Re: [PATCH 2/2] PCI: dwc: ep: Add MSI-X Enable checks before raising MSI-X to the host

[Niklas Cassel]

On Wed, Feb 25, 2026 at 09:53:59PM +0530, Manivannan Sadhasivam wrote:
> PCIe spec r7, sec 7.7.2.2 mandates that a Function should raise MSI-X only
> if the MSI-X Enable bit is set and MSI enable bit is clear.
> 
> Hence, add those checks to be spec compliant.
> 
> Suggested-by: Bjorn Helgaas <helgaas@xxxxxxxxxx>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxxxxxxxx>
> ---
>  drivers/pci/controller/dwc/pcie-designware-ep.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index fcbd648e049e..47bc33346342 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> @@ -1018,6 +1018,15 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>  	if (!ep_func || !ep_func->msix_cap)
>  		return -EINVAL;
>  
> +	/*
> +	 * PCIe spec r7, sec 7.7.2.2 mandates that a Function should raise MSI-X
> +	 * only if the MSI-X Enable bit is set and MSI Enable bit is clear.
> +	 */
> +	if (!dw_pcie_ep_msix_enabled(ep, ep_func, func_no) ||
> +	    (dw_pcie_ep_msix_enabled(ep, ep_func, func_no) &&
> +	     dw_pcie_ep_msi_enabled(ep, ep_func, func_no)))
> +		return -EOPNOTSUPP;

Same comment as patch 1/2.


Kind regards,
Niklas