[PATCH] qemu: define and use VIRTIO_PFN_SHIFT

[Hollis Blanchard <hollisb@us.ibm.com>]

# HG changeset patch
# User Hollis Blanchard <hollisb@us.ibm.com>
# Date 1225946837 21600
# Node ID 43a111ea61b542d3823e2a11d017e7b06b7ec254
# Parent  b63967268af119e0faa4adc3086cdef857815548
qemu: define and use VIRTIO_PFN_SHIFT

The virtio front and back ends must agree about how big a pfn really is. Since
qemu has no idea what "page size" the guest may be using, it must be
independent of TARGET_PAGE_BITS.

This patch should have no functional effect on x86 or ia64, but I'd like an ack from the
ia64 guys.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>

diff --git a/qemu/hw/virtio.c b/qemu/hw/virtio.c
--- a/qemu/hw/virtio.c
+++ b/qemu/hw/virtio.c
@@ -56,6 +56,10 @@
  */
 #define wmb() do { } while (0)
 
+#define VRING_PAGE_SIZE (1<<12)
+
+#define ALIGN(x, a)  (((x)+(a)-1) & ~((a)-1))
+
 /* virt queue functions */
 
 static void *virtio_map_gpa(target_phys_addr_t addr, size_t size)
@@ -95,8 +99,8 @@ static void *virtio_map_gpa(target_phys_
 
 static size_t virtqueue_size(int num)
 {
-    return TARGET_PAGE_ALIGN((sizeof(VRingDesc) * num) +
-			     (sizeof(VRingAvail) + sizeof(uint16_t) * num)) +
+    return ALIGN((sizeof(VRingDesc) * num) + (sizeof(VRingAvail) +
+		 sizeof(uint16_t) * num), VRING_PAGE_SIZE) +
 	(sizeof(VRingUsed) + sizeof(VRingUsedElem) * num);
 }
 
@@ -104,7 +108,7 @@ static void virtqueue_init(VirtQueue *vq
 {
     vq->vring.desc = p;
     vq->vring.avail = p + vq->vring.num * sizeof(VRingDesc);
-    vq->vring.used = (void *)TARGET_PAGE_ALIGN((unsigned long)&vq->vring.avail->ring[vq->vring.num]);
+    vq->vring.used = (void *)ALIGN((unsigned long)&vq->vring.avail->ring[vq->vring.num], VRING_PAGE_SIZE);
 }
 
 static unsigned virtqueue_next_desc(VirtQueue *vq, unsigned int i)
@@ -241,7 +245,7 @@ static void virtio_ioport_write(void *op
 	vdev->features = val;
 	break;
     case VIRTIO_PCI_QUEUE_PFN:
-	pa = (ram_addr_t)val << TARGET_PAGE_BITS;
+	pa = (ram_addr_t)val << VIRTIO_PFN_SHIFT;
 	vdev->vq[vdev->queue_sel].pfn = val;
 	if (pa == 0) {
             virtio_reset(vdev);
@@ -519,7 +523,7 @@ void virtio_load(VirtIODevice *vdev, QEM
 	    size_t size;
 	    target_phys_addr_t pa;
 
-	    pa = (ram_addr_t)vdev->vq[i].pfn << TARGET_PAGE_BITS;
+	    pa = (ram_addr_t)vdev->vq[i].pfn << VIRTIO_PFN_SHIFT;
 	    size = virtqueue_size(vdev->vq[i].vring.num);
 	    virtqueue_init(&vdev->vq[i], virtio_map_gpa(pa, size));
 	}
diff --git a/qemu/target-i386/cpu.h b/qemu/target-i386/cpu.h
--- a/qemu/target-i386/cpu.h
+++ b/qemu/target-i386/cpu.h
@@ -751,6 +751,8 @@ static inline int cpu_get_time_fast(void
 
 #define TARGET_PAGE_BITS 12
 
+#define VIRTIO_PFN_SHIFT 12
+
 #define CPUState CPUX86State
 #define cpu_init cpu_x86_init
 #define cpu_exec cpu_x86_exec
diff --git a/qemu/target-ia64/cpu.h b/qemu/target-ia64/cpu.h
--- a/qemu/target-ia64/cpu.h
+++ b/qemu/target-ia64/cpu.h
@@ -30,6 +30,8 @@
 #define TARGET_LONG_BITS 64
 
 #define TARGET_PAGE_BITS 16
+
+#define VIRTIO_PFN_SHIFT 16
 
 #define ELF_MACHINE	EM_IA_64
 
diff --git a/qemu/target-ppc/cpu.h b/qemu/target-ppc/cpu.h
--- a/qemu/target-ppc/cpu.h
+++ b/qemu/target-ppc/cpu.h
@@ -54,6 +54,8 @@
 #endif /* defined(TARGET_PPCEMB) */
 
 #endif /* defined (TARGET_PPC64) */
+
+#define VIRTIO_PFN_SHIFT 10
 
 #include "cpu-defs.h"