On Thu, Oct 10, 2019 at 07:54:07PM +0000, Omer Shpigelman wrote: > The is_vmalloc_addr checks are for user pointers and for memory which was > allocated by the driver with vmalloc_user.
This does not make any sense whatsoever. vmalloc_user returns a kernel address, it just does a GFP_USER instead of GFP_KERNEL allocation, which is just accounting differences. > > > Mapping vmalloc memory is needed for Gaudi ASIC. > > > > How does that ASIC pass in the vmalloc memory? I don't fully understand > > the code, but it seems like the addresses are fed from ioctl, which means > > they only come from userspace. > > The user pointers are indeed fed from ioctl for DMA purpose, but as I wrote > above the vmalloc memory is allocated by the driver with vmalloc_user which > will be mmapped later on in order to create a shared buffer between the > driver and the userspace process. Again, you can't pass pointers obtained from vmalloc* to userspace. You can map the underlying pages into user pagetables, but is_vmalloc_addr won't know that. I think you guys need to read up on virtual memory 101 first and then come back and actually explain what you are trying to do.
