[PATCH v5 0/7] Clean up VMD DMA Map Ops

[PATCH v5 0/7] Clean up VMD DMA Map Ops

[Jon Derrick]

v4 Set: https://lore.kernel.org/linux-pci/20200120110220.GB17267@e121166-lin.cambridge.arm.com/T/#t
v3 Set: https://lore.kernel.org/linux-iommu/20200113181742.GA27623@e121166-lin.cambridge.arm.com/T/#t
v2 Set: https://lore.kernel.org/linux-iommu/1578580256-3483-1-git-send-email-jonathan.derrick@intel.com/T/#t
v1 Set: https://lore.kernel.org/linux-iommu/20200107134125.GD30750@8bytes.org/T/#t

VMD currently works with VT-d enabled by pointing DMA and IOMMU actions at the
VMD endpoint. The problem with this approach is that the VMD endpoint's
device-specific attributes, such as the DMA Mask Bits, are used instead of the
child device's attributes.

This set cleans up VMD by removing the override that redirects DMA map
operations to the VMD endpoint. Instead it introduces a new DMA alias mechanism
into the existing DMA alias infrastructure. This new DMA alias mechanism allows
an architecture-specific pci_real_dma_dev() function to provide a pointer from
a pci_dev to its PCI DMA device, where by default it returns the original
pci_dev.

In addition, this set removes the sanity check that was added to prevent
assigning VMD child devices. By using the DMA alias mechanism, all child
devices are assigned the same IOMMU group as the VMD endpoint. This removes the
need for restricting VMD child devices from assignment, as the whole group
would have to be assigned, requiring unbinding the VMD driver and removing the
child device domain.

v1 added a pointer in struct pci_dev that pointed to the DMA alias' struct
pci_dev and did the necessary DMA alias and IOMMU modifications.

v2 introduced a new weak function to reference the 'Direct DMA Alias', and
removed the need to add a pointer in struct device or pci_dev. Weak functions
are generally frowned upon when it's a single architecture implementation, so I
am open to alternatives.

v3 referenced the pci_dev rather than the struct device for the PCI
'Direct DMA Alias' (pci_direct_dma_alias()). This revision also allowed
pci_for_each_dma_alias() to call any DMA aliases for the Direct DMA alias
device, though I don't expect the VMD endpoint to need intra-bus DMA aliases.

v4 changes the 'Direct DMA Alias' to instead refer to the 'Real DMA Dev', which
either returns the PCI device itself or the PCI DMA device.

v5 Fixes a bad call argument to pci_real_dma_dev that would have broken
bisection. This revision also changes one of the calls to a one-liner, and
assembles the same on my system.


Changes from v4:
Fix pci_real_dma_dev() call in 4/7.
Change other pci_real_dma_dev() call in 4/7 to one-liner.

Changes from v3:
Uses pci_real_dma_dev() instead of pci_direct_dma_alias()
Split IOMMU enabling, IOMMU VMD sanity check and VMD dma_map_ops cleanup into three patches

Changes from v2:
Uses struct pci_dev for PCI Device 'Direct DMA aliasing' (pci_direct_dma_alias)
Allows pci_for_each_dma_alias to iterate over the alias mask of the 'Direct DMA alias'

Changes from v1:
Removed 1/5 & 2/5 misc fix patches that were merged
Uses Christoph's staging/cleanup patches
Introduce weak function rather than including pointer in struct device or pci_dev.

Based on Bjorn's next:
https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/log/?h=next

Christoph Hellwig (2):
  x86/PCI: Add a to_pci_sysdata helper
  x86/PCI: Remove X86_DEV_DMA_OPS

Jon Derrick (5):
  x86/PCI: Expose VMD's PCI Device in pci_sysdata
  PCI: Introduce pci_real_dma_dev()
  iommu/vt-d: Use pci_real_dma_dev() for mapping
  iommu/vt-d: Remove VMD child device sanity check
  PCI: vmd: Stop overriding dma_map_ops

 arch/x86/Kconfig               |   3 -
 arch/x86/include/asm/device.h  |  10 ---
 arch/x86/include/asm/pci.h     |  31 ++++-----
 arch/x86/pci/common.c          |  48 +++----------
 drivers/iommu/intel-iommu.c    |  11 ++-
 drivers/pci/controller/Kconfig |   1 -
 drivers/pci/controller/vmd.c   | 152 +----------------------------------------
 drivers/pci/pci.c              |  19 +++++-
 drivers/pci/search.c           |   6 ++
 include/linux/pci.h            |   1 +
 10 files changed, 54 insertions(+), 228 deletions(-)

-- 
1.8.3.1

[PATCH v5 1/7] x86/PCI: Add a to_pci_sysdata helper

[Jon Derrick]

From: Christoph Hellwig <hch@lst.de>

Various helpers need the pci_sysdata just to dereference a single field
in it.  Add a little helper that returns the properly typed sysdata
pointer to require a little less boilerplate code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
[jonathan.derrick: to_pci_sysdata const argument]
Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
---
 arch/x86/include/asm/pci.h | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h
index 90d0731..a4e09db60 100644
--- a/arch/x86/include/asm/pci.h
+++ b/arch/x86/include/asm/pci.h
@@ -35,12 +35,15 @@ struct pci_sysdata {
 
