On Tue, Mar 14, 2023 at 02:05:50AM +0000, Parav Pandit wrote: > > > From: Si-Wei Liu <[email protected]> > > Sent: Monday, March 13, 2023 6:19 PM > > > Actually there's no such burden or requirement to maintain backward > > compatibility for the default 'vdpa dev add' behavior if dedicated > > device_features is not specified. Historically the default vdpa creation on > > mlx5 > > ever got changed from single queue to 8 queue pairs when VIRTIO_NET_F_MQ > > feature was first introduced to mlx5_vdpa, then the default switched back > > to 1 > > data queue pair again when max_vqp attribute was added to the vdpa tool. > > Essentially, every addition of new feature to mlx5_vdpa, e.g. CTRL_VQ, > > CTRL_VLAN, and et al, effectively changed the default "vdpa dev add" > > behavior > > not just only once: the backward compatibility guarantee is simply just not > > there and ever. > This requires that every change in the device attributes will change the > behavior for vdpa dev add. > The OR operation of the user supplied feature bits with device defaults > feature bit doesn’t look good to me. > It brings uncertain behavior. > > The right behavior should be, if user supplied the feature bits, it should > supply all desired bits.
I think u mean all that device also supports. > If user doesn’t supply feature bits, use the device defaults. > But not to mix both feature bits. Can't say I understand what this means. What does "both" mean here? -- MST _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
