Messages in this thread | | | Subject | Re: [PATCH RFC don't apply] vdpa_sim: endian-ness for config space | From | Jason Wang <> | Date | Wed, 15 Jul 2020 22:02:32 +0800 |
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On 2020/7/15 下午9:58, Michael S. Tsirkin wrote: > VDPA sim stores config space as native endian, but that > is wrong: modern guests expect LE. > I coded up the following to fix it up, but it is wrong too: > vdpasim_create is called before guest features are known. > > So what should we do? New ioctl to specify the interface used? > More ideas? > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Can we do the endian conversion in set_config/get_config()?
Thanks
> > > --- > drivers/vdpa/vdpa_sim/vdpa_sim.c | 22 ++++++++++++++++++++-- > 1 file changed, 20 insertions(+), 2 deletions(-) > > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c > index a9bc5e0fb353..cc754ae0ec15 100644 > --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c > +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c > @@ -24,6 +24,7 @@ > #include <linux/etherdevice.h> > #include <linux/vringh.h> > #include <linux/vdpa.h> > +#include <linux/virtio_byteorder.h> > #include <linux/vhost_iotlb.h> > #include <uapi/linux/virtio_config.h> > #include <uapi/linux/virtio_net.h> > @@ -72,6 +73,23 @@ struct vdpasim { > u64 features; > }; > > +/* TODO: cross-endian support */ > +static inline bool vdpasim_is_little_endian(struct vdpasim *vdpasim) > +{ > + return virtio_legacy_is_little_endian() || > + (vdpasim->features & (1ULL << VIRTIO_F_VERSION_1)); > +} > + > +static inline u16 vdpasim16_to_cpu(struct vdpasim *vdpasim, __virtio16 val) > +{ > + return __virtio16_to_cpu(vdpasim_is_little_endian(vdpasim), val); > +} > + > +static inline __virtio16 cpu_to_vdpasim16(struct vdpasim *vdpasim, u16 val) > +{ > + return __cpu_to_virtio16(vdpasim_is_little_endian(vdpasim), val); > +} > + > static struct vdpasim *vdpasim_dev; > > static struct vdpasim *vdpa_to_sim(struct vdpa_device *vdpa) > @@ -332,8 +350,8 @@ static struct vdpasim *vdpasim_create(void) > goto err_iommu; > > config = &vdpasim->config; > - config->mtu = 1500; > - config->status = VIRTIO_NET_S_LINK_UP; > + config->mtu = cpu_to_vdpasim16(vdpasim, 1500); > + config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP); > eth_random_addr(config->mac); > > vringh_set_iotlb(&vdpasim->vqs[0].vring, vdpasim->iommu);
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