On 2021/3/1 5:34 上午, Michael S. Tsirkin wrote:
On Wed, Feb 24, 2021 at 10:24:41AM -0800, Si-Wei Liu wrote:
Detecting it isn't enough though, we will need a new ioctl to notify
the kernel that it's a legacy guest. Ugh :(
Well, although I think adding an ioctl is doable, may I know what the use
case there will be for kernel to leverage such info directly? Is there a
case QEMU can't do with dedicate ioctls later if there's indeed
differentiation (legacy v.s. modern) needed?
BTW a good API could be
#define VHOST_SET_ENDIAN _IOW(VHOST_VIRTIO, ?, int)
#define VHOST_GET_ENDIAN _IOW(VHOST_VIRTIO, ?, int)
we did it per vring but maybe that was a mistake ...
Actually, I wonder whether it's good time to just not support legacy
driver for vDPA. Consider:
1) It's definition is no-normative
2) A lot of budren of codes
So qemu can still present the legacy device since the config space or
other stuffs that is presented by vhost-vDPA is not expected to be
accessed by guest directly. Qemu can do the endian conversion when
necessary in this case?
Thanks
_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
