref);
+		if (xcg >= 0) {
+			/* this is the preferred method */
+			if (dom->interface != NULL)
+				xc_gnttab_munmap(xcg, dom->interface, 1);
+			dom->interface = xc_gnttab_map_grant_ref(
+				xcg, dom->domid,
+				GNTTAB_RESERVED_CONSOLE,
+				PROT_READ|PROT_WRITE);
+		} else {
+			if (dom->interface != NULL)
+				munmap(dom->interface, getpagesize());
+			dom->interface = xc_map_foreign_range(
+				xc, dom->domid, getpagesize(),
+				PROT_READ|PROT_WRITE,
+				(unsigned long)ring_ref);
+		}
 		if (dom->interface == NULL) {
 			err = EINVAL;
 			goto out;
@@ -736,9 +747,13 @@
 {
 	d->is_dead = true;
 	watch_domain(d, false);
-	if (d->interface != NULL)
-		munmap(d->interface, getpagesize());
-	d->interface = NULL;
+	if (d->interface != NULL) {
+		if (xcg >= 0)
+			xc_gnttab_munmap(xcg, d->interface, 1);
+		else
+			munmap(d->interface, getpagesize());
+		d->interface = NULL;
+	}
 	if (d->xce_handle != -1)
 		xc_evtchn_close(d->xce_handle);
 	d->xce_handle = -1;
diff -r 5c5e30d44696 tools/console/daemon/utils.c
--- a/tools/console/daemon/utils.c	Fri Aug 01 16:50:29 2008 +0100
+++ b/tools/console/daemon/utils.c	Fri Aug 01 16:50:30 2008 +0100
@@ -38,7 +38,8 @@
 #include "utils.h"
 
 struct xs_handle *xs;
-int xc;
+int xc = -1;
+int xcg = -1;
 
 static void child_exit(int sig)
 {
@@ -122,6 +123,11 @@
 		goto out;
 	}
 
+	xcg = xc_gnttab_open();
+	if (xcg == -1) {
+		dolog(LOG_WARNING, "Failed to open gnttab (%m)");
+	}
+
 	if (!xs_watch(xs, "@introduceDomain", "domlist")) {
 		dolog(LOG_ERR, "xenstore watch on @introduceDomain fails.");
 		goto out;
@@ -139,6 +145,8 @@
 		xs_daemon_close(xs);
 	if (xc != -1)
 		xc_interface_close(xc);
+	if (xcg != -1)
+		xc_gnttab_close(xcg);
 	return false;
 }
 
diff -r 5c5e30d44696 tools/console/daemon/utils.h
--- a/tools/console/daemon/utils.h	Fri Aug 01 16:50:29 2008 +0100
+++ b/tools/console/daemon/utils.h	Fri Aug 01 16:50:30 2008 +0100
@@ -32,6 +32,7 @@
 
 extern struct xs_handle *xs;
 extern int xc;
+extern int xcg;
 
 #if 1
 #define dolog(val, fmt, ...) do {				\



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