From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Yeoreum Yun <yeoreum.yun@arm.com>,
	Sudeep Holla <sudeep.holla@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.12 378/460] firmware: arm_ffa: Remove vm_id argument in ffa_rxtx_unmap()
Date: Mon, 23 Mar 2026 14:46:14 +0100
Message-ID: <20260323134535.854643512@linuxfoundation.org>
In-Reply-To: <20260323134526.647552166@linuxfoundation.org>
References: <20260323134526.647552166@linuxfoundation.org>
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6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yeoreum Yun <yeoreum.yun@arm.com>

[ Upstream commit a4e8473b775160f3ce978f621cf8dea2c7250433 ]

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: 3bbfe9871005 ("firmware: arm_ffa: Add initial Arm FFA driver support")
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Message-Id: <20260304120953.847671-1-yeoreum.yun@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/firmware/arm_ffa/driver.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index 9516ee870cd25..bec1fbaff7f34 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -206,12 +206,12 @@ 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)
@@ -1832,7 +1832,7 @@ static int __init ffa_init(void)
 
 cleanup_notifs:
 	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);
@@ -1847,7 +1847,7 @@ 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);
-- 
2.51.0