From: Alexander Graf <agraf@suse.de>
Date: Tue, 10 Jan 2012 22:33:10 +0000 (+0100)
Subject: virtio: change memcpy to guest reads
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=06dbfc6f8833475065c9cf5fdbdb990dbb4b619b;p=qemu-xen-4.4-testing.git

virtio: change memcpy to guest reads

When accessing the device specific virtio config space, we memcpy
the data into a variable in QEMU. At that point we're basically
pulling host endianness into the game which is a really bad idea.

So instead, let's use the target specific load/store helpers for
memory pointers which fetch things in target endianness. The whole
array is already populated in target endianness anyways
(see virtio-blk).

Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
---

diff --git a/hw/virtio.c b/hw/virtio.c
index 81ecc40b3..74cc038af 100644
--- a/hw/virtio.c
+++ b/hw/virtio.c
@@ -539,7 +539,7 @@ uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr)
     if (addr > (vdev->config_len - sizeof(val)))
         return (uint32_t)-1;
 
-    memcpy(&val, vdev->config + addr, sizeof(val));
+    val = ldub_p(vdev->config + addr);
     return val;
 }
 
@@ -552,7 +552,7 @@ uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr)
     if (addr > (vdev->config_len - sizeof(val)))
         return (uint32_t)-1;
 
-    memcpy(&val, vdev->config + addr, sizeof(val));
+    val = lduw_p(vdev->config + addr);
     return val;
 }
 
@@ -565,7 +565,7 @@ uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr)
     if (addr > (vdev->config_len - sizeof(val)))
         return (uint32_t)-1;
 
-    memcpy(&val, vdev->config + addr, sizeof(val));
+    val = ldl_p(vdev->config + addr);
     return val;
 }
 
@@ -576,7 +576,7 @@ void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data)
     if (addr > (vdev->config_len - sizeof(val)))
         return;
 
-    memcpy(vdev->config + addr, &val, sizeof(val));
+    stb_p(vdev->config + addr, val);
 
     if (vdev->set_config)
         vdev->set_config(vdev, vdev->config);
@@ -589,7 +589,7 @@ void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data)
     if (addr > (vdev->config_len - sizeof(val)))
         return;
 
-    memcpy(vdev->config + addr, &val, sizeof(val));
+    stw_p(vdev->config + addr, val);
 
     if (vdev->set_config)
         vdev->set_config(vdev, vdev->config);
@@ -602,7 +602,7 @@ void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
     if (addr > (vdev->config_len - sizeof(val)))
         return;
 
-    memcpy(vdev->config + addr, &val, sizeof(val));
+    stl_p(vdev->config + addr, val);
 
     if (vdev->set_config)
         vdev->set_config(vdev, vdev->config);