Re: [PATCH v3 6/7] xen/arm: Implement the logic for static shared memory from Xen heap

[Michal Orzel <michal.orzel@xxxxxxx>]

Hi Luca,

On 22/05/2024 09:51, Luca Fancellu wrote:
> 
> 
> This commit implements the logic to have the static shared memory banks
> from the Xen heap instead of having the host physical address passed from
> the user.
> 
> When the host physical address is not supplied, the physical memory is
> taken from the Xen heap using allocate_domheap_memory, the allocation
> needs to occur at the first handled DT node and the allocated banks
> need to be saved somewhere.
> 
> Introduce the 'shm_heap_banks' for that reason, a struct that will hold
> the banks allocated from the heap, its field bank[].shmem_extra will be
> used to point to the bootinfo shared memory banks .shmem_extra space, so
> that there is not further allocation of memory and every bank in
> shm_heap_banks can be safely identified by the shm_id to reconstruct its
> traceability and if it was allocated or not.
> 
> A search into 'shm_heap_banks' will reveal if the banks were allocated
> or not, in case the host address is not passed, and the callback given
> to allocate_domheap_memory will store the banks in the structure and
> map them to the current domain, to do that, some changes to
> acquire_shared_memory_bank are made to let it differentiate if the bank
> is from the heap and if it is, then assign_pages is called for every
> bank.
> 
> When the bank is already allocated, for every bank allocated with the
> corresponding shm_id, handle_shared_mem_bank is called and the mapping
> are done.
> 
> Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>

~Michal