Re: [PATCH v2 5/5] iommu/arm-smmu: Convert to domain_alloc_paging()

From: Will Deacon <will@kernel.org>
To: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Robin Murphy <robin.murphy@arm.com>,
	Jason Gunthorpe <jgg@nvidia.com>,
	iommu@lists.linux.dev, joro@8bytes.org,
	linux-arm-kernel@lists.infradead.org, nicolinc@nvidia.com,
	linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH v2 5/5] iommu/arm-smmu: Convert to domain_alloc_paging()
Date: Tue, 13 Feb 2024 11:16:23 +0000	[thread overview]
Message-ID: <20240213111623.GA28517@willie-the-truck> (raw)
In-Reply-To: <CAA8EJpqtUnGXMPQO4F0JXQDv0oJKFYjuhf4hSBe2tY1ebWFjRA@mail.gmail.com>

On Tue, Feb 13, 2024 at 12:55:38PM +0200, Dmitry Baryshkov wrote:
> On Tue, 13 Feb 2024 at 12:20, Robin Murphy <robin.murphy@arm.com> wrote:
> > On 2024-02-13 7:51 am, Dmitry Baryshkov wrote:
> > > On Sat, 10 Feb 2024 at 00:23, Jason Gunthorpe <jgg@nvidia.com> wrote:
> > >> And then we may get a clue from the backtraces it generates. I only
> > >> saw one iommu group reported in your log so I'd expect one trace?
> > >
> > > I added dev_info + mdelays() around the arm_smmu_init_domain_context()
> > > and I can see that it crashes within that function.
> >
> > Yeah, this is totally broken. We can't just call the unmodified
> > arm_smmu_init_domain_context() at domain allocation because half of what
> > it's doing belongs to the attach operation. We should not be allocating
> > context banks, IRQs, etc. for a not-yet-attached domain, and we
> > certainly shouldn't be touching hardware there outside of RPM.
> 
> Should I send a revert?

If reverting the patch fixes the issue for you, then yes please!

Hopefully you can help Jason test a reworked verson for the future, as
it's evident that Tegra doesn't tickle the power management side of things
in the same way.

Will

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