Re: [PATCH] [v2] linux: virtio: Standardize virtio's concept of "page size"

[Hollis Blanchard <hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>]

On Thu, 2008-11-13 at 08:44 +1030, Rusty Russell wrote:
> 
> Note that I still don't have a balloon patch: want to send me one?

qemu: virtio-balloon: don't use TARGET_PAGE_BITS in balloon interface

Make the balloon interface always use 4K pages.

Signed-off-by: Hollis Blanchard <hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
---
Only build-tested.

diff --git a/qemu/hw/virtio-balloon.c b/qemu/hw/virtio-balloon.c
--- a/qemu/hw/virtio-balloon.c
+++ b/qemu/hw/virtio-balloon.c
@@ -87,7 +87,7 @@ static void virtio_balloon_handle_output
 	    ram_addr_t pa;
 	    ram_addr_t addr;
 
-	    pa = (ram_addr_t)ldl_p(&pfn) << TARGET_PAGE_BITS;
+	    pa = (ram_addr_t)ldl_p(&pfn) << VIRTIO_BALLOON_PFN_SHIFT;
 	    offset += 4;
 
 	    addr = cpu_get_physical_page_desc(pa);
@@ -135,11 +135,11 @@ static ram_addr_t virtio_balloon_to_targ
 	target = ram_size;
 
     if (target) {
-	dev->num_pages = (ram_size - target) >> TARGET_PAGE_BITS;
+	dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
 	virtio_notify_config(&dev->vdev);
     }
 
-    return ram_size - (dev->actual << TARGET_PAGE_BITS);
+    return ram_size - (dev->actual << VIRTIO_BALLOON_PFN_SHIFT);
 }
 
 static void virtio_balloon_save(QEMUFile *f, void *opaque)
diff --git a/qemu/hw/virtio-balloon.h b/qemu/hw/virtio-balloon.h
--- a/qemu/hw/virtio-balloon.h
+++ b/qemu/hw/virtio-balloon.h
@@ -23,6 +23,9 @@
 /* The feature bitmap for virtio balloon */
 #define VIRTIO_BALLOON_F_MUST_TELL_HOST	0 /* Tell before reclaiming pages */
 
+/* Size of a PFN in the balloon interface. */
+#define VIRTIO_BALLOON_PFN_SHIFT 12
+
 struct virtio_balloon_config
 {
     /* Number of pages host wants Guest to give up. */

-- 
Hollis Blanchard
IBM Linux Technology Center

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