From: Jerry Snitselaar <jsnitsel@redhat.com>
To: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
dmaengine@vger.kernel.org
Subject: Re: Question about the recent idxd/iaa changes
Date: Mon, 18 Mar 2024 15:34:35 -0700 [thread overview]
Message-ID: <7rrvqwcvuzvygnbow2wvzolvp5bq5dgaytk24filf3uyz47tv7@dvvj4y6tz6xb> (raw)
In-Reply-To: <f653d44ae2a955b021eea2acb7616321d8e0cff7.camel@linux.intel.com>
On Mon, Mar 18, 2024 at 04:57:52PM -0500, Tom Zanussi wrote:
> Hi Jerry,
>
> On Mon, 2024-03-18 at 13:35 -0700, Jerry Snitselaar wrote:
> > On Mon, Mar 18, 2024 at 01:18:58AM -0700, Jerry Snitselaar wrote:
> > > With adding the support for loading external drivers like iaa,
> > > autoloading, and default configs, systems with IAA that are booted
> > > in
> > > legacy mode get a number of probe failing messages from the user
> > > driver for the iax wqs before it probes with the iaa_crypto
> > > driver. Should the name match check occur prior to checking if user
> > > pasid is enabled in idxd_user_drv_probe? On a GNR system this will
> > > generate over 100 log messages at boot like the following:
> > >
> > > [ 56.885504] user: probe of wq15.0 failed with error -95
> > >
> > > Regards,
> > > Jerry
> > >
> >
> > Hi Tom,
> >
> > A couple more iaa questions I had:
> >
> > - Are you supposed to disable all iax workqueues/devices to
> > reconfigure a workqueue? It seems perfectly happy to let you
> > disable, reconfigure, and enable just one. I know for idxd in
> > general the intent is to be able to disable, configure, and enable
> > workqueues/devices as needed for different users. I'm wondering if
> > that is the case for iaa as well since it talks about unloading and
> > loading iaa_crypto for new configurations.
> >
>
> In general the idea is that you set up your workqueues/devices, which
> registers the iaa-crypto algorithm and makes it available as a plugin
> to e.g. zswap. The register happens on the probe of the first wq,
> subsequent wqs are added after that and rebalance the wq table, so
> yeah, you can also reconfigure wqs in the same way.
>
> But you can't remove and reconfigure everything and re-register the
> algorithm, see below.
>
> >
> > - Is there a reason that iaa_crypto needs to be reloaded beyond the
> > compression algorithm registration? I tried moving the unregister
> > into iaa_crypto_remove with a check that the iaa_devices list is
> > empty, and it seemed to work, but I wasn't sure if there some other
> > reason for it being in iaa_crypto_cleanup_module instead of
> > iaa_crypto_remove similar to the register call in iaa_crypto_probe.
> >
>
> The requirement to only allow the algorithm to be unregistered on
> module unload came from the crypto maintainer during review [1].
>
> Specifically, this part:
>
> 1) Never unregister your crypto algorithms, even after the last
> piece of hardware has been unplugged. The algorithms should only
> be unregistered (if they have been registered through the first
> successful probe call) in the module unload function.
>
> hth,
>
> Tom
>
>
> [1] https://lore.kernel.org/lkml/ZC58JggIXgpJ1tpD@gondor.apana.org.au/
>
>
Thank you for the explanation and information Tom.
Regards,
Jerry
>
>
>
> > Regards,
> > Jerry
> >
>
prev parent reply other threads:[~2024-03-18 22:34 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-18 8:18 Question about the recent idxd/iaa changes Jerry Snitselaar
2024-03-18 20:35 ` Jerry Snitselaar
2024-03-18 21:57 ` Tom Zanussi
2024-03-18 22:34 ` Jerry Snitselaar [this message]
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