On Tue, Mar 01, 2016 at 04:49:38PM +0000, Andre Przywara wrote: > Currently we deny any VHOST_* functionality if the architecture > supports guests with different endianness than the host. Most of the > time even on those architectures the endianness of guest and host are > the same, though, so we are denying the glory of VHOST needlessly. > Switch from compile time determination to a run time scheme, which > takes the actual endianness of the guest into account. > For this we change the semantics of VIRTIO_ENDIAN_HOST to return the > actual endianness of the host (the endianness of kvmtool at compile > time, really). The actual check in vhost_net now compares this against > the guest endianness. > This enables vhost support on ARM and ARM64. > > Signed-off-by: Andre Przywara <[email protected]> > --- > include/kvm/virtio.h | 9 +++++++-- > virtio/net.c | 2 +- > 2 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/include/kvm/virtio.h b/include/kvm/virtio.h > index 768ee96..66530fd 100644 > --- a/include/kvm/virtio.h > +++ b/include/kvm/virtio.h > @@ -17,10 +17,15 @@ > #define VIRTIO_PCI_O_CONFIG 0 > #define VIRTIO_PCI_O_MSIX 1 > > -#define VIRTIO_ENDIAN_HOST 0 > #define VIRTIO_ENDIAN_LE (1 << 0) > #define VIRTIO_ENDIAN_BE (1 << 1) > > +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ > +#define VIRTIO_ENDIAN_HOST VIRTIO_ENDIAN_LE > +#else > +#define VIRTIO_ENDIAN_HOST VIRTIO_ENDIAN_BE > +#endif
pci.h already uses __BYTE_ORDER and __LITTLE_ENDIAN, so we should at least be consistent here. Will
