[Xen-devel] [PATCH] get xenstore buffer in vmx guest

[Xiaofeng Ling <xiaofeng.ling@xxxxxxxxx>]

This patch add support to get xenstore buffer in unmodified vmx guest.
mfn_to_virt it not available in unmodified kernel so use an external 
symbol for it. This symbol will be exported by event channel pci device
driver. The driver will use ioremap to get the access to this page.

Signed-off-by: Xiaofeng Ling <xiaofeng.ling@xxxxxxxxx>
Signed-off-by: Arun Sharma <arun.sharma@xxxxxxxxx>

diff -r 287d36b46fa3 linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_comms.c
--- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_comms.c	Tue Aug 30 
20:36:49 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_comms.c	Fri Sep  2 
22:47:27 2005
@@ -48,12 +48,12 @@

 static inline struct ringbuf_head *outbuf(void)
 {
-       return mfn_to_virt(xen_start_info.store_mfn);
+       return XENSTORE_BUF;
 }

 static inline struct ringbuf_head *inbuf(void)
 {
-       return mfn_to_virt(xen_start_info.store_mfn) + PAGE_SIZE/2;
+       return XENSTORE_BUF + PAGE_SIZE/2;
 }

 static irqreturn_t wake_waiting(int irq, void *unused, struct pt_regs 
*regs)
@@ -218,7 +218,7 @@
        }

        /* FIXME zero out page -- domain builder should probably do this*/
-       memset(mfn_to_virt(xen_start_info.store_mfn), 0, PAGE_SIZE);
+       memset(XENSTORE_BUF, 0, PAGE_SIZE);

        return 0;
 }
diff -r 287d36b46fa3 linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_comms.h
--- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_comms.h	Tue Aug 30 
20:36:49 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_comms.h	Fri Sep  2 
22:47:27 2005
@@ -38,4 +38,11 @@
 int xs_input_avail(void);
 extern wait_queue_head_t xb_waitq;

+#ifdef CONFIG_XEN
+#define XENSTORE_BUF mfn_to_virt(xen_start_info.store_mfn)
+#else
+extern void *shared_xenstore_buf;
+#define XENSTORE_BUF shared_xenstore_buf
+#endif
+
 #endif /* _XENBUS_COMMS_H */
diff -r 287d36b46fa3 linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c
--- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c	Tue Aug 30 
20:36:49 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c	Fri Sep  2 
22:47:27 2005
@@ -648,4 +648,5 @@
        return 0;
 }

-postcore_initcall(xenbus_probe_init);
+module_init(xenbus_probe_init);
+MODULE_LICENSE("GPL");

diff -r 287d36b46fa3 linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_comms.c
--- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_comms.c    Tue Aug 30 
20:36:49 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_comms.c    Fri Sep  2 
22:47:27 2005
@@ -48,12 +48,12 @@
 
 static inline struct ringbuf_head *outbuf(void)
 {
-       return mfn_to_virt(xen_start_info.store_mfn);
+       return XENSTORE_BUF;
 }
 
 static inline struct ringbuf_head *inbuf(void)
 {
-       return mfn_to_virt(xen_start_info.store_mfn) + PAGE_SIZE/2;
+       return XENSTORE_BUF + PAGE_SIZE/2;
 }
 
 static irqreturn_t wake_waiting(int irq, void *unused, struct pt_regs *regs)
@@ -218,7 +218,7 @@
        }
 
        /* FIXME zero out page -- domain builder should probably do this*/
-       memset(mfn_to_virt(xen_start_info.store_mfn), 0, PAGE_SIZE);
+       memset(XENSTORE_BUF, 0, PAGE_SIZE);
 
        return 0;
 }
diff -r 287d36b46fa3 linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_comms.h
--- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_comms.h    Tue Aug 30 
20:36:49 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_comms.h    Fri Sep  2 
22:47:27 2005
@@ -38,4 +38,11 @@
 int xs_input_avail(void);
 extern wait_queue_head_t xb_waitq;
 
+#ifdef CONFIG_XEN
+#define XENSTORE_BUF mfn_to_virt(xen_start_info.store_mfn)
+#else
+extern void *shared_xenstore_buf;
+#define XENSTORE_BUF shared_xenstore_buf
+#endif
+
 #endif /* _XENBUS_COMMS_H */
diff -r 287d36b46fa3 linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c
--- a/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c    Tue Aug 30 
20:36:49 2005
+++ b/linux-2.6-xen-sparse/drivers/xen/xenbus/xenbus_probe.c    Fri Sep  2 
22:47:27 2005
@@ -648,4 +648,5 @@
        return 0;
 }
 
-postcore_initcall(xenbus_probe_init);
+module_init(xenbus_probe_init);
+MODULE_LICENSE("GPL");

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