 #ifdef CONFIG_PCI
 
+static inline struct pci_sysdata *to_pci_sysdata(const struct pci_bus *bus)
+{
+	return bus->sysdata;
+}
+
 #ifdef CONFIG_PCI_DOMAINS
 static inline int pci_domain_nr(struct pci_bus *bus)
 {
-	struct pci_sysdata *sd = bus->sysdata;
-
-	return sd->domain;
+	return to_pci_sysdata(bus)->domain;
 }
 
 static inline int pci_proc_domain(struct pci_bus *bus)
@@ -52,24 +55,20 @@ static inline int pci_proc_domain(struct pci_bus *bus)
 #ifdef CONFIG_PCI_MSI_IRQ_DOMAIN
 static inline void *_pci_root_bus_fwnode(struct pci_bus *bus)
 {
-	struct pci_sysdata *sd = bus->sysdata;
-
-	return sd->fwnode;
+	return to_pci_sysdata(bus)->fwnode;
 }
 
 #define pci_root_bus_fwnode	_pci_root_bus_fwnode
 #endif
 
+#if IS_ENABLED(CONFIG_VMD)
 static inline bool is_vmd(struct pci_bus *bus)
 {
-#if IS_ENABLED(CONFIG_VMD)
-	struct pci_sysdata *sd = bus->sysdata;
-
-	return sd->vmd_domain;
-#else
-	return false;
-#endif
+	return to_pci_sysdata(bus)->vmd_domain;
 }
+#else
+#define is_vmd(bus)		false
+#endif /* CONFIG_VMD */
 
 /* Can be used to override the logic in pci_scan_bus for skipping
    already-configured bus numbers - to be used for buggy BIOSes
@@ -124,9 +123,7 @@ static inline void early_quirks(void) { }
 /* Returns the node based on pci bus */
 static inline int __pcibus_to_node(const struct pci_bus *bus)
 {
-	const struct pci_sysdata *sd = bus->sysdata;
-
-	return sd->node;
+	return to_pci_sysdata(bus)->node;
 }
 
 static inline const struct cpumask *
-- 
1.8.3.1

[PATCH v5 2/7] x86/PCI: Expose VMD's PCI Device in pci_sysdata

[Jon Derrick]

To be used by Intel-IOMMU code to find the correct domain.

CC: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
---
 arch/x86/include/asm/pci.h   | 4 ++--
 drivers/pci/controller/vmd.c | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/pci.h b/arch/x86/include/asm/pci.h
index a4e09db60..6512c54 100644
--- a/arch/x86/include/asm/pci.h
+++ b/arch/x86/include/asm/pci.h
@@ -25,7 +25,7 @@ struct pci_sysdata {
 	void		*fwnode;	/* IRQ domain for MSI assignment */
 #endif
 #if IS_ENABLED(CONFIG_VMD)
-	bool vmd_domain;		/* True if in Intel VMD domain */
+	struct pci_dev	*vmd_dev;	/* VMD Device if in Intel VMD domain */
 #endif
 };
 
@@ -64,7 +64,7 @@ static inline void *_pci_root_bus_fwnode(struct pci_bus *bus)
 #if IS_ENABLED(CONFIG_VMD)
 static inline bool is_vmd(struct pci_bus *bus)
 {
-	return to_pci_sysdata(bus)->vmd_domain;
+	return to_pci_sysdata(bus)->vmd_dev != NULL;
 }
 #else
 #define is_vmd(bus)		false
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index 2128422..d67ad56 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -679,7 +679,7 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
 		.parent = res,
 	};
 
-	sd->vmd_domain = true;
+	sd->vmd_dev = vmd->dev;
 	sd->domain = vmd_find_free_domain();
 	if (sd->domain < 0)
 		return sd->domain;
-- 
1.8.3.1

[PATCH v5 3/7] PCI: Introduce pci_real_dma_dev()

[Jon Derrick]

The current DMA alias implementation requires the aliased device be on
the same PCI bus as the requester ID. This introduces an arch-specific
mechanism to point to another PCI device when doing mapping and
PCI DMA alias search. The default case returns the actual device.

CC: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
---
 arch/x86/pci/common.c | 10 ++++++++++
 drivers/pci/pci.c     | 19 ++++++++++++++++++-
 drivers/pci/search.c  |  6 ++++++
 include/linux/pci.h   |  1 +
 4 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index 1e59df0..fe21a5c 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -736,3 +736,13 @@ int pci_ext_cfg_avail(void)
 	else
 		return 0;
 }
+
+#if IS_ENABLED(CONFIG_VMD)
+struct pci_dev *pci_real_dma_dev(struct pci_dev *dev)
+{
+	if (is_vmd(dev->bus))
+		return to_pci_sysdata(dev->bus)->vmd_dev;
+
+	return dev;
+}
+#endif
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 581b177..36d24f2 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -6048,7 +6048,9 @@ bool pci_devs_are_dma_aliases(struct pci_dev *dev1, struct pci_dev *dev2)
 	return (dev1->dma_alias_mask &&
 		test_bit(dev2->devfn, dev1->dma_alias_mask)) ||
 	       (dev2->dma_alias_mask &&
-		test_bit(dev1->devfn, dev2->dma_alias_mask));
+		test_bit(dev1->devfn, dev2->dma_alias_mask)) ||
+	       pci_real_dma_dev(dev1) == dev2 ||
+	       pci_real_dma_dev(dev2) == dev1;
 }
 
 bool pci_device_is_present(struct pci_dev *pdev)
@@ -6072,6 +6074,21 @@ void pci_ignore_hotplug(struct pci_dev *dev)
 }
 EXPORT_SYMBOL_GPL(pci_ignore_hotplug);
 
