From: Jason Gunthorpe via iommu <iommu@lists.linux-foundation.org>
To: "Tian, Kevin" <kevin.tian@intel.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>,
"Raj, Ashok" <ashok.raj@intel.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"rafael@kernel.org" <rafael@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Cornelia Huck <cohuck@redhat.com>, Will Deacon <will@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
Christoph Hellwig <hch@infradead.org>,
Alex Williamson <alex.williamson@redhat.com>,
"Pan, Jacob jun" <jacob.jun.pan@intel.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Diana Craciun <diana.craciun@oss.nxp.com>
Subject: Re: [PATCH 01/11] iommu: Add device dma ownership set/release interfaces
Date: Fri, 19 Nov 2021 08:56:18 -0400 [thread overview]
Message-ID: <20211119125618.GU2105516@nvidia.com> (raw)
In-Reply-To: <BN9PR11MB5433E5B63E575E2232DFBBE48C9C9@BN9PR11MB5433.namprd11.prod.outlook.com>
On Fri, Nov 19, 2021 at 05:44:35AM +0000, Tian, Kevin wrote:
> Well, the difference is just in literal. I don't know the background
> why the existing iommu_attach_device() users want to do it this
> way. But given the condition in iommu_attach_device() it could
> in theory imply some unknown hardware-level side effect which
> may break the desired functionality once the group size grows
> beyond singleton. Is it a real case? I don't know...
No, this must not be.
Any device can have VFIO attached to it, and VFIO does the equivalent
of iommu_attach_device(). We cannot have "unknown hardware-level side
effects" to changing the domain's of multi device groups and also have
working VFIO.
If these HW problems exist they are a seperate issue and the iommu
core should flag such groups as being unable to change their domains
at all.
Jason
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WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@nvidia.com>
To: "Tian, Kevin" <kevin.tian@intel.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
Christoph Hellwig <hch@infradead.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Joerg Roedel <joro@8bytes.org>,
Alex Williamson <alex.williamson@redhat.com>,
Bjorn Helgaas <bhelgaas@google.com>,
"Raj, Ashok" <ashok.raj@intel.com>,
Chaitanya Kulkarni <kch@nvidia.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"rafael@kernel.org" <rafael@kernel.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
Cornelia Huck <cohuck@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"Pan, Jacob jun" <jacob.jun.pan@intel.com>,
Diana Craciun <diana.craciun@oss.nxp.com>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH 01/11] iommu: Add device dma ownership set/release interfaces
Date: Fri, 19 Nov 2021 08:56:18 -0400 [thread overview]
Message-ID: <20211119125618.GU2105516@nvidia.com> (raw)
In-Reply-To: <BN9PR11MB5433E5B63E575E2232DFBBE48C9C9@BN9PR11MB5433.namprd11.prod.outlook.com>
On Fri, Nov 19, 2021 at 05:44:35AM +0000, Tian, Kevin wrote:
> Well, the difference is just in literal. I don't know the background
> why the existing iommu_attach_device() users want to do it this
> way. But given the condition in iommu_attach_device() it could
> in theory imply some unknown hardware-level side effect which
> may break the desired functionality once the group size grows
> beyond singleton. Is it a real case? I don't know...
No, this must not be.
Any device can have VFIO attached to it, and VFIO does the equivalent
of iommu_attach_device(). We cannot have "unknown hardware-level side
effects" to changing the domain's of multi device groups and also have
working VFIO.
If these HW problems exist they are a seperate issue and the iommu
core should flag such groups as being unable to change their domains
at all.
Jason
next prev parent reply other threads:[~2021-11-19 12:56 UTC|newest]
Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-15 2:05 [PATCH 00/11] Fix BUG_ON in vfio_iommu_group_notifier() Lu Baolu
2021-11-15 2:05 ` Lu Baolu
2021-11-15 2:05 ` [PATCH 01/11] iommu: Add device dma ownership set/release interfaces Lu Baolu
2021-11-15 2:05 ` Lu Baolu
2021-11-15 13:14 ` Christoph Hellwig
2021-11-15 13:14 ` Christoph Hellwig
2021-11-16 1:57 ` Lu Baolu
2021-11-16 1:57 ` Lu Baolu
2021-11-16 13:46 ` Jason Gunthorpe via iommu
2021-11-16 13:46 ` Jason Gunthorpe
