From: "Tian, Kevin" <kevin.tian@intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: "Alex Williamson (alex.williamson@redhat.com)"
<alex.williamson@redhat.com>, Joerg Roedel <joro@8bytes.org>,
"Jean-Philippe Brucker" <jean-philippe@linaro.org>,
David Gibson <david@gibson.dropbear.id.au>,
Jason Wang <jasowang@redhat.com>,
"parav@mellanox.com" <parav@mellanox.com>,
"Enrico Weigelt, metux IT consult" <lkml@metux.net>,
Paolo Bonzini <pbonzini@redhat.com>,
Shenming Lu <lushenming@huawei.com>,
Eric Auger <eric.auger@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
"Raj, Ashok" <ashok.raj@intel.com>,
"Liu, Yi L" <yi.l.liu@intel.com>, "Wu, Hao" <hao.wu@intel.com>,
"Jiang, Dave" <dave.jiang@intel.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
"Kirti Wankhede" <kwankhede@nvidia.com>,
Robin Murphy <robin.murphy@arm.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"David Woodhouse" <dwmw2@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
"Lu Baolu" <baolu.lu@linux.intel.com>
Subject: RE: Plan for /dev/ioasid RFC v2
Date: Mon, 28 Jun 2021 02:03:56 +0000 [thread overview]
Message-ID: <BN9PR11MB5433DCBE6DE1EC27CFB9D3738C039@BN9PR11MB5433.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20210625143616.GT2371267@nvidia.com>
Hi, Jason,
> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Friday, June 25, 2021 10:36 PM
>
> The only thing that needs to be done to get the 1:1 step is to broadly
> define how the other two cases will work so we don't get into trouble
> and set some way to exclude the problematic cases from even getting to
> iommu_fd in the first place.
>
> For instance if we go ahead and create /dev/vfio/device nodes we could
> do this only if the group was 1:1, otherwise the group cdev has to be
> used, along with its API.
>
I may misunderstand your position in last reply.
The bottom line is that iommu fd uAPI and helper functions should be
device-centric (no group fd carried). This is what this sketch tries to
achieve.
However I'm getting confused on your position on vfio uAPIs.
At some point I feel you are OK to keep vfio group fd:
"For others, I don't think this is *strictly* necessary, we can
probably still get to the device_fd using the group_fd and fit in
/dev/ioasid. It does make the rest of this more readable though."
https://lore.kernel.org/linux-iommu/PH0PR12MB54811863B392C644E5365446DC3E9@PH0PR12MB5481.namprd12.prod.outlook.com/T/#m1b1d2b4d6413e3b32ba972a97c2c6a16bf491796
But you are also obviously against faking group for mdev.
Combining with the last paragraph above, are you actually suggesting
that 1:1 group (including mdev) should use a new device-centric vfio
uAPI (without group fd) while existing group-centric vfio uAPI is only
kept for 1:N group (with slight semantics change in my sketch to match
device-centric iommu fd API)?
If yes, some assumptions in this sketch might be changed. For example,
with /dev/vfio/device node I'm not sure how the user can pass {iommu_fd,
device_cookie} to establish the security context when opening the node
(not via an indirect group ioctl). Then it implies that we may have to allow
the user open a device before it is put into a security context, thus the
safe guard may have to be enabled on mmap() for 1:1 group. This is a
different sequence from the existing group-centric model.
Anyway, appreciate if you can elaborate your thoughts so we can further
think about them.
