From: Sudeep Holla sudeep.holla@arm.com
commit 111a833dc5cbef3d05b2a796a7e23cb7f6ff2192 upstream.
The transmit buffers allocated by the driver can be used to transmit data by any messages/commands needing the buffer. However, it is not guaranteed to have been zero-ed before every new transmission and hence it will just contain residual value from the previous transmission. There are several reserved fields in the memory descriptors that must be zero(MBZ). The receiver can reject the transmission if any such MBZ fields are non-zero.
While we can set the whole page to zero, it is not optimal as most of the fields get initialised to the value required for the current transmission.
So, just set the reserved/MBZ fields to zero in the memory descriptors explicitly to honour the requirement and keep the receiver happy.
Fixes: cc2195fe536c ("firmware: arm_ffa: Add support for MEM_* interfaces") Reported-by: Marc Bonnici marc.bonnici@arm.com Link: https://lore.kernel.org/r/20230503131252.12585-1-sudeep.holla@arm.com Signed-off-by: Sudeep Holla sudeep.holla@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/firmware/arm_ffa/driver.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/drivers/firmware/arm_ffa/driver.c +++ b/drivers/firmware/arm_ffa/driver.c @@ -420,12 +420,17 @@ ffa_setup_and_transmit(u32 func_id, void ep_mem_access->receiver = args->attrs[idx].receiver; ep_mem_access->attrs = args->attrs[idx].attrs; ep_mem_access->composite_off = COMPOSITE_OFFSET(args->nattrs); + ep_mem_access->flag = 0; + ep_mem_access->reserved = 0; } + mem_region->reserved_0 = 0; + mem_region->reserved_1 = 0; mem_region->ep_count = args->nattrs;
composite = buffer + COMPOSITE_OFFSET(args->nattrs); composite->total_pg_cnt = ffa_get_num_pages_sg(args->sg); composite->addr_range_cnt = num_entries; + composite->reserved = 0;
length = COMPOSITE_CONSTITUENTS_OFFSET(args->nattrs, num_entries); frag_len = COMPOSITE_CONSTITUENTS_OFFSET(args->nattrs, 0); @@ -460,6 +465,7 @@ ffa_setup_and_transmit(u32 func_id, void
constituents->address = sg_phys(args->sg); constituents->pg_cnt = args->sg->length / FFA_PAGE_SIZE; + constituents->reserved = 0; constituents++; frag_len += sizeof(struct ffa_mem_region_addr_range); } while ((args->sg = sg_next(args->sg)));