From: Jason Gunthorpe <jgg@nvidia.com>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Joerg Roedel <joro@8bytes.org>,
Christoph Hellwig <hch@infradead.org>,
Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Jean-Philippe Brucker <jean-philippe@linaro.com>,
Dave Jiang <dave.jiang@intel.com>, Vinod Koul <vkoul@kernel.org>,
Eric Auger <eric.auger@redhat.com>, Liu Yi L <yi.l.liu@intel.com>,
Jacob jun Pan <jacob.jun.pan@intel.com>,
Zhangfei Gao <zhangfei.gao@linaro.org>,
Zhu Tony <tony.zhu@intel.com>,
iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
Jean-Philippe Brucker <jean-philippe@linaro.org>
Subject: Re: [PATCH v10 04/12] iommu: Add attach/detach_dev_pasid iommu interface
Date: Sat, 23 Jul 2022 11:11:18 -0300 [thread overview]
Message-ID: <20220723141118.GD79279@nvidia.com> (raw)
In-Reply-To: <20220705050710.2887204-5-baolu.lu@linux.intel.com>
On Tue, Jul 05, 2022 at 01:07:02PM +0800, Lu Baolu wrote:
> Attaching an IOMMU domain to a PASID of a device is a generic operation
> for modern IOMMU drivers which support PASID-granular DMA address
> translation. Currently visible usage scenarios include (but not limited):
>
> - SVA (Shared Virtual Address)
> - kernel DMA with PASID
> - hardware-assist mediated device
>
> This adds a pair of domain ops for this purpose and adds the interfaces
> for device drivers to attach/detach a domain to/from a {device, PASID}.
> Some buses, like PCI, route packets without considering the PASID
> value.
Below the comments touch on ACS, so this is a bit out of date
> +static bool iommu_group_immutable_singleton(struct iommu_group *group,
> + struct device *dev)
> +{
> + int count;
> +
> + mutex_lock(&group->mutex);
> + count = iommu_group_device_count(group);
> + mutex_unlock(&group->mutex);
> +
> + if (count != 1)
> + return false;
> +
> + /*
> + * The PCI device could be considered to be fully isolated if all
> + * devices on the path from the device to the host-PCI bridge are
> + * protected from peer-to-peer DMA by ACS.
> + */
> + if (dev_is_pci(dev))
> + return pci_acs_path_enabled(to_pci_dev(dev), NULL,
> + REQ_ACS_FLAGS);
You might want to explain what condition causes ACS isolated devices
to share a group in the first place..
> +
> + /*
> + * Otherwise, the device came from DT/ACPI, assume it is static and
> + * then singleton can know from the device count in the group.
> + */
> + return true;
> +}
I would be happer if probe was changed to refuse to add a device to a
group if the group's pasid xarray is not empty, as a protective
measure.
> +int iommu_attach_device_pasid(struct iommu_domain *domain, struct device *dev,
> + ioasid_t pasid)
> +{
> + struct iommu_group *group;
> + void *curr;
> + int ret;
> +
> + if (!domain->ops->set_dev_pasid)
> + return -EOPNOTSUPP;
> +
> + group = iommu_group_get(dev);
> + if (!group || !iommu_group_immutable_singleton(group, dev)) {
> + iommu_group_put(group);
> + return -EINVAL;
goto error below
> + }
> +
> + mutex_lock(&group->mutex);
Just hold the group->mutex a few lines above and don't put locking in
iommu_group_immutable_singleton(), it is clearer
> +void iommu_detach_device_pasid(struct iommu_domain *domain, struct device *dev,
> + ioasid_t pasid)
> +{
> + struct iommu_group *group = iommu_group_get(dev);
> +
> + mutex_lock(&group->mutex);
> + domain->ops->block_dev_pasid(domain, dev, pasid);
I still really this OP, it is nonsense to invoke 'block_dev_pasid' on
a domain, it should be on the iommu ops and it should not take in a
domain parameter. This is why I prefer we write it as
domain->ops->set_dev_pasid(group->blocking_domain, dev, pasid);
> + xa_erase(&group->pasid_array, pasid);
It is worth checking that the value returned from xa_erase is domain
and WARN_ON if not, since we are passing domain in..