+/**
+ * pci_real_dma_dev - Get PCI DMA device for PCI device
+ * @dev: the PCI device that may have a PCI DMA alias
+ *
+ * Permits the platform to provide architecture-specific functionality to
+ * devices needing to alias DMA to another PCI device on another PCI bus. If
+ * the PCI device is on the same bus, it is recommended to use
+ * pci_add_dma_alias(). This is the default implementation. Architecture
+ * implementations can override this.
+ */
+struct pci_dev __weak *pci_real_dma_dev(struct pci_dev *dev)
+{
+	return dev;
+}
+
 resource_size_t __weak pcibios_default_alignment(void)
 {
 	return 0;
diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index e4dbdef..2061672 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -32,6 +32,12 @@ int pci_for_each_dma_alias(struct pci_dev *pdev,
 	struct pci_bus *bus;
 	int ret;
 
+	/*
+	 * The device may have an explicit alias requester ID for DMA where the
+	 * requester is on another PCI bus.
+	 */
+	pdev = pci_real_dma_dev(pdev);
+
 	ret = fn(pdev, pci_dev_id(pdev), data);
 	if (ret)
 		return ret;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 930fab2..3840a54 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1202,6 +1202,7 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev,
 int pci_select_bars(struct pci_dev *dev, unsigned long flags);
 bool pci_device_is_present(struct pci_dev *pdev);
 void pci_ignore_hotplug(struct pci_dev *dev);
+struct pci_dev *pci_real_dma_dev(struct pci_dev *dev);
 
 int __printf(6, 7) pci_request_irq(struct pci_dev *dev, unsigned int nr,
 		irq_handler_t handler, irq_handler_t thread_fn, void *dev_id,
-- 
1.8.3.1

Re: [PATCH v5 3/7] PCI: Introduce pci_real_dma_dev()

[Bjorn Helgaas]

On Tue, Jan 21, 2020 at 06:37:47AM -0700, Jon Derrick wrote:
> The current DMA alias implementation requires the aliased device be on
> the same PCI bus as the requester ID. This introduces an arch-specific
> mechanism to point to another PCI device when doing mapping and
> PCI DMA alias search. The default case returns the actual device.
> 
> CC: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

Looks like a nice cleanup to me.

Lorenzo, let me know if you want me to take this.

> ---
>  arch/x86/pci/common.c | 10 ++++++++++
>  drivers/pci/pci.c     | 19 ++++++++++++++++++-
>  drivers/pci/search.c  |  6 ++++++
>  include/linux/pci.h   |  1 +
>  4 files changed, 35 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
> index 1e59df0..fe21a5c 100644
> --- a/arch/x86/pci/common.c
> +++ b/arch/x86/pci/common.c
> @@ -736,3 +736,13 @@ int pci_ext_cfg_avail(void)
>  	else
>  		return 0;
>  }
> +
> +#if IS_ENABLED(CONFIG_VMD)
> +struct pci_dev *pci_real_dma_dev(struct pci_dev *dev)
> +{
> +	if (is_vmd(dev->bus))
> +		return to_pci_sysdata(dev->bus)->vmd_dev;
> +
> +	return dev;
> +}
> +#endif
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 581b177..36d24f2 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -6048,7 +6048,9 @@ bool pci_devs_are_dma_aliases(struct pci_dev *dev1, struct pci_dev *dev2)
>  	return (dev1->dma_alias_mask &&
>  		test_bit(dev2->devfn, dev1->dma_alias_mask)) ||
>  	       (dev2->dma_alias_mask &&
> -		test_bit(dev1->devfn, dev2->dma_alias_mask));
> +		test_bit(dev1->devfn, dev2->dma_alias_mask)) ||
> +	       pci_real_dma_dev(dev1) == dev2 ||
> +	       pci_real_dma_dev(dev2) == dev1;
>  }
>  
>  bool pci_device_is_present(struct pci_dev *pdev)
> @@ -6072,6 +6074,21 @@ void pci_ignore_hotplug(struct pci_dev *dev)
>  }
>  EXPORT_SYMBOL_GPL(pci_ignore_hotplug);
>  
> +/**
> + * pci_real_dma_dev - Get PCI DMA device for PCI device
> + * @dev: the PCI device that may have a PCI DMA alias
> + *
> + * Permits the platform to provide architecture-specific functionality to
> + * devices needing to alias DMA to another PCI device on another PCI bus. If
> + * the PCI device is on the same bus, it is recommended to use
> + * pci_add_dma_alias(). This is the default implementation. Architecture
> + * implementations can override this.
> + */
> +struct pci_dev __weak *pci_real_dma_dev(struct pci_dev *dev)
> +{
> +	return dev;
> +}
> +
>  resource_size_t __weak pcibios_default_alignment(void)
>  {
>  	return 0;
> diff --git a/drivers/pci/search.c b/drivers/pci/search.c
> index e4dbdef..2061672 100644
> --- a/drivers/pci/search.c
> +++ b/drivers/pci/search.c
> @@ -32,6 +32,12 @@ int pci_for_each_dma_alias(struct pci_dev *pdev,
>  	struct pci_bus *bus;
>  	int ret;
>  
> +	/*
> +	 * The device may have an explicit alias requester ID for DMA where the
> +	 * requester is on another PCI bus.
> +	 */
> +	pdev = pci_real_dma_dev(pdev);
>  	ret = fn(pdev, pci_dev_id(pdev), data);
>  	if (ret)
>  		return ret;
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 930fab2..3840a54 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1202,6 +1202,7 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev,
>  int pci_select_bars(struct pci_dev *dev, unsigned long flags);
>  bool pci_device_is_present(struct pci_dev *pdev);
>  void pci_ignore_hotplug(struct pci_dev *dev);
> +struct pci_dev *pci_real_dma_dev(struct pci_dev *dev);
>  
>  int __printf(6, 7) pci_request_irq(struct pci_dev *dev, unsigned int nr,
>  		irq_handler_t handler, irq_handler_t thread_fn, void *dev_id,
> -- 
> 1.8.3.1
> 

