Commit a4e8473b authored by Yeoreum Yun's avatar Yeoreum Yun Committed by Sudeep Holla
Browse files

firmware: arm_ffa: Remove vm_id argument in ffa_rxtx_unmap() 



According to the FF-A specification (DEN0077, v1.1, §13.7), when
FFA_RXTX_UNMAP is invoked from any instance other than non-secure
physical, the w1 register must be zero (MBZ). If a non-zero value is
supplied in this context, the SPMC must return FFA_INVALID_PARAMETER.

The Arm FF-A driver operates exclusively as a guest or non-secure
physical instance where the partition ID is always zero and is not
invoked from a hypervisor context where w1 carries a VM ID. In this
execution model, the partition ID observed by the driver is always zero,
and passing a VM ID is unnecessary and potentially invalid.

Remove the vm_id parameter from ffa_rxtx_unmap() and ensure that the
SMC call is issued with w1 implicitly zeroed, as required by the
specification. This prevents invalid parameter errors and aligns the
implementation with the defined FF-A ABI behavior.

Fixes: 3bbfe987 ("firmware: arm_ffa: Add initial Arm FFA driver support")
Signed-off-by: default avatarYeoreum Yun <yeoreum.yun@arm.com>
Message-Id: <20260304120953.847671-1-yeoreum.yun@arm.com>
Signed-off-by: default avatarSudeep Holla <sudeep.holla@kernel.org>
parent 6de23f81

drivers/firmware/arm_ffa/driver.c

+4 −4
Original line number Diff line number Diff line
@@ -205,12 +205,12 @@ static int ffa_rxtx_map(phys_addr_t tx_buf, phys_addr_t rx_buf, u32 pg_cnt) 
	return 0;

}



static int ffa_rxtx_unmap(u16 vm_id)

static int ffa_rxtx_unmap(void)

{

	ffa_value_t ret;



	invoke_ffa_fn((ffa_value_t){

		      .a0 = FFA_RXTX_UNMAP, .a1 = PACK_TARGET_INFO(vm_id, 0),

		      .a0 = FFA_RXTX_UNMAP,

		      }, &ret);



	if (ret.a0 == FFA_ERROR)
@@ -2097,7 +2097,7 @@ static int __init ffa_init(void) 


	pr_err("failed to setup partitions\n");

	ffa_notifications_cleanup();

	ffa_rxtx_unmap(drv_info->vm_id);

	ffa_rxtx_unmap();

free_pages:

	if (drv_info->tx_buffer)

		free_pages_exact(drv_info->tx_buffer, rxtx_bufsz);
@@ -2112,7 +2112,7 @@ static void __exit ffa_exit(void) 
{

	ffa_notifications_cleanup();

	ffa_partitions_cleanup();

	ffa_rxtx_unmap(drv_info->vm_id);

	ffa_rxtx_unmap();

	free_pages_exact(drv_info->tx_buffer, drv_info->rxtx_bufsz);

	free_pages_exact(drv_info->rx_buffer, drv_info->rxtx_bufsz);

	kfree(drv_info);