Using tightVNC, the colors are messed up when viewing a PV guest running
on a 3.2 hypervisor from a client system with a 16 bit deep display.
virt-manager --> viewer works OK.
Standalone virt-viewer and other VNC clients have bad colors.  

This problem is new with Xen 3.2 and the qemu xenfb code.

As a short term fix I added a second macro in tools/ioemu/hw/xenfb.c to
munge the colors from 32 bit  to 16 bit based on an algorithm used by
RealVNC.  Patch I used is attached, not suggesting it be merged.

Is anybody else seeing this problem?

By the way, while looking at the original macro I think the last shift
for blue should of used BRS instead if GRS.  ( Changing that did not
make the colors better. )

#define BLT(SRC_T,DST_T,RLS,GLS,BLS,RRS,GRS,BRS,RM,GM,BM)               \
    for (line = y ; line < h ; line++) {                                \
        SRC_T *src = (SRC_T *)(xenfb->pixels                            \
                               + (line * xenfb->row_stride)             \
                               + (x * xenfb->depth / 8));               \
        DST_T *dst = (DST_T
*)(xenfb->ds->data                                 \
                               + (line *
xenfb->ds->linesize)                  \
                               + (x * xenfb->ds->depth /
8));                  \
        int col;                                                        \
        for (col = x ; col < w ; col++) {                               \
            *dst = (((*src >> RRS) & RM) << RLS) |                      \
                (((*src >> GRS) & GM) << GLS) |                         \
-                (((*src >> GRS) & BM) << BLS);                          \
+               (((*src >> BRS) & BM) << BLS);                          \
            src++;                                                      \
            dst++;                                                      \
        }                                                               \
    }