IOMMU Archive on
 help / color / Atom feed
From: Bjorn Helgaas <>
To: Kuppuswamy Sathyanarayanan
	David Woodhouse <>,
	Joerg Roedel <>
Cc: Ashok Raj <>,,,
	Keith Busch <>,,
	Bjorn Helgaas <>
Subject: [PATCH 0/2] iommu/vt-d: Select PCI_PRI for INTEL_IOMMU_SVM
Date: Wed,  9 Oct 2019 17:45:49 -0500
Message-ID: <> (raw)

From: Bjorn Helgaas <>

I think intel-iommu.c depends on CONFIG_AMD_IOMMU in an undesirable way:

When CONFIG_INTEL_IOMMU_SVM=y, iommu_enable_dev_iotlb() calls PRI
interfaces (pci_reset_pri() and pci_enable_pri()), but those are only
implemented when CONFIG_PCI_PRI is enabled.  If CONFIG_PCI_PRI is not
enabled, there are stubs that just return failure.

The INTEL_IOMMU_SVM Kconfig does nothing with PCI_PRI, but AMD_IOMMU
selects PCI_PRI.  So if AMD_IOMMU is enabled, intel-iommu.c gets the full
PRI interfaces.  If AMD_IOMMU is not enabled, it gets the PRI stubs.

This seems wrong.  The first patch here makes INTEL_IOMMU_SVM select
PCI_PRI so intel-iommu.c always gets the full PRI interfaces.

The second patch moves pci_prg_resp_pasid_required(), which simply returns
a bit from the PCI capability, from #ifdef CONFIG_PCI_PASID to #ifdef
CONFIG_PCI_PRI.  This is related because INTEL_IOMMU_SVM already *does*
select PCI_PASID, so it previously always got pci_prg_resp_pasid_required()
even though it got stubs for other PRI things.

Since these are related and I have several follow-on ATS-related patches in
the queue, I'd like to take these both via the PCI tree.

Bjorn Helgaas (2):
  iommu/vt-d: Select PCI_PRI for INTEL_IOMMU_SVM
  PCI/ATS: Move pci_prg_resp_pasid_required() to CONFIG_PCI_PRI

 drivers/iommu/Kconfig   |  1 +
 drivers/pci/ats.c       | 55 +++++++++++++++++++----------------------
 include/linux/pci-ats.h | 11 ++++-----
 3 files changed, 31 insertions(+), 36 deletions(-)


iommu mailing list

             reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-09 22:45 Bjorn Helgaas [this message]
2019-10-09 22:45 ` [PATCH 1/2] " Bjorn Helgaas
2019-10-09 23:42   ` Kuppuswamy Sathyanarayanan
2019-10-09 22:45 ` [PATCH 2/2] PCI/ATS: Move pci_prg_resp_pasid_required() to CONFIG_PCI_PRI Bjorn Helgaas
2019-10-09 22:55   ` Kuppuswamy Sathyanarayanan
2019-10-09 23:50 ` [PATCH 0/2] iommu/vt-d: Select PCI_PRI for INTEL_IOMMU_SVM Jerry Snitselaar
2019-10-15 11:46 ` Joerg Roedel
2019-10-15 21:40 ` Bjorn Helgaas

Reply instructions:

You may reply publically 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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

IOMMU Archive on

Archives are clonable:
	git clone --mirror linux-iommu/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-iommu linux-iommu/ \
	public-inbox-index linux-iommu

Example config snippet for mirrors

Newsgroup available over NNTP:

AGPL code for this site: git clone