Re: [RFC PATCH v3 4/7] bus/cdx: add cdx-MSI domain with gic-its domain as parent

Jason Gunthorpe
2022-09-06T17:28:23Z

On Tue, Sep 06, 2022 at 07:17:58PM +0530, Nipun Gupta wrote:

> +static void cdx_msi_write_msg(struct irq_data *irq_data,
> + struct msi_msg *msg)
> +{
> + /*
> + * Do nothing as CDX devices have these pre-populated
> + * in the hardware itself.
> + */
> +}

Huh?

There is no way it can be pre-populated, the addr/data pair,
especially on ARM, is completely under SW control. There is some
commonly used IOVA base in Linux for the ITS page, but no HW should
hardwire that.

Jason