On 10.04.2011, at 21:25, Aurelien Jarno wrote: > On Mon, Apr 04, 2011 at 04:32:10PM +0200, Alexander Graf wrote: >> The feature bitmap in the s390 virtio machine is little endian. To >> address for that, we need to bswap the values after reading them out. >> >> Signed-off-by: Alexander Graf <ag...@suse.de> >> --- >> hw/s390-virtio-bus.c | 4 ++-- >> 1 files changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/hw/s390-virtio-bus.c b/hw/s390-virtio-bus.c >> index 58af164..60e0135 100644 >> --- a/hw/s390-virtio-bus.c >> +++ b/hw/s390-virtio-bus.c >> @@ -223,7 +223,7 @@ void s390_virtio_device_sync(VirtIOS390Device *dev) >> cur_offs += num_vq * VIRTIO_VQCONFIG_LEN; >> >> /* Sync feature bitmap */ >> - stl_phys(cur_offs, dev->host_features); >> + stl_phys(cur_offs, bswap32(dev->host_features)); > > Is bswap32 correct here for both big and little endian guests? I don't > really understand the reason why a bswap is needed here, especially > given that AFAIK this code was already used when using KVM.
This is target specific code. The s390-virtio-bus is s390 specific. And yes, the code was also broken with KVM. That's how I first found it actually. Alex
