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From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Rob Clark <robdclark@chromium.org>,
	linux-arm-msm@vger.kernel.org, iommu@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org, Sibi Sankar <sibis@codeaurora.org>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 6/8] iommu/arm-smmu: Add impl hook for inherit boot mappings
Date: Sat, 12 Sep 2020 22:25:59 -0500	[thread overview]
Message-ID: <20200913032559.GT3715@yoga> (raw)
In-Reply-To: <0bfcc8f7-d054-616b-834b-319461b1ecb9@arm.com>

On Fri 11 Sep 12:13 CDT 2020, Robin Murphy wrote:

> On 2020-09-04 16:55, Bjorn Andersson wrote:
> > Add a new operation to allow platform implementations to inherit any
> > stream mappings from the boot loader.
> 
> Is there a reason we need an explicit step for this? The aim of the
> cfg_probe hook is that the SMMU software state should all be set up by then,
> and you can mess about with it however you like before arm_smmu_reset()
> actually commits anything to hardware. I would have thought you could
> permanently steal a context bank, configure it as your bypass hole, read out
> the previous SME configuration and tweak smmu->smrs and smmu->s2crs
> appropriately all together "invisibly" at that point.

I did this because as of 6a79a5a3842b ("iommu/arm-smmu: Call
configuration impl hook before consuming features") we no longer have
setup pgsize_bitmap as we hit cfg_probe, which means that I need to
replicate this logic to set up the iommu_domain.

If I avoid setting up an iommu_domain for the identity context, as you
request in patch 8, this shouldn't be needed anymore.

> If that can't work, I'm very curious as to what I've overlooked.
> 

I believe that will work, I will rework the patches and try it out.

Thanks,
Bjorn

> Robin.
> 
> > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > ---
> > 
> > Changes since v2:
> > - New patch/interface
> > 
> >   drivers/iommu/arm/arm-smmu/arm-smmu.c | 11 ++++++-----
> >   drivers/iommu/arm/arm-smmu/arm-smmu.h |  6 ++++++
> >   2 files changed, 12 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > index eb5c6ca5c138..4c4d302cd747 100644
> > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > @@ -85,11 +85,6 @@ static inline void arm_smmu_rpm_put(struct arm_smmu_device *smmu)
> >   		pm_runtime_put_autosuspend(smmu->dev);
> >   }
> > -static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
> > -{
> > -	return container_of(dom, struct arm_smmu_domain, domain);
> > -}
> > -
> >   static struct platform_driver arm_smmu_driver;
> >   static struct iommu_ops arm_smmu_ops;
> > @@ -2188,6 +2183,12 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
> >   	if (err)
> >   		return err;
> > +	if (smmu->impl->inherit_mappings) {
> > +		err = smmu->impl->inherit_mappings(smmu);
> > +		if (err)
> > +			return err;
> > +	}
> > +
> >   	if (smmu->version == ARM_SMMU_V2) {
> >   		if (smmu->num_context_banks > smmu->num_context_irqs) {
> >   			dev_err(dev,
> > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h
> > index 235d9a3a6ab6..f58164976e74 100644
> > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
> > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
> > @@ -378,6 +378,11 @@ struct arm_smmu_domain {
> >   	struct iommu_domain		domain;
> >   };
> > +static inline struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
> > +{
> > +	return container_of(dom, struct arm_smmu_domain, domain);
> > +}
> > +
> >   struct arm_smmu_master_cfg {
> >   	struct arm_smmu_device		*smmu;
> >   	s16				smendx[];
> > @@ -442,6 +447,7 @@ struct arm_smmu_impl {
> >   	int (*alloc_context_bank)(struct arm_smmu_domain *smmu_domain,
> >   				  struct arm_smmu_device *smmu,
> >   				  struct device *dev, int start);
> > +	int (*inherit_mappings)(struct arm_smmu_device *smmu);
> >   };
> >   #define INVALID_SMENDX			-1
> > 
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  reply	other threads:[~2020-09-13  3:26 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-04 15:55 [PATCH v3 0/8] iommu/arm-smmu: Support maintaining bootloader mappings Bjorn Andersson
2020-09-04 15:55 ` [PATCH v3 1/8] iommu/arm-smmu: Refactor context bank allocation Bjorn Andersson
2020-09-08 18:42   ` Jordan Crouse
2020-09-08 18:46     ` Jordan Crouse
2020-09-11  8:18   ` Sai Prakash Ranjan
2020-09-04 15:55 ` [PATCH v3 2/8] iommu/arm-smmu: Delay modifying domain during init Bjorn Andersson
2020-09-11  8:20   ` Sai Prakash Ranjan
2020-09-04 15:55 ` [PATCH v3 3/8] iommu/arm-smmu: Consult context bank allocator for identify domains Bjorn Andersson
2020-09-11  8:21   ` Sai Prakash Ranjan
2020-09-11  8:24   ` Sai Prakash Ranjan
2020-09-04 15:55 ` [PATCH v3 4/8] iommu/arm-smmu-qcom: Emulate bypass by using context banks Bjorn Andersson
2020-09-11  8:25   ` Sai Prakash Ranjan
2020-09-04 15:55 ` [PATCH v3 5/8] iommu/arm-smmu-qcom: Consistently initialize stream mappings Bjorn Andersson
2020-09-11  8:26   ` Sai Prakash Ranjan
2020-09-04 15:55 ` [PATCH v3 6/8] iommu/arm-smmu: Add impl hook for inherit boot mappings Bjorn Andersson
2020-09-11  8:27   ` Sai Prakash Ranjan
2020-09-11 17:13   ` Robin Murphy
2020-09-13  3:25     ` Bjorn Andersson [this message]
2020-09-21 21:08       ` Will Deacon
2020-09-24 15:55         ` Bjorn Andersson
2020-10-12  7:31         ` Bjorn Andersson
2020-10-13 16:47           ` Robin Murphy
2020-09-04 15:55 ` [PATCH v3 7/8] iommu/arm-smmu: Provide helper for allocating identity domain Bjorn Andersson
2020-09-11  8:28   ` Sai Prakash Ranjan
2020-09-04 15:55 ` [PATCH v3 8/8] iommu/arm-smmu-qcom: Setup identity domain for boot mappings Bjorn Andersson
2020-09-11  8:29   ` Sai Prakash Ranjan
2020-09-11 17:29   ` Robin Murphy
2020-09-05 22:27 ` [PATCH v3 0/8] iommu/arm-smmu: Support maintaining bootloader mappings Rob Clark
2020-09-09 14:46 ` Laurentiu Tudor
2020-09-10 22:56 ` John Stultz
2020-09-11  8:16 ` Sai Prakash Ranjan
2020-09-11 16:10 ` Amit Pundir
2020-09-16 10:09 ` Laurentiu Tudor

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