Re: [PATCH v5 1/3] PCI: dwc: Fix msg_atu_index assignment

Hans Zhang
2026-01-28T06:08:55Z

On 1/27/2026 11:10 PM, Niklas Cassel wrote:
> When dw_pcie_iatu_setup() configures outbound address translation for both
> type PCIE_ATU_TYPE_MEM and PCIE_ATU_TYPE_IO, the iATU index to use is
> incremented before calling dw_pcie_prog_outbound_atu().
>
> However, for msg_atu_index the index is not incremented before use,
> causing the iATU index to be the same as the last configured iATU index,
> which means that it will incorrectly use the same iATU index that is
> already in use, breaking outbound address translation.
>
> In total there are three problems with this code:
> -It assigns msg_atu_index the same index that was used for the last
> outbound address translation window, rather than incrementing the index
> before assignment.
> -The index should only be incremented (and msg_atu_index assigned) if the
> use_atu_msg feature is actually requested/in use (pp->use_atu_msg is set).
> -If the use_atu_msg feature is requested/in use, and there are no outbound
> iATUs available, the code should return an error, as otherwise when this
> this feature is used, it will use an iATU index that is out of bounds.
>
> Fixes: e1a4ec1a9520 ("PCI: dwc: Add generic MSG TLP support for sending PME_Turn_Off when system suspend")
> Cc: stable@vger.kernel.org
> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
> Signed-off-by: Niklas Cassel <cassel@kernel.org>

Reviewed-by: Hans Zhang <zhanghuabing@ecosda.com>

> ---
> drivers/pci/controller/dwc/pcie-designware-host.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index b3d6a474fd16..d7f57d77bdf5 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -982,7 +982,14 @@ static int dw_pcie_iatu_setup(struct dw_pcie_rp *pp)
> dev_warn(pci->dev, "Ranges exceed outbound iATU size (%d)\n",
> pci->num_ob_windows);
>
> - pp->msg_atu_index = i;
> + if (pp->use_atu_msg) {
> + if (pci->num_ob_windows > ++i) {
> + pp->msg_atu_index = i;
> + } else {
> + dev_err(pci->dev, "Cannot add outbound window for MSG TLP\n");
> + return -ENOMEM;
> + }
> + }
>
> i = 0;
> resource_list_for_each_entry(entry, &pp->bridge->dma_ranges) {