From: Lu Baolu <baolu.lu@linux.intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: baolu.lu@linux.intel.com, Joerg Roedel <joro@8bytes.org>,
Alex Williamson <alex.williamson@redhat.com>,
Robin Murphy <robin.murphy@arm.com>,
Christoph Hellwig <hch@infradead.org>,
Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Will Deacon <will@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
rafael@kernel.org, Diana Craciun <diana.craciun@oss.nxp.com>,
Cornelia Huck <cohuck@redhat.com>,
Eric Auger <eric.auger@redhat.com>, Liu Yi L <yi.l.liu@intel.com>,
Jacob jun Pan <jacob.jun.pan@intel.com>,
Chaitanya Kulkarni <kch@nvidia.com>,
Stuart Yoder <stuyoder@gmail.com>,
Laurentiu Tudor <laurentiu.tudor@nxp.com>,
Thierry Reding <thierry.reding@gmail.com>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
Jonathan Hunter <jonathanh@nvidia.com>,
Li Yang <leoyang.li@nxp.com>, Dmitry Osipenko <digetx@gmail.com>,
iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 1/8] iommu: Add iommu_group_replace_domain()
Date: Fri, 7 Jan 2022 08:26:50 +0800 [thread overview]
Message-ID: <58e2d0d2-649a-a3f5-e8ae-9cbf2719015f@linux.intel.com> (raw)
In-Reply-To: <20220106170608.GI2328285@nvidia.com>
On 1/7/22 1:06 AM, Jason Gunthorpe wrote:
> On Thu, Jan 06, 2022 at 10:20:46AM +0800, Lu Baolu wrote:
>> Expose an interface to replace the domain of an iommu group for frameworks
>> like vfio which claims the ownership of the whole iommu group.
>>
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>> include/linux/iommu.h | 10 ++++++++++
>> drivers/iommu/iommu.c | 37 +++++++++++++++++++++++++++++++++++++
>> 2 files changed, 47 insertions(+)
>>
>> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
>> index 408a6d2b3034..66ebce3d1e11 100644
>> +++ b/include/linux/iommu.h
>> @@ -677,6 +677,9 @@ void iommu_device_unuse_dma_api(struct device *dev);
>> int iommu_group_set_dma_owner(struct iommu_group *group, void *owner);
>> void iommu_group_release_dma_owner(struct iommu_group *group);
>> bool iommu_group_dma_owner_claimed(struct iommu_group *group);
>> +int iommu_group_replace_domain(struct iommu_group *group,
>> + struct iommu_domain *old,
>> + struct iommu_domain *new);
>>
>> #else /* CONFIG_IOMMU_API */
>>
>> @@ -1090,6 +1093,13 @@ static inline bool iommu_group_dma_owner_claimed(struct iommu_group *group)
>> {
>> return false;
>> }
>> +
>> +static inline int
>> +iommu_group_replace_domain(struct iommu_group *group, struct iommu_domain *old,
>> + struct iommu_domain *new)
>> +{
>> + return -ENODEV;
>> +}
>> #endif /* CONFIG_IOMMU_API */
>>
>> /**
>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>> index 72a95dea688e..ab8ab95969f5 100644
>> +++ b/drivers/iommu/iommu.c
>> @@ -3431,3 +3431,40 @@ bool iommu_group_dma_owner_claimed(struct iommu_group *group)
>> return user;
>> }
>> EXPORT_SYMBOL_GPL(iommu_group_dma_owner_claimed);
>> +
>> +/**
>> + * iommu_group_replace_domain() - Replace group's domain
>> + * @group: The group.
>> + * @old: The previous attached domain. NULL for none.
>> + * @new: The new domain about to be attached.
>> + *
>> + * This is to support backward compatibility for vfio which manages the dma
>> + * ownership in iommu_group level.
>
> This should mention it can only be used with iommu_group_set_dma_owner()
Sure.
>
>> + if (old)
>> + __iommu_detach_group(old, group);
>> +
>> + if (new) {
>> + ret = __iommu_attach_group(new, group);
>> + if (ret && old)
>> + __iommu_attach_group(old, group);
>> + }
>
> The sketchy error unwind here gives me some pause for sure. Maybe we
> should define that on error this leaves the domain as NULL
>
> Complicates vfio a tiny bit to cope with this failure but seems
> cleaner than leaving it indeterminate.
Fair enough.
>
> Jason
>
Best regards,
baolu
next prev parent reply other threads:[~2022-01-07 0:27 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-06 2:20 [PATCH v1 0/8] Scrap iommu_attach/detach_group() interfaces Lu Baolu
2022-01-06 2:20 ` [PATCH v1 1/8] iommu: Add iommu_group_replace_domain() Lu Baolu
2022-01-06 17:06 ` Jason Gunthorpe
2022-01-07 0:26 ` Lu Baolu [this message]
2022-02-14 12:09 ` Robin Murphy
2022-02-14 12:45 ` Jason Gunthorpe
2022-02-14 14:10 ` Robin Murphy
2022-02-14 14:56 ` Jason Gunthorpe
2022-02-14 16:38 ` Robin Murphy
2022-02-14 17:25 ` Jason Gunthorpe
2022-01-06 2:20 ` [PATCH v1 2/8] vfio/type1: Use iommu_group_replace_domain() Lu Baolu
2022-01-06 2:20 ` [PATCH v1 3/8] iommu: Extend iommu_at[de]tach_device() for multi-device groups Lu Baolu
2022-01-06 17:22 ` Jason Gunthorpe
2022-01-07 1:14 ` Lu Baolu
2022-01-07 1:19 ` Jason Gunthorpe
2022-02-14 11:39 ` Joerg Roedel
2022-02-14 13:03 ` Jason Gunthorpe
2022-02-14 14:39 ` Joerg Roedel
2022-02-14 15:18 ` Robin Murphy
2022-02-14 15:46 ` Jason Gunthorpe
2022-02-15 8:58 ` Joerg Roedel
2022-02-15 13:47 ` Jason Gunthorpe
2022-02-16 6:28 ` Lu Baolu
2022-02-16 13:54 ` Jason Gunthorpe
2022-01-06 2:20 ` [PATCH v1 4/8] drm/tegra: Use iommu_attach/detatch_device() Lu Baolu
2022-01-06 2:20 ` [PATCH v1 5/8] iommu/amd: Use iommu_attach/detach_device() Lu Baolu
2022-01-06 14:33 ` Jason Gunthorpe
2022-01-07 0:23 ` Lu Baolu
2022-02-14 11:27 ` Joerg Roedel
2022-02-14 13:15 ` Jason Gunthorpe
2022-02-14 13:40 ` Joerg Roedel
2022-02-14 14:02 ` Jason Gunthorpe
2022-02-14 14:23 ` Joerg Roedel
2022-02-14 15:00 ` Jason Gunthorpe
2022-02-15 9:11 ` Joerg Roedel
2022-02-15 13:02 ` Robin Murphy
2022-02-15 14:37 ` Jason Gunthorpe
2022-01-06 2:20 ` [PATCH v1 6/8] gpu/host1x: " Lu Baolu
2022-01-06 15:35 ` Jason Gunthorpe
2022-01-07 0:35 ` Lu Baolu
2022-01-07 0:48 ` Jason Gunthorpe
2022-01-07 1:19 ` Lu Baolu
2022-01-06 2:20 ` [PATCH v1 7/8] media: staging: media: tegra-vde: " Lu Baolu
2022-01-06 2:20 ` [PATCH v1 8/8] iommu: Remove iommu_attach/detach_group() Lu Baolu
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