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[PATCH 1/3] MAINTAINERS: Add Jonathan Derrick as VMD maintainer

Started byJon Derrick <jonathan.derrick@intel.com>
First post2017-08-07 22:00 +0200
Last post2017-08-11 20:20 +0200
Articles 7 — 4 participants

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Contents

  [PATCH 1/3] MAINTAINERS: Add Jonathan Derrick as VMD maintainer Jon Derrick <jonathan.derrick@intel.com> - 2017-08-07 22:00 +0200
    [PATCH 3/3] iommu: prevent VMD child devices from being remapping targets Jon Derrick <jonathan.derrick@intel.com> - 2017-08-07 22:00 +0200
      Re: [PATCH 3/3] iommu: prevent VMD child devices from being  remapping targets Bjorn Helgaas <helgaas@kernel.org> - 2017-08-11 19:20 +0200
      Re: [PATCH 3/3] iommu: prevent VMD child devices from being remapping  targets Robin Murphy <robin.murphy@arm.com> - 2017-08-11 20:30 +0200
        Re: [PATCH 3/3] iommu: prevent VMD child devices from being remapping  targets Jon Derrick <jonathan.derrick@intel.com> - 2017-08-11 20:50 +0200
    Re: [PATCH 1/3] MAINTAINERS: Add Jonathan Derrick as VMD maintainer Bjorn Helgaas <helgaas@kernel.org> - 2017-08-11 19:30 +0200
    Re: [PATCH 1/3] MAINTAINERS: Add Jonathan Derrick as VMD maintainer Keith Busch <keith.busch@intel.com> - 2017-08-11 20:20 +0200

#1705823 — [PATCH 1/3] MAINTAINERS: Add Jonathan Derrick as VMD maintainer

FromJon Derrick <jonathan.derrick@intel.com>
Date2017-08-07 22:00 +0200
Subject[PATCH 1/3] MAINTAINERS: Add Jonathan Derrick as VMD maintainer
Message-ID<ubWlX-4Np-3@gated-at.bofh.it>
Add myself as VMD maintainer

Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
---
 MAINTAINERS | 1 +
 1 file changed, 1 insertion(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index f66488d..3ec39df 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10090,6 +10090,7 @@ F:	drivers/pci/dwc/*imx6*
 
 PCI DRIVER FOR INTEL VOLUME MANAGEMENT DEVICE (VMD)
 M:	Keith Busch <keith.busch@intel.com>
+M:	Jonathan Derrick <jonathan.derrick@intel.com>
 L:	linux-pci@vger.kernel.org
 S:	Supported
 F:	drivers/pci/host/vmd.c
-- 
2.9.4

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#1705826 — [PATCH 3/3] iommu: prevent VMD child devices from being remapping targets

FromJon Derrick <jonathan.derrick@intel.com>
Date2017-08-07 22:00 +0200
Subject[PATCH 3/3] iommu: prevent VMD child devices from being remapping targets
Message-ID<ubWlY-4Np-21@gated-at.bofh.it>
In reply to#1705823
VMD child devices must use the VMD endpoint's ID as the DMA source.
Because of this, there needs to be a way to link the parent VMD
endpoint's DMAR domain to the VMD child devices' DMAR domain such that
attaching and detaching child devices modify the endpoint's DMAR mapping
and prevents early detaching.

This is outside the scope of VMD, so disable binding child devices to
prevent unforeseen issues. This functionality may be implemented in the
future.

This patch prevents VMD child devices from returning an IOMMU, which
prevents it from exposing iommu_group sysfs directories and subsequent
binding by userspace-access drivers such as VFIO.

Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
---
 drivers/iommu/intel-iommu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 687f18f..651a6cd 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -905,6 +905,11 @@ static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devf
 		 * the PF instead to find the IOMMU. */
 		pf_pdev = pci_physfn(pdev);
 		dev = &pf_pdev->dev;
+
+		/* VMD child devices currently cannot be handled individually */
+		if (pci_bus_is_vmd(pdev->bus))
+			return NULL;
+
 		segment = pci_domain_nr(pdev->bus);
 	} else if (has_acpi_companion(dev))
 		dev = &ACPI_COMPANION(dev)->dev;
-- 
2.9.4

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#1709871 — Re: [PATCH 3/3] iommu: prevent VMD child devices from being remapping targets

FromBjorn Helgaas <helgaas@kernel.org>
Date2017-08-11 19:20 +0200
SubjectRe: [PATCH 3/3] iommu: prevent VMD child devices from being remapping targets
Message-ID<udlLj-6j5-7@gated-at.bofh.it>
In reply to#1705826
On Mon, Aug 07, 2017 at 01:57:13PM -0600, Jon Derrick wrote:
> VMD child devices must use the VMD endpoint's ID as the DMA source.
> Because of this, there needs to be a way to link the parent VMD
> endpoint's DMAR domain to the VMD child devices' DMAR domain such that
> attaching and detaching child devices modify the endpoint's DMAR mapping
> and prevents early detaching.
> 
> This is outside the scope of VMD, so disable binding child devices to
> prevent unforeseen issues. This functionality may be implemented in the
> future.
> 
> This patch prevents VMD child devices from returning an IOMMU, which
> prevents it from exposing iommu_group sysfs directories and subsequent
> binding by userspace-access drivers such as VFIO.
> 
> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
> ---
>  drivers/iommu/intel-iommu.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 687f18f..651a6cd 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -905,6 +905,11 @@ static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devf
>  		 * the PF instead to find the IOMMU. */
>  		pf_pdev = pci_physfn(pdev);
>  		dev = &pf_pdev->dev;
> +
> +		/* VMD child devices currently cannot be handled individually */
> +		if (pci_bus_is_vmd(pdev->bus))

Aah, this is the bigger reason why you want a general "is VMD" thing.
But this is still basically x86-specific code (I do see the ia64 in
Kconfig, so I guess maybe ia64 as well).

But pci_bus_is_vmd() doesn't feel like a generally useful concept.  I
see why you need things like this quirk, but it's not clear what
useful things other code could do with pci_bus_is_vmd() because we
don't have a generic concept of how VMD buses are different than other
PCI buses.

> +			return NULL;
> +
>  		segment = pci_domain_nr(pdev->bus);
>  	} else if (has_acpi_companion(dev))
>  		dev = &ACPI_COMPANION(dev)->dev;
> -- 
> 2.9.4
>

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#1709903 — Re: [PATCH 3/3] iommu: prevent VMD child devices from being remapping targets

FromRobin Murphy <robin.murphy@arm.com>
Date2017-08-11 20:30 +0200
SubjectRe: [PATCH 3/3] iommu: prevent VMD child devices from being remapping targets
Message-ID<udmR3-6UV-3@gated-at.bofh.it>
In reply to#1705826
On 07/08/17 20:57, Jon Derrick wrote:
> VMD child devices must use the VMD endpoint's ID as the DMA source.
> Because of this, there needs to be a way to link the parent VMD
> endpoint's DMAR domain to the VMD child devices' DMAR domain such that
> attaching and detaching child devices modify the endpoint's DMAR mapping
> and prevents early detaching.

That sounds like either pci_device_group() needs modifying, or perhaps
that intel-iommu needs its own extended iommu_ops::device_group
implementation, to ensure that VMD child devices get put in the same
group as their parent - if they share requester IDs they can't feasibly
be attached to different domains anyway.

Robin.

