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From: Jerry Snitselaar <jsnitsel@redhat.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Ashok Raj <ashok.raj@intel.com>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	Keith Busch <keith.busch@intel.com>,
	iommu@lists.linux-foundation.org,
	Bjorn Helgaas <bhelgaas@google.com>,
	David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH 0/2] iommu/vt-d: Select PCI_PRI for INTEL_IOMMU_SVM
Date: Wed, 9 Oct 2019 16:50:09 -0700
Message-ID: <20191009235009.a3mxw4qrklkqwuzf@cantor> (raw)
In-Reply-To: <20191009224551.179497-1-helgaas@kernel.org>

On Wed Oct 09 19, Bjorn Helgaas wrote:
>From: Bjorn Helgaas <bhelgaas@google.com>
>
>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(-)
>
>-- 
>2.23.0.581.g78d2f28ef7-goog
>
>_______________________________________________
>iommu mailing list
>iommu@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  parent reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-09 22:45 Bjorn Helgaas
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 ` Jerry Snitselaar [this message]
2019-10-15 11:46 ` [PATCH 0/2] iommu/vt-d: Select PCI_PRI for INTEL_IOMMU_SVM Joerg Roedel
2019-10-15 21:40 ` Bjorn Helgaas

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