From: Auger Eric <eric.auger@redhat.com>
To: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>,
will.deacon@arm.com
Cc: mark.rutland@arm.com, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
robh+dt@kernel.org, robin.murphy@arm.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 8/8] iommu/arm-smmu-v3: Add support for PCI PASID
Date: Mon, 8 Jul 2019 09:58:16 +0200 [thread overview]
Message-ID: <b0e3d9a9-6085-b393-1982-3dd95bf5d100@redhat.com> (raw)
In-Reply-To: <20190610184714.6786-9-jean-philippe.brucker@arm.com>
Hi Jean,
On 6/10/19 8:47 PM, Jean-Philippe Brucker wrote:
> Enable PASID for PCI devices that support it. Since the SSID tables are
> allocated by arm_smmu_attach_dev(), PASID has to be enabled early enough.
> arm_smmu_dev_feature_enable() would be too late, since by that time the
> main DMA domain has already been attached. Do it in add_device() instead.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
> ---
> drivers/iommu/arm-smmu-v3.c | 51 ++++++++++++++++++++++++++++++++++++-
> 1 file changed, 50 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index 972bfb80f964..a8a516d9ff10 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -2197,6 +2197,49 @@ static void arm_smmu_disable_ats(struct arm_smmu_master *master)
> master->ats_enabled = false;
> }
>
> +static int arm_smmu_enable_pasid(struct arm_smmu_master *master)
> +{
> + int ret;
> + int features;
> + int num_pasids;
> + struct pci_dev *pdev;
> +
> + if (!dev_is_pci(master->dev))
> + return -ENOSYS;
> +
> + pdev = to_pci_dev(master->dev);
> +
> + features = pci_pasid_features(pdev);
> + if (features < 0)
> + return -ENOSYS;
> +
> + num_pasids = pci_max_pasids(pdev);
> + if (num_pasids <= 0)
> + return -ENOSYS;
> +
> + ret = pci_enable_pasid(pdev, features);
> + if (!ret)
> + master->ssid_bits = min_t(u8, ilog2(num_pasids),
> + master->smmu->ssid_bits);
I don't really get why this setting is conditional to the success of
pci_enabled_pasid and not num_pasids > 0.
If it fails the ssid_bits is set to min(smmu->ssid_bits,
fwspec->num_pasid_bits) anyway.
> + return ret;
> +}
> +
> +static void arm_smmu_disable_pasid(struct arm_smmu_master *master)
> +{
> + struct pci_dev *pdev;
> +
> + if (!dev_is_pci(master->dev))
> + return;
> +
> + pdev = to_pci_dev(master->dev);
> +
> + if (!pdev->pasid_enabled)
> + return;
> +
> + pci_disable_pasid(pdev);
> + master->ssid_bits = 0;
in case of a platform device you leave the ssid_bits to a value != 0. Is
that what you want?
> +}
> +
> static void arm_smmu_detach_dev(struct arm_smmu_master *master)
> {
> unsigned long flags;
> @@ -2413,6 +2456,9 @@ static int arm_smmu_add_device(struct device *dev)
>
> master->ssid_bits = min(smmu->ssid_bits, fwspec->num_pasid_bits);
>
> + /* Note that PASID must be enabled before, and disabled after ATS */
> + arm_smmu_enable_pasid(master);
In case the call fails, don't you want to handle the error and reset the
ssid_bits?
