tools/virtio: add dma stubs

Fixes build after recent IOMMU-related changes,
mustly by adding more stubs.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/tools/virtio/linux/kernel.h b/tools/virtio/linux/kernel.h
index 0338499..d9554fc 100644
--- a/tools/virtio/linux/kernel.h
+++ b/tools/virtio/linux/kernel.h
@@ -20,7 +20,9 @@
 
 #define PAGE_SIZE getpagesize()
 #define PAGE_MASK (~(PAGE_SIZE-1))
+#define PAGE_ALIGN(x) ((x + PAGE_SIZE - 1) & PAGE_MASK)
 
+typedef unsigned long long phys_addr_t;
 typedef unsigned long long dma_addr_t;
 typedef size_t __kernel_size_t;
 typedef unsigned int __wsum;
@@ -57,6 +59,11 @@
 	return p;
 }
 
+static inline void *alloc_pages_exact(size_t s, gfp_t gfp)
+{
+	return kmalloc(s, gfp);
+}
+
 static inline void kfree(void *p)
 {
 	if (p >= __kfree_ignore_start && p < __kfree_ignore_end)
@@ -64,6 +71,11 @@
 	free(p);
 }
 
+static inline void free_pages_exact(void *p, size_t s)
+{
+	kfree(p);
+}
+
 static inline void *krealloc(void *p, size_t s, gfp_t gfp)
 {
 	return realloc(p, s);
@@ -105,6 +117,8 @@
 #define dev_err(dev, format, ...) fprintf (stderr, format, ## __VA_ARGS__)
 #define dev_warn(dev, format, ...) fprintf (stderr, format, ## __VA_ARGS__)
 
+#define WARN_ON_ONCE(cond) ((cond) && fprintf (stderr, "WARNING\n"))
+
 #define min(x, y) ({				\
 	typeof(x) _min1 = (x);			\
 	typeof(y) _min2 = (y);			\