Re: [PATCH v5 3/7] PCI: Introduce pci_real_dma_dev()

[Lorenzo Pieralisi]

On Wed, Jan 22, 2020 at 03:12:59PM -0600, Bjorn Helgaas wrote:
> On Tue, Jan 21, 2020 at 06:37:47AM -0700, Jon Derrick wrote:
> > The current DMA alias implementation requires the aliased device be on
> > the same PCI bus as the requester ID. This introduces an arch-specific
> > mechanism to point to another PCI device when doing mapping and
> > PCI DMA alias search. The default case returns the actual device.
> > 
> > CC: Christoph Hellwig <hch@lst.de>
> > Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
> 
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> 
> Looks like a nice cleanup to me.
> 
> Lorenzo, let me know if you want me to take this.

Hi Bjorn,

I think it makes sense for you to take the series given that
it is mostly core/x86 changes. FWIW I Acked the relevant patch
(6) even though Jon forgot to carry it to v5.

Thanks,
Lorenzo

> >  arch/x86/pci/common.c | 10 ++++++++++
> >  drivers/pci/pci.c     | 19 ++++++++++++++++++-
> >  drivers/pci/search.c  |  6 ++++++
> >  include/linux/pci.h   |  1 +
> >  4 files changed, 35 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
> > index 1e59df0..fe21a5c 100644
> > --- a/arch/x86/pci/common.c
> > +++ b/arch/x86/pci/common.c
> > @@ -736,3 +736,13 @@ int pci_ext_cfg_avail(void)
> >  	else
> >  		return 0;
> >  }
> > +
> > +#if IS_ENABLED(CONFIG_VMD)
> > +struct pci_dev *pci_real_dma_dev(struct pci_dev *dev)
> > +{
> > +	if (is_vmd(dev->bus))
> > +		return to_pci_sysdata(dev->bus)->vmd_dev;
> > +
> > +	return dev;
> > +}
> > +#endif
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index 581b177..36d24f2 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -6048,7 +6048,9 @@ bool pci_devs_are_dma_aliases(struct pci_dev *dev1, struct pci_dev *dev2)
> >  	return (dev1->dma_alias_mask &&
> >  		test_bit(dev2->devfn, dev1->dma_alias_mask)) ||
> >  	       (dev2->dma_alias_mask &&
> > -		test_bit(dev1->devfn, dev2->dma_alias_mask));
> > +		test_bit(dev1->devfn, dev2->dma_alias_mask)) ||
> > +	       pci_real_dma_dev(dev1) == dev2 ||
> > +	       pci_real_dma_dev(dev2) == dev1;
> >  }
> >  
> >  bool pci_device_is_present(struct pci_dev *pdev)
> > @@ -6072,6 +6074,21 @@ void pci_ignore_hotplug(struct pci_dev *dev)
> >  }
> >  EXPORT_SYMBOL_GPL(pci_ignore_hotplug);
> >  
> > +/**
> > + * pci_real_dma_dev - Get PCI DMA device for PCI device
> > + * @dev: the PCI device that may have a PCI DMA alias
> > + *
> > + * Permits the platform to provide architecture-specific functionality to
> > + * devices needing to alias DMA to another PCI device on another PCI bus. If
> > + * the PCI device is on the same bus, it is recommended to use
> > + * pci_add_dma_alias(). This is the default implementation. Architecture
> > + * implementations can override this.
> > + */
> > +struct pci_dev __weak *pci_real_dma_dev(struct pci_dev *dev)
> > +{
> > +	return dev;
> > +}
> > +
> >  resource_size_t __weak pcibios_default_alignment(void)
> >  {
> >  	return 0;
> > diff --git a/drivers/pci/search.c b/drivers/pci/search.c
> > index e4dbdef..2061672 100644
> > --- a/drivers/pci/search.c
> > +++ b/drivers/pci/search.c
> > @@ -32,6 +32,12 @@ int pci_for_each_dma_alias(struct pci_dev *pdev,
> >  	struct pci_bus *bus;
> >  	int ret;
> >  
> > +	/*
> > +	 * The device may have an explicit alias requester ID for DMA where the
> > +	 * requester is on another PCI bus.
> > +	 */
> > +	pdev = pci_real_dma_dev(pdev);
> >  	ret = fn(pdev, pci_dev_id(pdev), data);
> >  	if (ret)
> >  		return ret;
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index 930fab2..3840a54 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -1202,6 +1202,7 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev,
> >  int pci_select_bars(struct pci_dev *dev, unsigned long flags);
> >  bool pci_device_is_present(struct pci_dev *pdev);
> >  void pci_ignore_hotplug(struct pci_dev *dev);
> > +struct pci_dev *pci_real_dma_dev(struct pci_dev *dev);
> >  
> >  int __printf(6, 7) pci_request_irq(struct pci_dev *dev, unsigned int nr,
> >  		irq_handler_t handler, irq_handler_t thread_fn, void *dev_id,
> > -- 
> > 1.8.3.1
> > 

[PATCH v5 4/7] iommu/vt-d: Use pci_real_dma_dev() for mapping

[Jon Derrick]

The PCI device may have a DMA requester on another bus, such as VMD
subdevices needing to use the VMD endpoint. This case requires the real
DMA device when mapping to IOMMU.