Thanks
Kevin
WARNING: multiple messages have this Message-ID (diff)
From: "Tian, Kevin" <kevin.tian@intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Jason Wang <jasowang@redhat.com>,
Kirti Wankhede <kwankhede@nvidia.com>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
"Jiang, Dave" <dave.jiang@intel.com>,
"Raj, Ashok" <ashok.raj@intel.com>,
Jonathan Corbet <corbet@lwn.net>,
"parav@mellanox.com" <parav@mellanox.com>,
"Alex Williamson \(alex.williamson@redhat.com\)"
<alex.williamson@redhat.com>,
"Enrico Weigelt, metux IT consult" <lkml@metux.net>,
David Gibson <david@gibson.dropbear.id.au>,
Robin Murphy <robin.murphy@arm.com>,
LKML <linux-kernel@vger.kernel.org>,
Shenming Lu <lushenming@huawei.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
Paolo Bonzini <pbonzini@redhat.com>,
David Woodhouse <dwmw2@infradead.org>
Subject: RE: Plan for /dev/ioasid RFC v2
Date: Mon, 28 Jun 2021 02:03:56 +0000 [thread overview]
Message-ID: <BN9PR11MB5433DCBE6DE1EC27CFB9D3738C039@BN9PR11MB5433.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20210625143616.GT2371267@nvidia.com>
Hi, Jason,
> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Friday, June 25, 2021 10:36 PM
>
> The only thing that needs to be done to get the 1:1 step is to broadly
> define how the other two cases will work so we don't get into trouble
> and set some way to exclude the problematic cases from even getting to
> iommu_fd in the first place.
>
> For instance if we go ahead and create /dev/vfio/device nodes we could
> do this only if the group was 1:1, otherwise the group cdev has to be
> used, along with its API.
>
I may misunderstand your position in last reply.
The bottom line is that iommu fd uAPI and helper functions should be
device-centric (no group fd carried). This is what this sketch tries to
achieve.
However I'm getting confused on your position on vfio uAPIs.
At some point I feel you are OK to keep vfio group fd:
"For others, I don't think this is *strictly* necessary, we can
probably still get to the device_fd using the group_fd and fit in
/dev/ioasid. It does make the rest of this more readable though."
https://lore.kernel.org/linux-iommu/PH0PR12MB54811863B392C644E5365446DC3E9@PH0PR12MB5481.namprd12.prod.outlook.com/T/#m1b1d2b4d6413e3b32ba972a97c2c6a16bf491796
But you are also obviously against faking group for mdev.
Combining with the last paragraph above, are you actually suggesting
that 1:1 group (including mdev) should use a new device-centric vfio
uAPI (without group fd) while existing group-centric vfio uAPI is only
kept for 1:N group (with slight semantics change in my sketch to match
device-centric iommu fd API)?
If yes, some assumptions in this sketch might be changed. For example,
with /dev/vfio/device node I'm not sure how the user can pass {iommu_fd,
device_cookie} to establish the security context when opening the node
(not via an indirect group ioctl). Then it implies that we may have to allow
the user open a device before it is put into a security context, thus the
safe guard may have to be enabled on mmap() for 1:1 group. This is a
different sequence from the existing group-centric model.
Anyway, appreciate if you can elaborate your thoughts so we can further
think about them.