Jason
next prev parent reply other threads:[~2022-07-23 14:11 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-05 5:06 [PATCH v10 00/12] iommu: SVA and IOPF refactoring Lu Baolu
2022-07-05 5:06 ` [PATCH v10 01/12] iommu: Add max_pasids field in struct iommu_device Lu Baolu
2022-07-23 13:57 ` Jason Gunthorpe
2022-07-31 11:54 ` Yi Liu
2022-07-31 13:33 ` Baolu Lu
2022-07-05 5:07 ` [PATCH v10 02/12] iommu: Add max_pasids field in struct dev_iommu Lu Baolu
2022-07-23 14:02 ` Jason Gunthorpe
2022-07-31 11:55 ` Yi Liu
2022-07-05 5:07 ` [PATCH v10 03/12] iommu: Remove SVM_FLAG_SUPERVISOR_MODE support Lu Baolu
2022-07-31 12:01 ` Yi Liu
2022-07-31 13:39 ` Baolu Lu
2022-07-05 5:07 ` [PATCH v10 04/12] iommu: Add attach/detach_dev_pasid iommu interface Lu Baolu
2022-07-07 1:51 ` Tian, Kevin
2022-07-23 14:11 ` Jason Gunthorpe [this message]
2022-07-24 7:03 ` Baolu Lu
2022-07-25 14:40 ` Jason Gunthorpe
2022-07-26 6:23 ` Baolu Lu
2022-07-26 13:57 ` Jason Gunthorpe
2022-07-27 3:20 ` Tian, Kevin
2022-07-27 11:53 ` Jason Gunthorpe
2022-07-28 3:06 ` Tian, Kevin
2022-07-28 11:59 ` Jason Gunthorpe
2022-07-29 2:49 ` Baolu Lu
2022-07-29 2:56 ` Tian, Kevin
2022-07-29 3:20 ` Baolu Lu
2022-07-29 4:22 ` Tian, Kevin
2022-07-30 6:17 ` Baolu Lu
2022-07-29 2:51 ` Tian, Kevin
2022-07-29 12:22 ` Jason Gunthorpe
2022-07-30 6:23 ` Baolu Lu
2022-07-28 2:44 ` Baolu Lu
2022-07-28 6:27 ` Baolu Lu
2022-08-02 2:19 ` Baolu Lu
2022-08-02 12:37 ` Jason Gunthorpe
2022-08-03 13:07 ` Baolu Lu
2022-08-03 19:03 ` Jason Gunthorpe
2022-08-04 2:03 ` Tian, Kevin
2022-08-04 2:42 ` Baolu Lu
2022-07-24 7:23 ` Baolu Lu
2022-07-24 8:39 ` Baolu Lu
2022-07-24 9:13 ` Baolu Lu
2022-07-25 7:46 ` Tian, Kevin
2022-07-25 10:11 ` Baolu Lu
2022-07-31 12:10 ` Yi Liu
2022-07-05 5:07 ` [PATCH v10 05/12] iommu: Add IOMMU SVA domain support Lu Baolu
2022-07-07 1:52 ` Tian, Kevin
2022-07-07 3:01 ` Baolu Lu
2022-07-23 14:15 ` Jason Gunthorpe
2022-07-31 12:19 ` Yi Liu
2022-07-05 5:07 ` [PATCH v10 06/12] iommu/vt-d: Add " Lu Baolu
2022-07-23 14:16 ` Jason Gunthorpe
2022-07-31 12:20 ` Yi Liu
2022-07-05 5:07 ` [PATCH v10 07/12] arm-smmu-v3/sva: " Lu Baolu
2022-07-23 14:20 ` Jason Gunthorpe
2022-07-24 11:58 ` Baolu Lu
2022-07-05 5:07 ` [PATCH v10 08/12] iommu/sva: Refactoring iommu_sva_bind/unbind_device() Lu Baolu
2022-07-05 17:43 ` Jean-Philippe Brucker
2022-07-07 1:56 ` Tian, Kevin
2022-07-07 3:02 ` Baolu Lu
2022-07-23 14:26 ` Jason Gunthorpe
2022-07-24 13:48 ` Baolu Lu
2022-07-25 7:39 ` Jean-Philippe Brucker
2022-07-25 8:02 ` Tian, Kevin
2022-07-25 8:47 ` Jean-Philippe Brucker
2022-07-25 9:33 ` Baolu Lu
2022-07-25 9:52 ` Jean-Philippe Brucker
2022-07-25 14:46 ` Jason Gunthorpe
2022-07-25 7:50 ` Tian, Kevin
2022-07-25 10:22 ` Baolu Lu
2022-07-25 14:47 ` Jason Gunthorpe
2022-07-26 8:47 ` Baolu Lu
2022-07-31 12:36 ` Yi Liu
2022-07-31 13:45 ` Baolu Lu
2022-07-31 12:55 ` Yi Liu
2022-07-31 13:51 ` Baolu Lu
2022-07-05 5:07 ` [PATCH v10 09/12] iommu: Remove SVA related callbacks from iommu ops Lu Baolu
2022-07-23 14:27 ` Jason Gunthorpe
2022-07-31 12:38 ` Yi Liu
2022-07-05 5:07 ` [PATCH v10 10/12] iommu: Prepare IOMMU domain for IOPF Lu Baolu
2022-07-07 1:58 ` Tian, Kevin
2022-07-23 14:33 ` Jason Gunthorpe
2022-07-24 14:04 ` Baolu Lu
2022-07-25 14:49 ` Jason Gunthorpe
2022-07-31 12:50 ` Yi Liu
2022-07-31 13:47 ` Baolu Lu
2022-07-05 5:07 ` [PATCH v10 11/12] iommu: Per-domain I/O page fault handling Lu Baolu
2022-07-07 2:06 ` Tian, Kevin
2022-07-23 14:34 ` Jason Gunthorpe
2022-07-05 5:07 ` [PATCH v10 12/12] iommu: Rename iommu-sva-lib.{c,h} Lu Baolu
2022-07-23 14:34 ` Jason Gunthorpe
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