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 0c8d81f..72f26e8 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -782,6 +782,8 @@ static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devf
 			return NULL;
 #endif
 
+		pdev = pci_real_dma_dev(pdev);
+
 		/* VFs aren't listed in scope tables; we need to look up
 		 * the PF instead to find the IOMMU. */
 		pf_pdev = pci_physfn(pdev);
@@ -2428,6 +2430,9 @@ static struct dmar_domain *find_domain(struct device *dev)
 		     dev->archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO))
 		return NULL;
 
+	if (dev_is_pci(dev))
+		dev = &pci_real_dma_dev(to_pci_dev(dev))->dev;
+
 	/* No lock here, assumes no domain exit in normal case */
 	info = dev->archdata.iommu;
 	if (likely(info))
-- 
1.8.3.1

Re: [PATCH v5 4/7] iommu/vt-d: Use pci_real_dma_dev() for mapping

[Lu Baolu]

On 1/21/20 9:37 PM, Jon Derrick wrote:
> The PCI device may have a DMA requester on another bus, such as VMD
> subdevices needing to use the VMD endpoint. This case requires the real
> DMA device when mapping to IOMMU.
> 
> Signed-off-by: Jon Derrick<jonathan.derrick@intel.com>

Acked-by: Lu Baolu <baolu.lu@linux.intel.com>

Thanks,
baolu

[PATCH v5 5/7] iommu/vt-d: Remove VMD child device sanity check

[Jon Derrick]

This removes the sanity check required for VMD child devices. The new
pci_real_dma_dev() DMA alias mechanism places them in the same IOMMU
group as the VMD endpoint. Assignment of the group would require
assigning the VMD endpoint, where unbinding the VMD endpoint removes the
child device domain from the hierarchy.

Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
---
 drivers/iommu/intel-iommu.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 72f26e8..7e2c492f 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -774,15 +774,7 @@ static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devf
 	if (dev_is_pci(dev)) {
 		struct pci_dev *pf_pdev;
 
-		pdev = to_pci_dev(dev);
-
-#ifdef CONFIG_X86
-		/* VMD child devices currently cannot be handled individually */
-		if (is_vmd(pdev->bus))
-			return NULL;
-#endif
-
-		pdev = pci_real_dma_dev(pdev);
+		pdev = pci_real_dma_dev(to_pci_dev(dev));
 
 		/* VFs aren't listed in scope tables; we need to look up
 		 * the PF instead to find the IOMMU. */
-- 
1.8.3.1

Re: [PATCH v5 5/7] iommu/vt-d: Remove VMD child device sanity check

[Lu Baolu]

On 1/21/20 9:37 PM, Jon Derrick wrote:
> This removes the sanity check required for VMD child devices. The new
> pci_real_dma_dev() DMA alias mechanism places them in the same IOMMU
> group as the VMD endpoint. Assignment of the group would require
> assigning the VMD endpoint, where unbinding the VMD endpoint removes the
> child device domain from the hierarchy.
> 
> Signed-off-by: Jon Derrick<jonathan.derrick@intel.com>

Acked-by: Lu Baolu <baolu.lu@linux.intel.com>

Thanks,
baolu

[PATCH v5 6/7] PCI: vmd: Stop overriding dma_map_ops

[Jon Derrick]

Devices on the VMD domain use the VMD endpoint's requester ID and have
been relying on the VMD endpoint's DMA operations. The problem with this
was that VMD domain devices would use the VMD endpoint's attributes when
doing DMA and IOMMU mapping. We can be smarter about this by only using
the VMD endpoint when mapping and providing the correct child device's
attributes during DMA operations.

This patch removes the dma_map_ops redirect.

Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
---
 drivers/pci/controller/Kconfig |   1 -
 drivers/pci/controller/vmd.c   | 150 -----------------------------------------
 2 files changed, 151 deletions(-)

diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index 918e283..20bf00f 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -239,7 +239,6 @@ config PCIE_TANGO_SMP8759
 
 config VMD
 	depends on PCI_MSI && X86_64 && SRCU
-	select X86_DEV_DMA_OPS
 	tristate "Intel Volume Management Device Driver"
 	---help---
 	  Adds support for the Intel Volume Management Device (VMD). VMD is a
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index d67ad56..fe1acb0 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -98,9 +98,6 @@ struct vmd_dev {
 	struct irq_domain	*irq_domain;
 	struct pci_bus		*bus;
 	u8			busn_start;
-
-	struct dma_map_ops	dma_ops;
-	struct dma_domain	dma_domain;
 };
 
 static inline struct vmd_dev *vmd_from_bus(struct pci_bus *bus)
@@ -295,151 +292,6 @@ static void vmd_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
 	.chip		= &vmd_msi_controller,
 };
 
