Messages in this thread | | | Subject | Re: [PATCH v2 22/24] vdpa_sim: fix endian-ness of config space | From | Jason Wang <> | Date | Wed, 5 Aug 2020 14:21:07 +0800 |
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On 2020/8/4 上午5:00, Michael S. Tsirkin wrote: > VDPA sim accesses config space as native endian - this is > wrong since it's a modern device and actually uses LE. > > It only supports modern guests so we could punt and > just force LE, but let's use the full virtio APIs since people > tend to copy/paste code, and this is not data path anyway. > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > drivers/vdpa/vdpa_sim/vdpa_sim.c | 31 ++++++++++++++++++++++++++----- > 1 file changed, 26 insertions(+), 5 deletions(-) > > diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c > index a9bc5e0fb353..fa05e065ff69 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) > @@ -306,7 +324,6 @@ static const struct vdpa_config_ops vdpasim_net_config_ops; > > static struct vdpasim *vdpasim_create(void) > { > - struct virtio_net_config *config; > struct vdpasim *vdpasim; > struct device *dev; > int ret = -ENOMEM; > @@ -331,10 +348,7 @@ static struct vdpasim *vdpasim_create(void) > if (!vdpasim->buffer) > goto err_iommu; > > - config = &vdpasim->config; > - config->mtu = 1500; > - config->status = VIRTIO_NET_S_LINK_UP; > - eth_random_addr(config->mac); > + eth_random_addr(vdpasim->config.mac); > > vringh_set_iotlb(&vdpasim->vqs[0].vring, vdpasim->iommu); > vringh_set_iotlb(&vdpasim->vqs[1].vring, vdpasim->iommu); > @@ -448,6 +462,7 @@ static u64 vdpasim_get_features(struct vdpa_device *vdpa) > static int vdpasim_set_features(struct vdpa_device *vdpa, u64 features) > { > struct vdpasim *vdpasim = vdpa_to_sim(vdpa); > + struct virtio_net_config *config = &vdpasim->config; > > /* DMA mapping must be done by driver */ > if (!(features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) > @@ -455,6 +470,12 @@ static int vdpasim_set_features(struct vdpa_device *vdpa, u64 features) > > vdpasim->features = features & vdpasim_features; > > + /* We only know whether guest is using the legacy interface here, so > + * that's the earliest we can set config fields. > + */
We check whether or not ACCESS_PLATFORM is set before which is probably a hint that only modern device is supported. So I wonder just force LE and fail if VERSION_1 is not set is better?
Thanks
> + > + config->mtu = cpu_to_vdpasim16(vdpasim, 1500); > + config->status = cpu_to_vdpasim16(vdpasim, VIRTIO_NET_S_LINK_UP); > return 0; > } >
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