From: Lu Baolu <baolu.lu@linux.intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>, David Airlie <airlied@linux.ie>,
Robin Murphy <robin.murphy@arm.com>,
iommu@lists.linux-foundation.org,
Jacob jun Pan <jacob.jun.pan@intel.com>,
Christoph Hellwig <hch@infradead.org>,
Alex Williamson <alex.williamson@redhat.com>,
Thierry Reding <thierry.reding@gmail.com>,
Ben Skeggs <bskeggs@redhat.com>, Daniel Vetter <daniel@ffwll.ch>,
Jonathan Hunter <jonathanh@nvidia.com>,
Will Deacon <will@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 6/7] iommu: Use right way to retrieve iommu_ops
Date: Tue, 25 Jan 2022 11:18:01 +0800 [thread overview]
Message-ID: <e4493dac-07bf-7ee3-5bea-a159fd37a2dd@linux.intel.com> (raw)
In-Reply-To: <20220124173650.GF966497@nvidia.com>
On 1/25/22 1:36 AM, Jason Gunthorpe wrote:
> On Mon, Jan 24, 2022 at 03:11:01PM +0800, Lu Baolu wrote:
>> The common iommu_ops is hooked to both device and domain. When a helper
>> has both device and domain pointer, the way to get the iommu_ops looks
>> messy in iommu core. This sorts out the way to get iommu_ops. The device
>> related helpers go through device pointer, while the domain related ones
>> go through domain pointer.
>>
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>> include/linux/iommu.h | 8 ++++++++
>> drivers/iommu/iommu.c | 25 ++++++++++++++-----------
>> 2 files changed, 22 insertions(+), 11 deletions(-)
>>
>> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
>> index aa5486243892..111b3e9c79bb 100644
>> +++ b/include/linux/iommu.h
>> @@ -385,6 +385,14 @@ static inline void iommu_iotlb_gather_init(struct iommu_iotlb_gather *gather)
>> };
>> }
>>
>> +static inline const struct iommu_ops *dev_iommu_ops_get(struct device *dev)
>> +{
>> + if (dev && dev->iommu && dev->iommu->iommu_dev)
>> + return dev->iommu->iommu_dev->ops;
>> +
>> + return NULL;
>
> What is the purpose of this helper?
Get the iommu_ops from a device pointer. Just want to avoid duplicate
code in various functions.
>
>> + const struct iommu_ops *ops = dev_iommu_ops_get(dev);
>> struct iommu_domain *domain = group->default_domain;
>> struct iommu_resv_region *entry;
>> struct list_head mappings;
>> @@ -785,8 +786,8 @@ static int iommu_create_device_direct_mappings(struct iommu_group *group,
>> dma_addr_t start, end, addr;
>> size_t map_size = 0;
>>
>> - if (domain->ops->apply_resv_region)
>> - domain->ops->apply_resv_region(dev, domain, entry);
>> + if (ops->apply_resv_region)
>> + ops->apply_resv_region(dev, domain, entry);
>
> Here we call it and don't check for NULL? So why did we check the
> interior pointers in the helper?
Yes. Should check.
>
>> @@ -831,8 +832,10 @@ static int iommu_create_device_direct_mappings(struct iommu_group *group,
>> static bool iommu_is_attach_deferred(struct iommu_domain *domain,
>> struct device *dev)
>> {
>> - if (domain->ops->is_attach_deferred)
>> - return domain->ops->is_attach_deferred(domain, dev);
>> + const struct iommu_ops *ops = dev_iommu_ops_get(dev);
>> +
>> + if (ops->is_attach_deferred)
>> + return ops->is_attach_deferred(domain, dev);
>
> Same here, at least return false if ops is null..
Yes.
>
>> @@ -1251,10 +1254,10 @@ int iommu_page_response(struct device *dev,
>> struct iommu_fault_event *evt;
>> struct iommu_fault_page_request *prm;
>> struct dev_iommu *param = dev->iommu;
>> + const struct iommu_ops *ops = dev_iommu_ops_get(dev);
>> bool has_pasid = msg->flags & IOMMU_PAGE_RESP_PASID_VALID;
>> - struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
>>
>> - if (!domain || !domain->ops->page_response)
>> + if (!ops || !ops->page_response)
>> return -ENODEV;
>>
>> if (!param || !param->fault_param)
>> @@ -1295,7 +1298,7 @@ int iommu_page_response(struct device *dev,
>> msg->pasid = 0;
>> }
>>
>> - ret = domain->ops->page_response(dev, evt, msg);
>> + ret = ops->page_response(dev, evt, msg);
>> list_del(&evt->list);
>> kfree(evt);
>> break;
>
> Feels weird that page_response is not connected to a domain, the fault
> originated from a domain after all. I would say this op should be
> moved to the domain and the caller should provide the a pointer to the
> domain that originated the fault.
>
> Ideally since only some domain's will be configured to handle faults
> at all - domains that can't do this should have a NULL page_response
> op, even if other domains created by the same device driver could
> handle page_response..
