Index: block-raw-posix.c
===================================================================
--- block-raw-posix.c	(Revision 4215)
+++ block-raw-posix.c	(Arbeitskopie)
@@ -77,6 +77,7 @@
 typedef struct BDRVRawState {
     int fd;
     int type;
+    int flags;
     unsigned int lseek_err_cnt;
 #if defined(__linux__)
     /* linux floppy specific */
@@ -95,6 +96,7 @@
     BDRVRawState *s = bs->opaque;
     int fd, open_flags, ret;
 
+    s->flags = flags;
     s->lseek_err_cnt = 0;
 
     open_flags = O_BINARY;
@@ -141,7 +143,11 @@
 #endif
 */
 
-static int raw_pread(BlockDriverState *bs, int64_t offset,
+/* 
+ * offset and count are in bytes, but must be multiples of 512 (for files 
+ * opened with O_DIRECT). buf must be aligned to 512 bytes.
+ */
+static int raw_pread_aligned(BlockDriverState *bs, int64_t offset,
                      uint8_t *buf, int count)
 {
     BDRVRawState *s = bs->opaque;
@@ -194,7 +200,11 @@
     return ret;
 }
 
-static int raw_pwrite(BlockDriverState *bs, int64_t offset,
+/* 
+ * offset and count are in bytes, but must be multiples of 512 (for files 
+ * opened with O_DIRECT). buf must be aligned to 512 bytes.
+ */
+static int raw_pwrite_aligned(BlockDriverState *bs, int64_t offset,
                       const uint8_t *buf, int count)
 {
     BDRVRawState *s = bs->opaque;
@@ -230,6 +240,92 @@
     return ret;
 }
 
+
+#ifdef O_DIRECT
+/* 
+ * offset and count are in bytes and possibly not aligned. For files opened 
+ * with O_DIRECT, necessary alignments are ensured before calling 
+ * raw_pread_aligned to do the actual read.
+ */
+static int raw_pread(BlockDriverState *bs, int64_t offset,
+                     uint8_t *buf, int count)
+{
+    BDRVRawState *s = bs->opaque;
+
+    if (unlikely((s->flags & BDRV_O_DIRECT) &&
+            (offset % 512 != 0 || (uintptr_t) buf % 512))) {
+
+        uint8_t* aligned_buf;
+        int64_t aligned_offs = offset & ~511;
+        int aligned_count = (count + offset - aligned_offs + 511) & ~511;
+        int ret;
+
+        aligned_buf = qemu_memalign(512, 512 * aligned_count);
+        ret = raw_pread_aligned(bs, aligned_offs, aligned_buf, aligned_count);
+
+        if (ret > count)
+            ret = count;
+        if (ret > 0)
+            memcpy(buf, aligned_buf + (offset - aligned_offs), ret);
+
+        qemu_free(aligned_buf);
+        return ret;
+
+    } else {
+        return raw_pread_aligned(bs, offset, buf, count);
+    }
+}
+
+/* 
+ * offset and count are in bytes and possibly not aligned. For files opened 
+ * with O_DIRECT, necessary alignments are ensured before calling 
+ * raw_pwrite_aligned to do the actual write.
+ */
+static int raw_pwrite(BlockDriverState *bs, int64_t offset,
+                      const uint8_t *buf, int count)
+{
+    BDRVRawState *s = bs->opaque;
+
+    if (unlikely((s->flags & BDRV_O_DIRECT) &&
+            (offset % 512 != 0 || (uintptr_t) buf % 512))) {
+
+        uint8_t* aligned_buf;
+        int64_t aligned_offs = offset & ~511;
+        int aligned_count = (count + offset - aligned_offs + 511) & ~511;
+        int ret;
+
+        aligned_buf = qemu_memalign(512, 512 * aligned_count);
+
+        /* Read in the first block if needed */
+        if (offset - aligned_offs != 0)
+            raw_pread_aligned(bs, aligned_offs, aligned_buf, 512);
+
+        /* Read in the last block if needed */
+        if ((aligned_count > 512) && ((offset + count) % 512 != 0))
+            raw_pread_aligned(bs,
+                aligned_offs + aligned_count - 512,
+                aligned_buf + aligned_count - 512,
+                512);
+
+        memcpy(aligned_buf + (offset - aligned_offs), buf, count);
+        ret = raw_pwrite_aligned(bs, aligned_offs, aligned_buf, aligned_count);
+
+        if (ret > count)
+            ret = count;
+
+        qemu_free(aligned_buf);
+        return ret;
+    } else {
+        return raw_pwrite_aligned(bs, offset, buf, count);
+    }
+}
+
+#else
+#define raw_pread raw_pread_aligned
+#define raw_pwrite raw_pwrite_aligned
+#endif
+
+
 /***********************************************************/
 /* Unix AIO using POSIX AIO */
 
Index: Makefile
===================================================================
--- Makefile	(Revision 4215)
+++ Makefile	(Arbeitskopie)
@@ -34,7 +34,7 @@
 #######################################################################
 # BLOCK_OBJS is code used by both qemu system emulation and qemu-img
 
-BLOCK_OBJS=cutils.o
+BLOCK_OBJS=cutils.o osdep.o
 BLOCK_OBJS+=block-cow.o block-qcow.o aes.o block-vmdk.o block-cloop.o
 BLOCK_OBJS+=block-dmg.o block-bochs.o block-vpc.o block-vvfat.o
 BLOCK_OBJS+=block-qcow2.o block-parallels.o