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Date:   Fri, 20 Oct 2023 14:02:45 +0100
From:   Giovanni Cabiddu <giovanni.cabiddu@intel.com>
To:     Herbert Xu <herbert@gondor.apana.org.au>
CC:     Damian Muszynski <damian.muszynski@intel.com>,
        <linux-crypto@vger.kernel.org>, <qat-linux@intel.com>
Subject: Re: [PATCH 00/11] crypto: qat - add rate limiting feature to qat_4xxx
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On Fri, Oct 20, 2023 at 01:27:00PM +0800, Herbert Xu wrote:
> On Wed, Oct 11, 2023 at 02:14:58PM +0200, Damian Muszynski wrote:
> > This set introduces the rate limiting feature to the Intel QAT accelerator.
> > The Rate Limiting allows control of the rate of the requests that can be
> > submitted on a ring pair (RP). This allows sharing a QAT device among
> > multiple users while ensuring a guaranteed throughput.
> 
> This does not sound like something that should sit in a driver.
To clarify, this is enabling *hardware* rate limiting.

The driver is not doing any active control flow on the jobs submitted to
the accelerator. Instead, it provides a mechanism that allows system
admins to set policies that are then programmed to the device.
Such policies allow to restrict the flow or provide a committed rate on
selected ring pairs.

In brief, the role of the driver is parameter checking and device
configuration based on inputs.

> Could we implement this in crypto_engine instead?
I do not see how this can be implemented in the crypto_engine as rate
limiting functionalities in QAT are applicable not only to requests
submitted through the crypto API but also to requests submitted from a
user space application through qatlib and from a guest virtual machine.

Regards,

-- 
Giovanni