2021-11-17 5:22 ` Lu Baolu
2021-11-17 5:22 ` Lu Baolu
2021-11-17 13:35 ` Jason Gunthorpe via iommu
2021-11-17 13:35 ` Jason Gunthorpe
2021-11-18 1:12 ` Lu Baolu
2021-11-18 1:12 ` Lu Baolu
2021-11-18 14:10 ` Jason Gunthorpe via iommu
2021-11-18 14:10 ` Jason Gunthorpe
2021-11-18 2:39 ` Tian, Kevin
2021-11-18 2:39 ` Tian, Kevin
2021-11-18 13:33 ` Jason Gunthorpe via iommu
2021-11-18 13:33 ` Jason Gunthorpe
2021-11-19 5:44 ` Tian, Kevin
2021-11-19 5:44 ` Tian, Kevin
2021-11-19 11:14 ` Lu Baolu
2021-11-19 11:14 ` Lu Baolu
2021-11-19 15:06 ` Jörg Rödel
2021-11-19 15:06 ` Jörg Rödel
2021-11-19 15:43 ` Jason Gunthorpe via iommu
2021-11-19 15:43 ` Jason Gunthorpe
2021-11-20 11:16 ` Lu Baolu
2021-11-20 11:16 ` Lu Baolu
2021-11-19 12:56 ` Jason Gunthorpe via iommu [this message]
2021-11-19 12:56 ` Jason Gunthorpe
2021-11-15 20:38 ` Bjorn Helgaas
2021-11-15 20:38 ` Bjorn Helgaas
2021-11-16 1:52 ` Lu Baolu
2021-11-16 1:52 ` Lu Baolu
2021-11-15 2:05 ` [PATCH 02/11] driver core: Set DMA ownership during driver bind/unbind Lu Baolu
2021-11-15 2:05 ` Lu Baolu
2021-11-15 6:59 ` Greg Kroah-Hartman
2021-11-15 6:59 ` Greg Kroah-Hartman
2021-11-15 13:20 ` Christoph Hellwig
2021-11-15 13:20 ` Christoph Hellwig
2021-11-15 13:38 ` Jason Gunthorpe via iommu
2021-11-15 13:38 ` Jason Gunthorpe
2021-11-15 13:19 ` Christoph Hellwig
2021-11-15 13:19 ` Christoph Hellwig
2021-11-15 13:24 ` Jason Gunthorpe via iommu
2021-11-15 13:24 ` Jason Gunthorpe
2021-11-15 15:37 ` Robin Murphy
2021-11-15 15:37 ` Robin Murphy
2021-11-15 15:56 ` Jason Gunthorpe via iommu
2021-11-15 15:56 ` Jason Gunthorpe
2021-11-15 18:15 ` Christoph Hellwig
2021-11-15 18:15 ` Christoph Hellwig
2021-11-15 18:35 ` Robin Murphy
2021-11-15 18:35 ` Robin Murphy
2021-11-15 19:39 ` Jason Gunthorpe via iommu
2021-11-15 19:39 ` Jason Gunthorpe
2021-11-15 2:05 ` [PATCH 03/11] PCI: pci_stub: Suppress kernel DMA ownership auto-claiming Lu Baolu
2021-11-15 2:05 ` Lu Baolu
2021-11-15 13:21 ` Christoph Hellwig
2021-11-15 13:21 ` Christoph Hellwig
2021-11-15 13:31 ` Jason Gunthorpe via iommu
2021-11-15 13:31 ` Jason Gunthorpe
2021-11-15 15:14 ` Robin Murphy
2021-11-15 15:14 ` Robin Murphy
2021-11-15 16:17 ` Jason Gunthorpe via iommu
2021-11-15 16:17 ` Jason Gunthorpe
2021-11-15 17:54 ` Robin Murphy
2021-11-15 17:54 ` Robin Murphy
2021-11-15 18:19 ` Christoph Hellwig
2021-11-15 18:19 ` Christoph Hellwig
2021-11-15 18:44 ` Robin Murphy
2021-11-15 18:44 ` Robin Murphy
2021-11-15 19:22 ` Jason Gunthorpe via iommu
2021-11-15 19:22 ` Jason Gunthorpe
2021-11-15 20:58 ` Robin Murphy
2021-11-15 20:58 ` Robin Murphy
2021-11-15 21:19 ` Jason Gunthorpe via iommu
2021-11-15 21:19 ` Jason Gunthorpe
2021-11-15 20:48 ` Bjorn Helgaas
2021-11-15 20:48 ` Bjorn Helgaas
2021-11-15 22:17 ` Bjorn Helgaas
2021-11-15 22:17 ` Bjorn Helgaas
2021-11-16 6:05 ` Lu Baolu
2021-11-16 6:05 ` Lu Baolu
2021-11-15 2:05 ` [PATCH 04/11] PCI: portdrv: " Lu Baolu
2021-11-15 2:05 ` Lu Baolu
2021-11-15 20:44 ` Bjorn Helgaas
2021-11-15 20:44 ` Bjorn Helgaas
2021-11-16 7:24 ` Lu Baolu
2021-11-16 7:24 ` Lu Baolu
2021-11-16 20:22 ` Bjorn Helgaas
2021-11-16 20:22 ` Bjorn Helgaas
2021-11-16 20:48 ` Jason Gunthorpe via iommu
2021-11-16 20:48 ` Jason Gunthorpe
2021-11-15 2:05 ` [PATCH 05/11] iommu: Add security context management for assigned devices Lu Baolu
2021-11-15 2:05 ` Lu Baolu
2021-11-15 13:22 ` Christoph Hellwig
2021-11-15 13:22 ` Christoph Hellwig
2021-11-16 7:25 ` Lu Baolu
2021-11-16 7:25 ` Lu Baolu
2021-11-15 2:05 ` [PATCH 06/11] iommu: Expose group variants of dma ownership interfaces Lu Baolu
2021-11-15 2:05 ` Lu Baolu
2021-11-15 13:27 ` Christoph Hellwig
2021-11-15 13:27 ` Christoph Hellwig
2021-11-16 9:42 ` Lu Baolu
2021-11-16 9:42 ` Lu Baolu
2021-11-15 2:05 ` [PATCH 07/11] vfio: Use DMA_OWNER_USER to declaim passthrough devices Lu Baolu
2021-11-15 2:05 ` Lu Baolu
2021-11-15 2:05 ` [PATCH 08/11] vfio: Remove use of vfio_group_viable() Lu Baolu
2021-11-15 2:05 ` Lu Baolu
2021-11-15 2:05 ` [PATCH 09/11] vfio: Delete the unbound_list Lu Baolu
2021-11-15 2:05 ` Lu Baolu
2021-11-15 2:05 ` [PATCH 10/11] vfio: Remove iommu group notifier Lu Baolu
2021-11-15 2:05 ` Lu Baolu
2021-11-15 2:05 ` [PATCH 11/11] iommu: Remove iommu group changes notifier Lu Baolu
2021-11-15 2:05 ` Lu Baolu
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