Thanks for the review. Unfortunately only the first vmbus message take effect and subsequent calls are ignored. I originally implemented using vram helpers but I figured out calling this vmbus message again won't change the vram location.
/me notices there also is user_ctx. What is this?
Not sure, I will try to get in touch with hyper-v folks internally to see if page-flip can be used.
I think that needs a very big comment. Maybe even enforce that with a "vram_gpa_set" boolean in the device structure, and complain if we try to do that twice.
Also I guess congrats to microsoft for defining things like that :- /
I would be kind of surprised if the virtual device doesn't support pageflips. Maybe setting vram_gpa just isn't the correct way to do it. Is there a specification available?
There are a number of microsoft folks in Cc: Anyone willing to comment?
thanks, Gerd
PS: And, yes, in case pageflips really don't work going with shmem helpers + blits is reasonable.