> +
> /*
> * If the SMMU doesn't support 2-stage CD, limit the linear
> * tables to a reasonable number of contexts, let's say
> @@ -2423,7 +2469,7 @@ static int arm_smmu_add_device(struct device *dev)
>
> ret = iommu_device_link(&smmu->iommu, dev);
> if (ret)
> - goto err_free_master;
> + goto err_disable_pasid;
>
> group = iommu_group_get_for_dev(dev);
> if (IS_ERR(group)) {
> @@ -2436,6 +2482,8 @@ static int arm_smmu_add_device(struct device *dev)
>
> err_unlink:
> iommu_device_unlink(&smmu->iommu, dev);
> +err_disable_pasid:
> + arm_smmu_disable_pasid(master);
> err_free_master:
> kfree(master);
> fwspec->iommu_priv = NULL;
> @@ -2456,6 +2504,7 @@ static void arm_smmu_remove_device(struct device *dev)
> arm_smmu_detach_dev(master);
> iommu_group_remove_device(dev);
> iommu_device_unlink(&smmu->iommu, dev);
> + arm_smmu_disable_pasid(master);
> kfree(master);
> iommu_fwspec_free(dev);
> }
>
Thanks
Eric
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iommu@lists.linux-foundation.org
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next prev parent reply other threads:[~2019-07-08 8:07 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-10 18:47 [PATCH 0/8] iommu: Add auxiliary domain and PASID support to Arm SMMUv3 Jean-Philippe Brucker
2019-06-10 18:47 ` [PATCH 1/8] iommu: Add I/O ASID allocator Jean-Philippe Brucker
2019-06-11 9:36 ` Jonathan Cameron
2019-06-11 14:35 ` Jean-Philippe Brucker
2019-06-11 18:13 ` Jacob Pan
2019-06-18 14:22 ` Jean-Philippe Brucker
2019-06-18 17:05 ` Jacob Pan
2019-06-19 14:26 ` Jean-Philippe Brucker
2019-06-11 12:26 ` Jacob Pan
2019-06-11 14:37 ` Jean-Philippe Brucker
2019-06-11 17:10 ` Jacob Pan
2019-06-12 11:30 ` Jean-Philippe Brucker
2019-06-10 18:47 ` [PATCH 2/8] dt-bindings: document PASID property for IOMMU masters Jean-Philippe Brucker
2019-07-08 7:58 ` Auger Eric
2019-06-10 18:47 ` [PATCH 3/8] iommu/arm-smmu-v3: Support platform SSID Jean-Philippe Brucker
2019-06-11 9:42 ` Jonathan Cameron
2019-06-11 14:35 ` Jean-Philippe Brucker
2019-06-18 18:08 ` Will Deacon
2019-06-19 11:53 ` Jean-Philippe Brucker
2019-07-08 7:58 ` Auger Eric
2019-09-19 14:51 ` Jean-Philippe Brucker
2019-06-10 18:47 ` [PATCH 4/8] iommu/arm-smmu-v3: Add support for Substream IDs Jean-Philippe Brucker
2019-06-11 10:19 ` Jonathan Cameron
2019-06-11 14:35 ` Jean-Philippe Brucker
2019-06-26 18:00 ` Will Deacon
2019-07-04 9:33 ` Jean-Philippe Brucker
2019-09-19 14:57 ` Jean-Philippe Brucker
2019-07-08 15:31 ` Auger Eric
2019-09-19 15:01 ` Jean-Philippe Brucker
2019-06-10 18:47 ` [PATCH 5/8] iommu/arm-smmu-v3: Add second level of context descriptor table Jean-Philippe Brucker
2019-06-11 10:24 ` Jonathan Cameron
2019-07-08 15:13 ` Auger Eric
2019-09-19 15:05 ` Jean-Philippe Brucker
2019-06-10 18:47 ` [PATCH 6/8] iommu/arm-smmu-v3: Support auxiliary domains Jean-Philippe Brucker
2019-06-26 17:59 ` Will Deacon
2019-07-05 16:29 ` Jean-Philippe Brucker
2019-09-19 15:06 ` Jean-Philippe Brucker
2019-06-10 18:47 ` [PATCH 7/8] iommu/arm-smmu-v3: Improve add_device() error handling Jean-Philippe Brucker
2019-07-08 7:58 ` Auger Eric
2019-06-10 18:47 ` [PATCH 8/8] iommu/arm-smmu-v3: Add support for PCI PASID Jean-Philippe Brucker
2019-06-11 10:45 ` Jonathan Cameron
2019-06-11 14:35 ` Jean-Philippe Brucker
2019-07-08 7:58 ` Auger Eric [this message]
2019-09-19 15:10 ` Jean-Philippe Brucker
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