Re: [PATCH RFC don't apply] vdpa_sim: endian-ness for config space

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




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@xxxxxxxxxx>


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);

_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization




[Index of Archives]     [KVM Development]     [Libvirt Development]     [Libvirt Users]     [CentOS Virtualization]     [Netdev]     [Ethernet Bridging]     [Linux Wireless]     [Kernel Newbies]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]

  Powered by Linux