Thanks
Kevin
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2021-06-28 2:04 UTC|newest]
Thread overview: 162+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-07 2:58 Plan for /dev/ioasid RFC v2 Tian, Kevin
2021-06-07 2:58 ` Tian, Kevin
2021-06-09 8:14 ` Eric Auger
2021-06-09 8:14 ` Eric Auger
2021-06-09 9:37 ` Tian, Kevin
2021-06-09 9:37 ` Tian, Kevin
2021-06-09 10:14 ` Eric Auger
2021-06-09 10:14 ` Eric Auger
2021-06-09 9:01 ` Leon Romanovsky
2021-06-09 9:01 ` Leon Romanovsky
2021-06-09 9:43 ` Tian, Kevin
2021-06-09 9:43 ` Tian, Kevin
2021-06-09 12:24 ` Joerg Roedel
2021-06-09 12:24 ` Joerg Roedel
2021-06-09 12:39 ` Jason Gunthorpe
2021-06-09 12:39 ` Jason Gunthorpe
2021-06-09 13:32 ` Joerg Roedel
2021-06-09 13:32 ` Joerg Roedel
2021-06-09 15:00 ` Jason Gunthorpe
2021-06-09 15:00 ` Jason Gunthorpe
2021-06-09 15:51 ` Joerg Roedel
2021-06-09 15:51 ` Joerg Roedel
2021-06-09 16:15 ` Alex Williamson
2021-06-09 16:15 ` Alex Williamson
2021-06-09 16:27 ` Alex Williamson
2021-06-09 16:27 ` Alex Williamson
2021-06-09 18:49 ` Jason Gunthorpe
2021-06-09 18:49 ` Jason Gunthorpe
2021-06-10 15:38 ` Alex Williamson
2021-06-10 15:38 ` Alex Williamson
2021-06-11 0:58 ` Tian, Kevin
2021-06-11 0:58 ` Tian, Kevin
2021-06-11 21:38 ` Alex Williamson
2021-06-11 21:38 ` Alex Williamson
2021-06-14 3:09 ` Tian, Kevin
2021-06-14 3:09 ` Tian, Kevin
2021-06-14 3:22 ` Alex Williamson
2021-06-14 3:22 ` Alex Williamson
2021-06-15 1:05 ` Tian, Kevin
2021-06-15 1:05 ` Tian, Kevin
2021-06-14 13:38 ` Jason Gunthorpe
2021-06-14 13:38 ` Jason Gunthorpe
2021-06-15 1:21 ` Tian, Kevin
2021-06-15 1:21 ` Tian, Kevin
2021-06-15 16:56 ` Alex Williamson
2021-06-15 16:56 ` Alex Williamson
2021-06-16 6:53 ` Tian, Kevin
2021-06-16 6:53 ` Tian, Kevin
2021-06-24 4:50 ` David Gibson
2021-06-24 4:50 ` David Gibson
2021-06-11 16:45 ` Jason Gunthorpe
2021-06-11 16:45 ` Jason Gunthorpe
2021-06-11 19:38 ` Alex Williamson
2021-06-11 19:38 ` Alex Williamson
2021-06-12 1:28 ` Jason Gunthorpe
2021-06-12 1:28 ` Jason Gunthorpe
2021-06-12 16:57 ` Alex Williamson
2021-06-12 16:57 ` Alex Williamson
2021-06-14 14:07 ` Jason Gunthorpe
2021-06-14 14:07 ` Jason Gunthorpe
2021-06-14 16:28 ` Alex Williamson
2021-06-14 16:28 ` Alex Williamson
2021-06-14 19:40 ` Jason Gunthorpe
2021-06-14 19:40 ` Jason Gunthorpe
2021-06-15 2:31 ` Tian, Kevin
2021-06-15 2:31 ` Tian, Kevin
2021-06-15 16:12 ` Alex Williamson
2021-06-15 16:12 ` Alex Williamson
2021-06-16 6:43 ` Tian, Kevin
2021-06-16 6:43 ` Tian, Kevin
2021-06-16 19:39 ` Alex Williamson
2021-06-16 19:39 ` Alex Williamson
2021-06-17 3:39 ` Liu Yi L
2021-06-17 3:39 ` Liu Yi L
2021-06-17 7:31 ` Tian, Kevin
2021-06-17 7:31 ` Tian, Kevin
2021-06-17 21:14 ` Alex Williamson
2021-06-17 21:14 ` Alex Williamson
