From: Rusty Russell <rusty@rustcorp.com.au>

Jeff Garzik argued forcefully that __pa() should not appear in
drivers, and that struct netdevice's irq field should not be used.
Christoph Hellwig suggested that I run sparse, and provide an
lguest-specific wrapper for mapping/unmapping virtual device memory.

Results:
1) send-dma and bind-dma hypercall wrappers for drivers to use,
2) formalization of the convention that devices can use the irq
   corresponding to their index on the lguest_bus.
3) Helper to map and unmap virtual device memory (not classic __iomem).
4) lguest.c should include "lguest_bus.h" for lguest_devices declaration.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/lguest/lguest.c     |   13 +++++++++++++
 drivers/lguest/lguest_bus.c |    2 +-
 include/linux/lguest_bus.h  |    4 ++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff -puN drivers/lguest/lguest.c~lguest-the-guest-code-tidyups-update drivers/lguest/lguest.c
--- a/drivers/lguest/lguest.c~lguest-the-guest-code-tidyups-update
+++ a/drivers/lguest/lguest.c
@@ -36,6 +36,7 @@
 #include <asm/setup.h>
 #include <asm/e820.h>
 #include <asm/mce.h>
+#include <asm/io.h>
 
 /* Declarations for definitions in lguest_guest.S */
 extern char lguest_noirq_start[], lguest_noirq_end[];
@@ -122,6 +123,18 @@ void lguest_unbind_dma(unsigned long key
 	hcall(LHCALL_BIND_DMA, key, __pa(dmas), 0);
 }
 
+/* For guests, device memory can be used as normal memory, so we cast away the
+ * __iomem to quieten sparse. */
+void *lguest_map(unsigned long phys_addr, unsigned long pages)
+{
+	return (__force void *)ioremap(phys_addr, PAGE_SIZE*pages);
+}
+
+void lguest_unmap(void *addr)
+{
+	iounmap((__force void __iomem *)addr);
+}
+
 static unsigned long save_fl(void)
 {
 	return lguest_data.irq_enabled;
diff -puN drivers/lguest/lguest_bus.c~lguest-the-guest-code-tidyups-update drivers/lguest/lguest_bus.c
--- a/drivers/lguest/lguest_bus.c~lguest-the-guest-code-tidyups-update
+++ a/drivers/lguest/lguest_bus.c
@@ -136,7 +136,7 @@ static int __init lguest_bus_init(void)
 		return 0;
 
 	/* Devices are in page above top of "normal" mem. */
-	lguest_devices = (__force void*)ioremap(max_pfn<<PAGE_SHIFT,PAGE_SIZE);
+	lguest_devices = lguest_map(max_pfn<<PAGE_SHIFT, 1);
 
 	if (bus_register(&lguest_bus.bus) != 0
 	    || device_register(&lguest_bus.dev) != 0)
diff -puN include/linux/lguest_bus.h~lguest-the-guest-code-tidyups-update include/linux/lguest_bus.h
--- a/include/linux/lguest_bus.h~lguest-the-guest-code-tidyups-update
+++ a/include/linux/lguest_bus.h
@@ -27,6 +27,10 @@ int lguest_bind_dma(unsigned long key, s
 		    unsigned int num, u8 irq);
 void lguest_unbind_dma(unsigned long key, struct lguest_dma *dmas);
 
+/* Map the virtual device space */
+void *lguest_map(unsigned long phys_addr, unsigned long pages);
+void lguest_unmap(void *);
+
 struct lguest_driver {
 	const char *name;
 	struct module *owner;
_