From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: [PATCH RFC don't apply] vdpa_sim: endian-ness for config space Date: Wed, 15 Jul 2020 09:58:08 -0400 Message-ID: <20200715135540.22832-1-mst@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: Jason Wang , virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org 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 --- 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 #include #include +#include #include #include #include @@ -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); -- MST