> This is outside the scope of VMD, so disable binding child devices to
> prevent unforeseen issues. This functionality may be implemented in the
> future.
> 
> This patch prevents VMD child devices from returning an IOMMU, which
> prevents it from exposing iommu_group sysfs directories and subsequent
> binding by userspace-access drivers such as VFIO.
> 
> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
> ---
>  drivers/iommu/intel-iommu.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 687f18f..651a6cd 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -905,6 +905,11 @@ static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devf
>  		 * the PF instead to find the IOMMU. */
>  		pf_pdev = pci_physfn(pdev);
>  		dev = &pf_pdev->dev;
> +
> +		/* VMD child devices currently cannot be handled individually */
> +		if (pci_bus_is_vmd(pdev->bus))
> +			return NULL;
> +
>  		segment = pci_domain_nr(pdev->bus);
>  	} else if (has_acpi_companion(dev))
>  		dev = &ACPI_COMPANION(dev)->dev;
>

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#1709913 — Re: [PATCH 3/3] iommu: prevent VMD child devices from being remapping targets

FromJon Derrick <jonathan.derrick@intel.com>
Date2017-08-11 20:50 +0200
SubjectRe: [PATCH 3/3] iommu: prevent VMD child devices from being remapping targets
Message-ID<udnap-72o-13@gated-at.bofh.it>
In reply to#1709903
Hi Robin, thanks for the reply.

On 08/11/2017 12:25 PM, Robin Murphy wrote:
> On 07/08/17 20:57, Jon Derrick wrote:
>> VMD child devices must use the VMD endpoint's ID as the DMA source.
>> Because of this, there needs to be a way to link the parent VMD
>> endpoint's DMAR domain to the VMD child devices' DMAR domain such that
>> attaching and detaching child devices modify the endpoint's DMAR mapping
>> and prevents early detaching.
> > That sounds like either pci_device_group() needs modifying, or perhaps
> that intel-iommu needs its own extended iommu_ops::device_group
> implementation, to ensure that VMD child devices get put in the same
> group as their parent - if they share requester IDs they can't feasibly
> be attached to different domains anyway.
> 
> Robin.
Yes it seems like that to me too. I have a high-level understanding of
the changes required but not too much in the nitty-gritty details. It's
a bit more complicated anyways because VMD emerges a set of root ports,
and AFAICT, PCI ACS end at the root ports and iommu groups rely on ACS
to group devices. Either way it's not within the scope of VMD.

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#1709879

FromBjorn Helgaas <helgaas@kernel.org>
Date2017-08-11 19:30 +0200
Message-ID<udlUZ-6mk-21@gated-at.bofh.it>
In reply to#1705823
On Mon, Aug 07, 2017 at 01:57:11PM -0600, Jon Derrick wrote:
> Add myself as VMD maintainer
> 
> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>

Keith, I'm looking for an ack from you since you're currently
listed in MAINTAINERS.

> ---
>  MAINTAINERS | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index f66488d..3ec39df 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -10090,6 +10090,7 @@ F:	drivers/pci/dwc/*imx6*
>  
>  PCI DRIVER FOR INTEL VOLUME MANAGEMENT DEVICE (VMD)
>  M:	Keith Busch <keith.busch@intel.com>
> +M:	Jonathan Derrick <jonathan.derrick@intel.com>
>  L:	linux-pci@vger.kernel.org
>  S:	Supported
>  F:	drivers/pci/host/vmd.c
> -- 
> 2.9.4
>

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#1709901

FromKeith Busch <keith.busch@intel.com>
Date2017-08-11 20:20 +0200
Message-ID<udmHn-6RA-11@gated-at.bofh.it>
In reply to#1705823
On Mon, Aug 07, 2017 at 01:57:11PM -0600, Jon Derrick wrote:
> Add myself as VMD maintainer
> 
> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>

Thanks for adding. 

Acked-by: Keith Busch <keith.busch@intel.com>


> ---
>  MAINTAINERS | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index f66488d..3ec39df 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -10090,6 +10090,7 @@ F:	drivers/pci/dwc/*imx6*
>  
>  PCI DRIVER FOR INTEL VOLUME MANAGEMENT DEVICE (VMD)
>  M:	Keith Busch <keith.busch@intel.com>
> +M:	Jonathan Derrick <jonathan.derrick@intel.com>
>  L:	linux-pci@vger.kernel.org
>  S:	Supported
>  F:	drivers/pci/host/vmd.c
> -- 
> 2.9.4
>

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