Linux-ACPI Archive on lore.kernel.org
 help / color / Atom feed
From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: joro@8bytes.org, will@kernel.org, lorenzo.pieralisi@arm.com,
	robh+dt@kernel.org, guohanjun@huawei.com, sudeep.holla@arm.com,
	rjw@rjwysocki.net, lenb@kernel.org, robin.murphy@arm.com,
	eric.auger@redhat.com, iommu@lists.linux-foundation.org,
	devicetree@vger.kernel.org, linux-acpi@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-accelerators@lists.ozlabs.org, baolu.lu@linux.intel.com,
	jacob.jun.pan@linux.intel.com, kevin.tian@intel.com,
	vdumpa@nvidia.com, zhangfei.gao@linaro.org,
	shameerali.kolothum.thodi@huawei.com, vivek.gautam@arm.com
Subject: Re: [PATCH v11 10/10] iommu/arm-smmu-v3: Add stall support for platform devices
Date: Mon, 25 Jan 2021 16:46:22 +0100
Message-ID: <YA7nzllIPBahYKCw@myrica> (raw)
In-Reply-To: <20210125135009.00003ca3@Huawei.com>

On Mon, Jan 25, 2021 at 01:50:09PM +0000, Jonathan Cameron wrote:
> > +static int arm_smmu_master_sva_enable_iopf(struct arm_smmu_master *master)
> > +{
> > +	int ret;
> > +	struct device *dev = master->dev;
> > +
> > +	/*
> > +	 * Drivers for devices supporting PRI or stall should enable IOPF first.
> > +	 * Others have device-specific fault handlers and don't need IOPF.
> > +	 */
> > +	if (!arm_smmu_master_iopf_supported(master))
> 
> So if we have master->iopf_enabled and this happens. Then I'm not totally sure
> what prevents the disable below running its cleanup on stuff that was never
> configured.

Since arm_smmu_dev_enable_feature() checks that the feature is supported,
iopf_enabled can only be true if arm_smmu_master_iopf_supported() is true.

What's missing is checking that drivers don't disable IOPF while SVA is
enabled - or else the disable below can leak. Another thing I broke in v10 :/

Thanks,
Jean

> 
> > +		return 0;
> > +
> > +	if (!master->iopf_enabled)
> > +		return -EINVAL;
> > +
> > +	ret = iopf_queue_add_device(master->smmu->evtq.iopf, dev);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = iommu_register_device_fault_handler(dev, iommu_queue_iopf, dev);
> > +	if (ret) {
> > +		iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
> > +		return ret;
> > +	}
> > +	return 0;
> > +}
> > +
> > +static void arm_smmu_master_sva_disable_iopf(struct arm_smmu_master *master)
> > +{
> > +	struct device *dev = master->dev;
> > +
> > +	if (!master->iopf_enabled)
> > +		return;
> 
> As above, I think you need a sanity check on
> 
> !arm_smmu_master_iopf_supported(master) before clearing the following.
> 
> I may well be missing something that stops us getting here though.
> 
> Alternative is probably to sanity check iopf_enabled = true is supported
> before letting a driver set it.
> 
> 
> > +
> > +	iommu_unregister_device_fault_handler(dev);
> > +	iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
> > +}

      reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-25 11:06 [PATCH v11 00/10] iommu: I/O page faults for SMMUv3 Jean-Philippe Brucker
2021-01-25 11:06 ` [PATCH v11 01/10] iommu: Fix comment for struct iommu_fwspec Jean-Philippe Brucker
2021-01-25 11:06 ` [PATCH v11 02/10] iommu/arm-smmu-v3: Use device properties for pasid-num-bits Jean-Philippe Brucker
2021-01-25 11:06 ` [PATCH v11 03/10] iommu: Separate IOMMU_DEV_FEAT_IOPF from IOMMU_DEV_FEAT_SVA Jean-Philippe Brucker
2021-01-25 11:06 ` [PATCH v11 04/10] iommu/vt-d: Support IOMMU_DEV_FEAT_IOPF Jean-Philippe Brucker
2021-01-25 11:06 ` [PATCH v11 05/10] uacce: Enable IOMMU_DEV_FEAT_IOPF Jean-Philippe Brucker
2021-01-25 11:06 ` [PATCH v11 06/10] iommu: Add a page fault handler Jean-Philippe Brucker
2021-01-25 11:06 ` [PATCH v11 07/10] iommu/arm-smmu-v3: Maintain a SID->device structure Jean-Philippe Brucker
2021-01-25 11:06 ` [PATCH v11 08/10] dt-bindings: document stall property for IOMMU masters Jean-Philippe Brucker
2021-01-25 11:06 ` [PATCH v11 09/10] ACPI/IORT: Enable stall support for platform devices Jean-Philippe Brucker
2021-01-25 11:06 ` [PATCH v11 10/10] iommu/arm-smmu-v3: Add " Jean-Philippe Brucker
2021-01-25 13:50   ` Jonathan Cameron
2021-01-25 15:46     ` Jean-Philippe Brucker [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YA7nzllIPBahYKCw@myrica \
    --to=jean-philippe@linaro.org \
    --cc=Jonathan.Cameron@huawei.com \
    --cc=baolu.lu@linux.intel.com \
    --cc=devicetree@vger.kernel.org \
    --cc=eric.auger@redhat.com \
    --cc=guohanjun@huawei.com \
    --cc=iommu@lists.linux-foundation.org \
    --cc=jacob.jun.pan@linux.intel.com \
    --cc=joro@8bytes.org \
    --cc=kevin.tian@intel.com \
    --cc=lenb@kernel.org \
    --cc=linux-accelerators@lists.ozlabs.org \
    --cc=linux-acpi@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=lorenzo.pieralisi@arm.com \
    --cc=rjw@rjwysocki.net \
    --cc=robh+dt@kernel.org \
    --cc=robin.murphy@arm.com \
    --cc=shameerali.kolothum.thodi@huawei.com \
    --cc=sudeep.holla@arm.com \
    --cc=vdumpa@nvidia.com \
    --cc=vivek.gautam@arm.com \
    --cc=will@kernel.org \
    --cc=zhangfei.gao@linaro.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-ACPI Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-acpi/0 linux-acpi/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-acpi linux-acpi/ https://lore.kernel.org/linux-acpi \
		linux-acpi@vger.kernel.org
	public-inbox-index linux-acpi

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-acpi


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git