linux-kernel - Re: [PATCH 0/2] iommu/vt-d: Select PCI_PRI for INTEL_IOMMU

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Message-ID: <20191015114642.GL14518@8bytes.org>
Date:   Tue, 15 Oct 2019 13:46:42 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     Bjorn Helgaas <helgaas@...nel.org>
Cc:     Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        David Woodhouse <dwmw2@...radead.org>,
        Ashok Raj <ashok.raj@...el.com>,
        Keith Busch <keith.busch@...el.com>, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org,
        Bjorn Helgaas <bhelgaas@...gle.com>
Subject: Re: [PATCH 0/2] iommu/vt-d: Select PCI_PRI for INTEL_IOMMU_SVM

Hey Bjorn,

On Wed, Oct 09, 2019 at 05:45:49PM -0500, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@...gle.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.

Indeed, this is very wrong, thanks for fixing it. Feel free to apply
this series to your tree with my:

Reviewed-by: Joerg Roedel <jroedel@...e.de>
Acked-by: Joerg Roedel <jroedel@...e.de>