From: Lu Baolu <baolu.lu@linux.intel.com> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Joerg Roedel <joro@8bytes.org>, Alex Williamson <alex.williamson@redhat.com>, Bjorn Helgaas <bhelgaas@google.com>, Jason Gunthorpe <jgg@nvidia.com>, Kevin Tian <kevin.tian@intel.com>, Ashok Raj <ashok.raj@intel.com> Cc: Will Deacon <will@kernel.org>, 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>, iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Lu Baolu <baolu.lu@linux.intel.com> Subject: [PATCH 04/11] PCI: portdrv: Suppress kernel DMA ownership auto-claiming Date: Mon, 15 Nov 2021 10:05:45 +0800 [thread overview] Message-ID: <20211115020552.2378167-5-baolu.lu@linux.intel.com> (raw) In-Reply-To: <20211115020552.2378167-1-baolu.lu@linux.intel.com> IOMMU grouping on PCI necessitates that if we lack isolation on a bridge then all of the downstream devices will be part of the same IOMMU group as the bridge. As long as the bridge kernel driver doesn't map and access any PCI mmio bar, it's safe to bind it to the device in a USER- owned group. Hence, safe to suppress the kernel DMA ownership auto- claiming. The commit 5f096b14d421b ("vfio: Whitelist PCI bridges") permitted a class of kernel drivers. This is not always safe. For example, the SHPC system design requires that it must be integrated into a PCI-to-PCI bridge or a host bridge. The shpchp_core driver relies on the PCI mmio bar access for the controller functionality. Binding it to the device belonging to a USER-owned group will allow the user to change the controller via p2p transactions which is unknown to the hot-plug driver and could lead to some unpredictable consequences. Now that we have driver self-declaration of safety we should rely on that. This change may cause regression on some platforms, since all bridges were exempted before, but now they have to be manually audited before doing so. This is actually the desired outcome anyway. Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Suggested-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> --- drivers/pci/pcie/portdrv_pci.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c index 35eca6277a96..1285862a9aa8 100644 --- a/drivers/pci/pcie/portdrv_pci.c +++ b/drivers/pci/pcie/portdrv_pci.c @@ -203,6 +203,8 @@ static struct pci_driver pcie_portdriver = { .err_handler = &pcie_portdrv_err_handler, .driver.pm = PCIE_PORTDRV_PM_OPS, + + .driver.suppress_auto_claim_dma_owner = true, }; static int __init dmi_pcie_pme_disable_msi(const struct dmi_system_id *d) -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: Lu Baolu <baolu.lu@linux.intel.com> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Joerg Roedel <joro@8bytes.org>, Alex Williamson <alex.williamson@redhat.com>, Bjorn Helgaas <bhelgaas@google.com>, Jason Gunthorpe <jgg@nvidia.com>, Kevin Tian <kevin.tian@intel.com>, Ashok Raj <ashok.raj@intel.com> Cc: Chaitanya Kulkarni <kch@nvidia.com>, kvm@vger.kernel.org, rafael@kernel.org, linux-pci@vger.kernel.org, Cornelia Huck <cohuck@redhat.com>, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Jacob jun Pan <jacob.jun.pan@intel.com>, Diana Craciun <diana.craciun@oss.nxp.com>, Will Deacon <will@kernel.org> Subject: [PATCH 04/11] PCI: portdrv: Suppress kernel DMA ownership auto-claiming Date: Mon, 15 Nov 2021 10:05:45 +0800 [thread overview] Message-ID: <20211115020552.2378167-5-baolu.lu@linux.intel.com> (raw) In-Reply-To: <20211115020552.2378167-1-baolu.lu@linux.intel.com> IOMMU grouping on PCI necessitates that if we lack isolation on a bridge then all of the downstream devices will be part of the same IOMMU group as the bridge. As long as the bridge kernel driver doesn't map and access any PCI mmio bar, it's safe to bind it to the device in a USER- owned group. Hence, safe to suppress the kernel DMA ownership auto- claiming. The commit 5f096b14d421b ("vfio: Whitelist PCI bridges") permitted a class of kernel drivers. This is not always safe. For example, the SHPC system design requires that it must be integrated into a PCI-to-PCI bridge or a host bridge. The shpchp_core driver relies on the PCI mmio bar access for the controller functionality. Binding it to the device belonging to a USER-owned group will allow the user to change the controller via p2p transactions which is unknown to the hot-plug driver and could lead to some unpredictable consequences. Now that we have driver self-declaration of safety we should rely on that. This change may cause regression on some platforms, since all bridges were exempted before, but now they have to be manually audited before doing so. This is actually the desired outcome anyway. Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Suggested-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> --- drivers/pci/pcie/portdrv_pci.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c index 35eca6277a96..1285862a9aa8 100644 --- a/drivers/pci/pcie/portdrv_pci.c +++ b/drivers/pci/pcie/portdrv_pci.c @@ -203,6 +203,8 @@ static struct pci_driver pcie_portdriver = { .err_handler = &pcie_portdrv_err_handler, .driver.pm = PCIE_PORTDRV_PM_OPS, + + .driver.suppress_auto_claim_dma_owner = true, }; static int __init dmi_pcie_pme_disable_msi(const struct dmi_system_id *d) -- 2.25.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2021-11-15 2:13 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 2021-11-16 13:46 ` Jason Gunthorpe via iommu 2021-11-17 5:22 ` Lu Baolu 2021-11-17 5:22 ` Lu Baolu 2021-11-17 13:35 ` Jason Gunthorpe 2021-11-17 13:35 ` Jason Gunthorpe via iommu 2021-11-18 1:12 ` Lu Baolu 2021-11-18 1:12 ` Lu Baolu 2021-11-18 14:10 ` Jason Gunthorpe 2021-11-18 14:10 ` Jason Gunthorpe via iommu 2021-11-18 2:39 ` Tian, Kevin 2021-11-18 2:39 ` Tian, Kevin 2021-11-18 13:33 ` Jason Gunthorpe 2021-11-18 13:33 ` Jason Gunthorpe via iommu 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 2021-11-19 15:43 ` Jason Gunthorpe via iommu 2021-11-20 11:16 ` Lu Baolu 2021-11-20 11:16 ` Lu Baolu 2021-11-19 12:56 ` Jason Gunthorpe 2021-11-19 12:56 ` Jason Gunthorpe via iommu 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 2021-11-15 13:24 ` Jason Gunthorpe via iommu 2021-11-15 15:37 ` Robin Murphy 2021-11-15 15:37 ` Robin Murphy 2021-11-15 15:56 ` Jason Gunthorpe 2021-11-15 15:56 ` Jason Gunthorpe via iommu 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 2021-11-15 16:17 ` Jason Gunthorpe via iommu 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 ` Lu Baolu [this message] 2021-11-15 2:05 ` [PATCH 04/11] PCI: portdrv: " 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 2021-11-16 20:48 ` Jason Gunthorpe via iommu 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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