-/*
- * VMD replaces the requester ID with its own.  DMA mappings for devices in a
- * VMD domain need to be mapped for the VMD, not the device requiring
- * the mapping.
- */
-static struct device *to_vmd_dev(struct device *dev)
-{
-	struct pci_dev *pdev = to_pci_dev(dev);
-	struct vmd_dev *vmd = vmd_from_bus(pdev->bus);
-
-	return &vmd->dev->dev;
-}
-
-static void *vmd_alloc(struct device *dev, size_t size, dma_addr_t *addr,
-		       gfp_t flag, unsigned long attrs)
-{
-	return dma_alloc_attrs(to_vmd_dev(dev), size, addr, flag, attrs);
-}
-
-static void vmd_free(struct device *dev, size_t size, void *vaddr,
-		     dma_addr_t addr, unsigned long attrs)
-{
-	return dma_free_attrs(to_vmd_dev(dev), size, vaddr, addr, attrs);
-}
-
-static int vmd_mmap(struct device *dev, struct vm_area_struct *vma,
-		    void *cpu_addr, dma_addr_t addr, size_t size,
-		    unsigned long attrs)
-{
-	return dma_mmap_attrs(to_vmd_dev(dev), vma, cpu_addr, addr, size,
-			attrs);
-}
-
-static int vmd_get_sgtable(struct device *dev, struct sg_table *sgt,
-			   void *cpu_addr, dma_addr_t addr, size_t size,
-			   unsigned long attrs)
-{
-	return dma_get_sgtable_attrs(to_vmd_dev(dev), sgt, cpu_addr, addr, size,
-			attrs);
-}
-
-static dma_addr_t vmd_map_page(struct device *dev, struct page *page,
-			       unsigned long offset, size_t size,
-			       enum dma_data_direction dir,
-			       unsigned long attrs)
-{
-	return dma_map_page_attrs(to_vmd_dev(dev), page, offset, size, dir,
-			attrs);
-}
-
-static void vmd_unmap_page(struct device *dev, dma_addr_t addr, size_t size,
-			   enum dma_data_direction dir, unsigned long attrs)
-{
-	dma_unmap_page_attrs(to_vmd_dev(dev), addr, size, dir, attrs);
-}
-
-static int vmd_map_sg(struct device *dev, struct scatterlist *sg, int nents,
-		      enum dma_data_direction dir, unsigned long attrs)
-{
-	return dma_map_sg_attrs(to_vmd_dev(dev), sg, nents, dir, attrs);
-}
-
-static void vmd_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
-			 enum dma_data_direction dir, unsigned long attrs)
-{
-	dma_unmap_sg_attrs(to_vmd_dev(dev), sg, nents, dir, attrs);
-}
-
-static void vmd_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
-				    size_t size, enum dma_data_direction dir)
-{
-	dma_sync_single_for_cpu(to_vmd_dev(dev), addr, size, dir);
-}
-
-static void vmd_sync_single_for_device(struct device *dev, dma_addr_t addr,
-				       size_t size, enum dma_data_direction dir)
-{
-	dma_sync_single_for_device(to_vmd_dev(dev), addr, size, dir);
-}
-
-static void vmd_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
-				int nents, enum dma_data_direction dir)
-{
-	dma_sync_sg_for_cpu(to_vmd_dev(dev), sg, nents, dir);
-}
-
-static void vmd_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
-				   int nents, enum dma_data_direction dir)
-{
-	dma_sync_sg_for_device(to_vmd_dev(dev), sg, nents, dir);
-}
-
-static int vmd_dma_supported(struct device *dev, u64 mask)
-{
-	return dma_supported(to_vmd_dev(dev), mask);
-}
-
-static u64 vmd_get_required_mask(struct device *dev)
-{
-	return dma_get_required_mask(to_vmd_dev(dev));
-}
-
-static void vmd_teardown_dma_ops(struct vmd_dev *vmd)
-{
-	struct dma_domain *domain = &vmd->dma_domain;
-
-	if (get_dma_ops(&vmd->dev->dev))
-		del_dma_domain(domain);
-}
-
-#define ASSIGN_VMD_DMA_OPS(source, dest, fn)	\
-	do {					\
-		if (source->fn)			\
-			dest->fn = vmd_##fn;	\
-	} while (0)
-
-static void vmd_setup_dma_ops(struct vmd_dev *vmd)
-{
-	const struct dma_map_ops *source = get_dma_ops(&vmd->dev->dev);
-	struct dma_map_ops *dest = &vmd->dma_ops;
-	struct dma_domain *domain = &vmd->dma_domain;
-
-	domain->domain_nr = vmd->sysdata.domain;
-	domain->dma_ops = dest;
-
-	if (!source)
-		return;
-	ASSIGN_VMD_DMA_OPS(source, dest, alloc);
-	ASSIGN_VMD_DMA_OPS(source, dest, free);
-	ASSIGN_VMD_DMA_OPS(source, dest, mmap);
-	ASSIGN_VMD_DMA_OPS(source, dest, get_sgtable);
-	ASSIGN_VMD_DMA_OPS(source, dest, map_page);
-	ASSIGN_VMD_DMA_OPS(source, dest, unmap_page);
-	ASSIGN_VMD_DMA_OPS(source, dest, map_sg);
-	ASSIGN_VMD_DMA_OPS(source, dest, unmap_sg);
-	ASSIGN_VMD_DMA_OPS(source, dest, sync_single_for_cpu);
-	ASSIGN_VMD_DMA_OPS(source, dest, sync_single_for_device);
-	ASSIGN_VMD_DMA_OPS(source, dest, sync_sg_for_cpu);
-	ASSIGN_VMD_DMA_OPS(source, dest, sync_sg_for_device);
-	ASSIGN_VMD_DMA_OPS(source, dest, dma_supported);
-	ASSIGN_VMD_DMA_OPS(source, dest, get_required_mask);
-	add_dma_domain(domain);
-}
-#undef ASSIGN_VMD_DMA_OPS
-
 static char __iomem *vmd_cfg_addr(struct vmd_dev *vmd, struct pci_bus *bus,
 				  unsigned int devfn, int reg, int len)
 {
@@ -709,7 +561,6 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
 	}
 
