On Wed, 2023-11-01 at 11:20 +0530, Jaskaran Singh wrote: > > External email : Please do not click links or open attachments until > you have verified the sender or the content. > On 10/20/2023 3:20 PM, Yong Wu (吴勇) wrote: > > On Thu, 2023-10-19 at 10:16 +0530, Vijayanand Jitta wrote: > >> > >> Instead of having a vendor specific binding for cma area, How > about > >> retrieving > >> > > > https://lore.kernel.org/lkml/1594948208-4739-1-git-send-email-hayashi.kunihiko@xxxxxxxxxxxxx/ > >> ? > >> dma_heap_add_cma can just associate cma region and create a heap. > So, > >> we can reuse cma heap > >> code for allocation instead of replicating that code here. > >> > > > > Thanks for the reference. I guess we can't use it. There are two > > reasons: > > > > a) The secure heap driver is a pure software driver and we have no > > device for it, therefore we cannot call dma_heap_add_cma. > > > > Hi Yong, > > We're considering using struct cma as the function argument to > dma_heap_add_cma() rather than struct device. Would this help > resolve the problem of usage with dma_heap_add_cma()? Yes. If we use "struct cma", I guess it works. > > > b) The CMA area here is dynamic for SVP. Normally this CMA can be > used > > in the kernel. In the SVP case we use cma_alloc to get it and pass > the > > entire CMA physical start address and size into TEE to protect the > CMA > > region. The original CMA heap cannot help with the TEE part. > > > > Referring the conversation at > https://lore.kernel.org/lkml/7a2995de23c24ef22c071c6976c02b97e9b50126.camel@xxxxxxxxxxxx/ > ; > > since we're considering abstracting secure mem ops, would it make > sense > to use the default CMA heap ops (cma_heap_ops), allocate buffers from > it > and secure each allocated buffer? Then it looks you also need tee operation like tee_client_open_session and tee_client_invoke_func, right? It seems we also need change a bit for "cma_heap_allocate" to allow cma support operations from secure heap. I will send a v2 to move the discussion forward. The v2 is based on our case, It won't include the cma part. > > Thanks, > Jaskaran. > > > Thanks. > > > >> Thanks, > >> Vijay > >> > >> > >> >