2021-06-18 0:19 ` Jason Gunthorpe
2021-06-18 0:19 ` Jason Gunthorpe
2021-06-18 16:57 ` Tian, Kevin
2021-06-18 16:57 ` Tian, Kevin
2021-06-18 18:23 ` Jason Gunthorpe
2021-06-18 18:23 ` Jason Gunthorpe
2021-06-25 10:27 ` Tian, Kevin
2021-06-25 10:27 ` Tian, Kevin
2021-06-25 14:36 ` Jason Gunthorpe
2021-06-25 14:36 ` Jason Gunthorpe
2021-06-28 1:09 ` Tian, Kevin
2021-06-28 1:09 ` Tian, Kevin
2021-06-28 22:31 ` Alex Williamson
2021-06-28 22:31 ` Alex Williamson
2021-06-28 22:48 ` Jason Gunthorpe
2021-06-28 22:48 ` Jason Gunthorpe
2021-06-28 23:09 ` Alex Williamson
2021-06-28 23:09 ` Alex Williamson
2021-06-28 23:13 ` Jason Gunthorpe
2021-06-28 23:13 ` Jason Gunthorpe
2021-06-29 0:26 ` Tian, Kevin
2021-06-29 0:26 ` Tian, Kevin
2021-06-29 0:28 ` Tian, Kevin
2021-06-29 0:28 ` Tian, Kevin
2021-06-29 0:43 ` Tian, Kevin
2021-06-29 0:43 ` Tian, Kevin
2021-06-28 2:03 ` Tian, Kevin [this message]
2021-06-28 2:03 ` Tian, Kevin
2021-06-28 14:41 ` Jason Gunthorpe
2021-06-28 14:41 ` Jason Gunthorpe
2021-06-28 6:45 ` Tian, Kevin
2021-06-28 6:45 ` Tian, Kevin
2021-06-28 16:26 ` Jason Gunthorpe
2021-06-28 16:26 ` Jason Gunthorpe
2021-06-24 4:26 ` David Gibson
2021-06-24 4:26 ` David Gibson
2021-06-24 5:59 ` Tian, Kevin
2021-06-24 5:59 ` Tian, Kevin
2021-06-24 12:22 ` Lu Baolu
2021-06-24 12:22 ` Lu Baolu
2021-06-24 4:23 ` David Gibson
2021-06-24 4:23 ` David Gibson
2021-06-18 0:52 ` Jason Gunthorpe
2021-06-18 0:52 ` Jason Gunthorpe
2021-06-18 13:47 ` Joerg Roedel
2021-06-18 13:47 ` Joerg Roedel
2021-06-18 15:15 ` Jason Gunthorpe
2021-06-18 15:15 ` Jason Gunthorpe
2021-06-18 15:37 ` Raj, Ashok
2021-06-18 15:37 ` Raj, Ashok
2021-06-18 15:51 ` Alex Williamson
2021-06-18 15:51 ` Alex Williamson
2021-06-24 4:29 ` David Gibson
2021-06-24 4:29 ` David Gibson
2021-06-24 11:56 ` Jason Gunthorpe
2021-06-24 11:56 ` Jason Gunthorpe
2021-06-18 0:10 ` Jason Gunthorpe
2021-06-18 0:10 ` Jason Gunthorpe
2021-06-17 5:29 ` David Gibson
2021-06-17 5:29 ` David Gibson
2021-06-17 5:02 ` David Gibson
2021-06-17 5:02 ` David Gibson
2021-06-17 23:04 ` Jason Gunthorpe
2021-06-17 23:04 ` Jason Gunthorpe
2021-06-24 4:37 ` David Gibson
2021-06-24 4:37 ` David Gibson
2021-06-24 11:57 ` Jason Gunthorpe
2021-06-24 11:57 ` Jason Gunthorpe
2021-06-10 5:50 ` Lu Baolu
2021-06-10 5:50 ` Lu Baolu
2021-06-17 5:22 ` David Gibson
2021-06-17 5:22 ` David Gibson
2021-06-18 5:21 ` Lu Baolu
2021-06-18 5:21 ` Lu Baolu
2021-06-24 4:03 ` David Gibson
2021-06-24 4:03 ` David Gibson
2021-06-24 13:42 ` Lu Baolu
2021-06-24 13:42 ` Lu Baolu
2021-06-17 4:45 ` David Gibson
2021-06-17 4:45 ` David Gibson
2021-06-17 23:10 ` Jason Gunthorpe
2021-06-17 23:10 ` Jason Gunthorpe
2021-06-24 4:07 ` David Gibson
2021-06-24 4:07 ` David Gibson
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