>
>> @@ -1758,10 +1761,10 @@ static int __iommu_group_dma_attach(struct iommu_group *group)
>>
>> static int iommu_group_do_probe_finalize(struct device *dev, void *data)
>> {
>> - struct iommu_domain *domain = data;
>> + const struct iommu_ops *ops = dev_iommu_ops_get(dev);
>>
>> - if (domain->ops->probe_finalize)
>> - domain->ops->probe_finalize(dev);
>> + if (ops->probe_finalize)
>> + ops->probe_finalize(dev);
>
> This is an oddball one too, it is finishing setting up the default
> domain for a device? Several drivers seem to recover the default
> domain in their implementations..
In order to avoid default domain type (DMA or IDENDITY) conflict among
devices in a same iommu_group, the probe process is divided into two
phases, one for determining the default domain type and the other for
allocating the default domain and attaching it to the device.
ops->probe_finalize() is called to tell the vendor iommu driver that
the device probe is done. Normally the vendor iommu driver could set the
dma ops in this callback.
>
> Jason
>
Best regards,
baolu
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2022-01-25 3:19 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-24 7:10 [PATCH 0/7] iommu cleanup and refactoring Lu Baolu
2022-01-24 7:10 ` [PATCH 1/7] iommu/vt-d: Remove guest pasid related callbacks Lu Baolu
2022-01-24 9:25 ` Christoph Hellwig
2022-01-24 7:10 ` [PATCH 2/7] iommu: Remove guest pasid related interfaces and definitions Lu Baolu
2022-01-24 9:26 ` Christoph Hellwig
2022-01-24 7:10 ` [PATCH 3/7] iommu/vt-d: Remove aux-domain related callbacks Lu Baolu
2022-01-24 9:26 ` Christoph Hellwig
2022-01-24 7:10 ` [PATCH 4/7] iommu: Remove aux-domain related interfaces and iommu_ops Lu Baolu
2022-01-24 9:27 ` Christoph Hellwig
2022-01-24 7:11 ` [PATCH 5/7] drm/nouveau/device: Get right pgsize_bitmap of iommu_domain Lu Baolu
2022-01-24 9:29 ` Christoph Hellwig
2022-01-25 2:59 ` Lu Baolu
2022-01-24 7:11 ` [PATCH 6/7] iommu: Use right way to retrieve iommu_ops Lu Baolu
2022-01-24 9:32 ` Christoph Hellwig
2022-01-25 3:01 ` Lu Baolu
2022-01-24 9:48 ` Tian, Kevin
2022-01-25 3:04 ` Lu Baolu
2022-01-24 17:36 ` Jason Gunthorpe via iommu
2022-01-25 3:18 ` Lu Baolu [this message]
2022-01-25 0:20 ` Robin Murphy
2022-01-25 3:54 ` Lu Baolu
2022-01-24 7:11 ` [PATCH 7/7] iommu: Add iommu_domain::domain_ops Lu Baolu
2022-01-24 9:37 ` Christoph Hellwig
2022-01-24 17:24 ` Jason Gunthorpe via iommu
2022-01-25 4:43 ` Lu Baolu
2022-01-25 4:42 ` Lu Baolu
2022-01-24 9:58 ` Tian, Kevin
2022-01-24 10:16 ` Jean-Philippe Brucker
2022-01-24 16:33 ` Jason Gunthorpe via iommu
2022-01-26 9:41 ` Jean-Philippe Brucker
2022-01-24 17:17 ` Jason Gunthorpe via iommu
2022-01-25 4:59 ` Lu Baolu
2022-01-25 12:37 ` Jason Gunthorpe via iommu
2022-01-24 17:55 ` Jason Gunthorpe via iommu
2022-01-25 5:04 ` Lu Baolu
2022-01-25 0:57 ` Robin Murphy
2022-01-25 6:27 ` Lu Baolu
2022-01-25 14:23 ` Robin Murphy
2022-01-25 15:00 ` Jason Gunthorpe via iommu
2022-01-24 9:46 ` [PATCH 0/7] iommu cleanup and refactoring Tian, Kevin
2022-01-24 17:44 ` Jason Gunthorpe via iommu
2022-01-25 1:11 ` Tian, Kevin
2022-01-25 14:48 ` Robin Murphy
2022-01-25 15:16 ` Jason Gunthorpe via iommu
2022-01-26 1:51 ` Lu Baolu
2022-01-26 13:27 ` Jason Gunthorpe via iommu
2022-01-26 14:00 ` Robin Murphy
2022-02-08 1:32 ` Lu Baolu
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=e4493dac-07bf-7ee3-5bea-a159fd37a2dd@linux.intel.com \
--to=baolu.lu@linux.intel.com \
--cc=airlied@linux.ie \
--cc=alex.williamson@redhat.com \
--cc=ashok.raj@intel.com \
--cc=bskeggs@redhat.com \
--cc=daniel@ffwll.ch \
--cc=hch@infradead.org \
--cc=iommu@lists.linux-foundation.org \
--cc=jacob.jun.pan@intel.com \
--cc=jgg@nvidia.com \
--cc=jonathanh@nvidia.com \
--cc=kevin.tian@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=robin.murphy@arm.com \
--cc=thierry.reding@gmail.com \
--cc=will@kernel.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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).