 	vmd_attach_resources(vmd);
-	vmd_setup_dma_ops(vmd);
 	dev_set_msi_domain(&vmd->bus->dev, vmd->irq_domain);
 
 	pci_scan_child_bus(vmd->bus);
@@ -824,7 +675,6 @@ static void vmd_remove(struct pci_dev *dev)
 	pci_stop_root_bus(vmd->bus);
 	pci_remove_root_bus(vmd->bus);
 	vmd_cleanup_srcu(vmd);
-	vmd_teardown_dma_ops(vmd);
 	vmd_detach_resources(vmd);
 	irq_domain_remove(vmd->irq_domain);
 }
-- 
1.8.3.1

Re: [PATCH v5 6/7] PCI: vmd: Stop overriding dma_map_ops

[Keith Busch]

On Tue, Jan 21, 2020 at 06:37:50AM -0700, Jon Derrick wrote:
> Devices on the VMD domain use the VMD endpoint's requester ID and have
> been relying on the VMD endpoint's DMA operations. The problem with this
> was that VMD domain devices would use the VMD endpoint's attributes when
> doing DMA and IOMMU mapping. We can be smarter about this by only using
> the VMD endpoint when mapping and providing the correct child device's
> attributes during DMA operations.
> 
> This patch removes the dma_map_ops redirect.
> 
> Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>

Looks good.

Reviewed-by: Keith Busch <kbusch@kernel.org>

[PATCH v5 7/7] x86/PCI: Remove X86_DEV_DMA_OPS

[Jon Derrick]

From: Christoph Hellwig <hch@lst.de>

There are no users of X86_DEV_DMA_OPS left, so remove the code.

Reviewed-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/x86/Kconfig              |  3 ---
 arch/x86/include/asm/device.h | 10 ----------
 arch/x86/pci/common.c         | 38 --------------------------------------
 3 files changed, 51 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5e89499..77f9426 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2955,9 +2955,6 @@ config HAVE_ATOMIC_IOMAP
 	def_bool y
 	depends on X86_32
 
-config X86_DEV_DMA_OPS
-	bool
-
 source "drivers/firmware/Kconfig"
 
 source "arch/x86/kvm/Kconfig"
diff --git a/arch/x86/include/asm/device.h b/arch/x86/include/asm/device.h
index 5e12c63..7e31f7f 100644
--- a/arch/x86/include/asm/device.h
+++ b/arch/x86/include/asm/device.h
@@ -8,16 +8,6 @@ struct dev_archdata {
 #endif
 };
 
-#if defined(CONFIG_X86_DEV_DMA_OPS) && defined(CONFIG_PCI_DOMAINS)
-struct dma_domain {
-	struct list_head node;
-	const struct dma_map_ops *dma_ops;
-	int domain_nr;
-};
-void add_dma_domain(struct dma_domain *domain);
-void del_dma_domain(struct dma_domain *domain);
-#endif
-
 struct pdev_archdata {
 };
 
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index fe21a5c..df1d959 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -625,43 +625,6 @@ unsigned int pcibios_assign_all_busses(void)
 	return (pci_probe & PCI_ASSIGN_ALL_BUSSES) ? 1 : 0;
 }
 
-#if defined(CONFIG_X86_DEV_DMA_OPS) && defined(CONFIG_PCI_DOMAINS)
-static LIST_HEAD(dma_domain_list);
-static DEFINE_SPINLOCK(dma_domain_list_lock);
-
-void add_dma_domain(struct dma_domain *domain)
-{
-	spin_lock(&dma_domain_list_lock);
-	list_add(&domain->node, &dma_domain_list);
-	spin_unlock(&dma_domain_list_lock);
-}
-EXPORT_SYMBOL_GPL(add_dma_domain);
-
-void del_dma_domain(struct dma_domain *domain)
-{
-	spin_lock(&dma_domain_list_lock);
-	list_del(&domain->node);
-	spin_unlock(&dma_domain_list_lock);
-}
-EXPORT_SYMBOL_GPL(del_dma_domain);
-
-static void set_dma_domain_ops(struct pci_dev *pdev)
-{
-	struct dma_domain *domain;
-
-	spin_lock(&dma_domain_list_lock);
-	list_for_each_entry(domain, &dma_domain_list, node) {
-		if (pci_domain_nr(pdev->bus) == domain->domain_nr) {
-			pdev->dev.dma_ops = domain->dma_ops;
-			break;
-		}
-	}
-	spin_unlock(&dma_domain_list_lock);
-}
-#else
-static void set_dma_domain_ops(struct pci_dev *pdev) {}
-#endif
-
 static void set_dev_domain_options(struct pci_dev *pdev)
 {
 	if (is_vmd(pdev->bus))
@@ -697,7 +660,6 @@ int pcibios_add_device(struct pci_dev *dev)
 		pa_data = data->next;
 		memunmap(data);
 	}
-	set_dma_domain_ops(dev);
 	set_dev_domain_options(dev);
 	return 0;
 }
-- 
1.8.3.1

