Re: [Qemu-devel] [PATCH] rdma: don't make pages writeable if not requiested

[Jason Gunthorpe]

On Thu, Mar 21, 2013 at 07:42:37PM +0200, Michael S. Tsirkin wrote:

> It doesn't actually, and our app would sometimes write to these pages.
> It simply does not care which version does the remote get in this case
> since we track writes and resend later.

Heh, somehow I thought you might say that :)

A new flag seems like the only way then - maybe:
  IBV_ACCESS_NON_COHERENT - The adaptor and the CPU do not share
     a coherent view of registered memory. Memory writes from the CPU
     after ibv_reg_mr completes may not be reflected in the memory
     viewed by the adaptor.

     Can only be combined with read only access permissions.

Jason