Re: [PATCH v5 0/7] Clean up VMD DMA Map Ops

[Bjorn Helgaas]

On Tue, Jan 21, 2020 at 06:37:44AM -0700, Jon Derrick wrote:
> v4 Set: https://lore.kernel.org/linux-pci/20200120110220.GB17267@e121166-lin.cambridge.arm.com/T/#t
> v3 Set: https://lore.kernel.org/linux-iommu/20200113181742.GA27623@e121166-lin.cambridge.arm.com/T/#t
> v2 Set: https://lore.kernel.org/linux-iommu/1578580256-3483-1-git-send-email-jonathan.derrick@intel.com/T/#t
> v1 Set: https://lore.kernel.org/linux-iommu/20200107134125.GD30750@8bytes.org/T/#t
> 
> VMD currently works with VT-d enabled by pointing DMA and IOMMU actions at the
> VMD endpoint. The problem with this approach is that the VMD endpoint's
> device-specific attributes, such as the DMA Mask Bits, are used instead of the
> child device's attributes.
> 
> This set cleans up VMD by removing the override that redirects DMA map
> operations to the VMD endpoint. Instead it introduces a new DMA alias mechanism
> into the existing DMA alias infrastructure. This new DMA alias mechanism allows
> an architecture-specific pci_real_dma_dev() function to provide a pointer from
> a pci_dev to its PCI DMA device, where by default it returns the original
> pci_dev.
> 
> In addition, this set removes the sanity check that was added to prevent
> assigning VMD child devices. By using the DMA alias mechanism, all child
> devices are assigned the same IOMMU group as the VMD endpoint. This removes the
> need for restricting VMD child devices from assignment, as the whole group
> would have to be assigned, requiring unbinding the VMD driver and removing the
> child device domain.
> 
> v1 added a pointer in struct pci_dev that pointed to the DMA alias' struct
> pci_dev and did the necessary DMA alias and IOMMU modifications.
> 
> v2 introduced a new weak function to reference the 'Direct DMA Alias', and
> removed the need to add a pointer in struct device or pci_dev. Weak functions
> are generally frowned upon when it's a single architecture implementation, so I
> am open to alternatives.
> 
> v3 referenced the pci_dev rather than the struct device for the PCI
> 'Direct DMA Alias' (pci_direct_dma_alias()). This revision also allowed
> pci_for_each_dma_alias() to call any DMA aliases for the Direct DMA alias
> device, though I don't expect the VMD endpoint to need intra-bus DMA aliases.
> 
> v4 changes the 'Direct DMA Alias' to instead refer to the 'Real DMA Dev', which
> either returns the PCI device itself or the PCI DMA device.
> 
> v5 Fixes a bad call argument to pci_real_dma_dev that would have broken
> bisection. This revision also changes one of the calls to a one-liner, and
> assembles the same on my system.
> 
> 
> Changes from v4:
> Fix pci_real_dma_dev() call in 4/7.
> Change other pci_real_dma_dev() call in 4/7 to one-liner.
> 
> Changes from v3:
> Uses pci_real_dma_dev() instead of pci_direct_dma_alias()
> Split IOMMU enabling, IOMMU VMD sanity check and VMD dma_map_ops cleanup into three patches
> 
> Changes from v2:
> Uses struct pci_dev for PCI Device 'Direct DMA aliasing' (pci_direct_dma_alias)
> Allows pci_for_each_dma_alias to iterate over the alias mask of the 'Direct DMA alias'
> 
> Changes from v1:
> Removed 1/5 & 2/5 misc fix patches that were merged
> Uses Christoph's staging/cleanup patches
> Introduce weak function rather than including pointer in struct device or pci_dev.
> 
> Based on Bjorn's next:
> https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git/log/?h=next
> 
> Christoph Hellwig (2):
>   x86/PCI: Add a to_pci_sysdata helper
>   x86/PCI: Remove X86_DEV_DMA_OPS
> 
> Jon Derrick (5):
>   x86/PCI: Expose VMD's PCI Device in pci_sysdata
>   PCI: Introduce pci_real_dma_dev()
>   iommu/vt-d: Use pci_real_dma_dev() for mapping
>   iommu/vt-d: Remove VMD child device sanity check
>   PCI: vmd: Stop overriding dma_map_ops
> 
>  arch/x86/Kconfig               |   3 -
>  arch/x86/include/asm/device.h  |  10 ---
>  arch/x86/include/asm/pci.h     |  31 ++++-----
>  arch/x86/pci/common.c          |  48 +++----------
>  drivers/iommu/intel-iommu.c    |  11 ++-
>  drivers/pci/controller/Kconfig |   1 -
>  drivers/pci/controller/vmd.c   | 152 +----------------------------------------
>  drivers/pci/pci.c              |  19 +++++-
>  drivers/pci/search.c           |   6 ++
>  include/linux/pci.h            |   1 +
>  10 files changed, 54 insertions(+), 228 deletions(-)

Applied with acks/reviewed-by from Lu, Keith, and Lorenzo to
pci/host-vmd for v5.6, thanks!