Re: [PATCH 4/7 v2] pseries/iommu: implement DDW-aware dma_get_page_shift

[Nishanth Aravamudan]

On 27.10.2015 [16:56:10 +1100], Alexey Kardashevskiy wrote:
> On 10/24/2015 07:59 AM, Nishanth Aravamudan wrote:
> >When DDW (Dynamic DMA Windows) are present for a device, we have stored
> >the TCE (Translation Control Entry) size in a special device tree
> >property. Check if we have enabled DDW for the device and return the TCE
> >size from that property if present. If the property isn't present,
> >fallback to looking the value up in struct iommu_table. If we don't find
> >a iommu_table, fallback to the kernel's page size.
> >
> >Signed-off-by: Nishanth Aravamudan 
> >---
> >  arch/powerpc/platforms/pseries/iommu.c | 36 
> > ++
> >  1 file changed, 36 insertions(+)
> >
> >diff --git a/arch/powerpc/platforms/pseries/iommu.c 
> >b/arch/powerpc/platforms/pseries/iommu.c
> >index 0946b98..1bf6471 100644
> >--- a/arch/powerpc/platforms/pseries/iommu.c
> >+++ b/arch/powerpc/platforms/pseries/iommu.c
> >@@ -1292,6 +1292,40 @@ static u64 dma_get_required_mask_pSeriesLP(struct 
> >device *dev)
> > return dma_iommu_ops.get_required_mask(dev);
> >  }
> >
> >+static unsigned long dma_get_page_shift_pSeriesLP(struct device *dev)
> >+{
> >+struct iommu_table *tbl;
> >+
> >+if (!disable_ddw && dev_is_pci(dev)) {
> >+struct pci_dev *pdev = to_pci_dev(dev);
> >+struct device_node *dn;
> >+
> >+dn = pci_device_to_OF_node(pdev);
> >+
> >+/* search upwards for ibm,dma-window */
> >+for (; dn && PCI_DN(dn) && !PCI_DN(dn)->table_group;
> >+dn = dn->parent)
> >+if (of_get_property(dn, "ibm,dma-window", NULL))
> >+break;
> >+/*
> >+ * if there is a DDW configuration, the TCE shift is stored in
> >+ * the property
> >+ */
> >+if (dn && PCI_DN(dn)) {
> >+const struct dynamic_dma_window_prop *direct64 =
> >+of_get_property(dn, DIRECT64_PROPNAME, NULL);
> 
> 
> This DIRECT64_PROPNAME property is only present under pHyp, QEMU/KVM
> does not set it as 64bit windows are dynamic there so something like
> find_existing_ddw() needs to be used here.

DIRECT64_PROPNAME is a Linux thing, not a pHyp or QEMU/KVM thing -- it's
created by the Linux DDW logic and left in the device-tree when we
successfully configure DDW.

You're right, though, that logically find_existing_ddw() would be better
to use here. I'll spin up a new version.

-Nish

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Re: [PATCH 4/7 v2] pseries/iommu: implement DDW-aware dma_get_page_shift

[Alexey Kardashevskiy]

On 10/24/2015 07:59 AM, Nishanth Aravamudan wrote:

When DDW (Dynamic DMA Windows) are present for a device, we have stored
the TCE (Translation Control Entry) size in a special device tree
property. Check if we have enabled DDW for the device and return the TCE
size from that property if present. If the property isn't present,
fallback to looking the value up in struct iommu_table. If we don't find
a iommu_table, fallback to the kernel's page size.

Signed-off-by: Nishanth Aravamudan 
---
  arch/powerpc/platforms/pseries/iommu.c | 36 ++
  1 file changed, 36 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/iommu.c 
b/arch/powerpc/platforms/pseries/iommu.c
index 0946b98..1bf6471 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -1292,6 +1292,40 @@ static u64 dma_get_required_mask_pSeriesLP(struct device 
*dev)
return dma_iommu_ops.get_required_mask(dev);
  }

+static unsigned long dma_get_page_shift_pSeriesLP(struct device *dev)
+{
+   struct iommu_table *tbl;
+
+   if (!disable_ddw && dev_is_pci(dev)) {
+   struct pci_dev *pdev = to_pci_dev(dev);
+   struct device_node *dn;
+
+   dn = pci_device_to_OF_node(pdev);
+
+   /* search upwards for ibm,dma-window */
+   for (; dn && PCI_DN(dn) && !PCI_DN(dn)->table_group;
+   dn = dn->parent)
+   if (of_get_property(dn, "ibm,dma-window", NULL))
+   break;
+   /*
+* if there is a DDW configuration, the TCE shift is stored in
+* the property
+*/
+   if (dn && PCI_DN(dn)) {
+   const struct dynamic_dma_window_prop *direct64 =
+   of_get_property(dn, DIRECT64_PROPNAME, NULL);



This DIRECT64_PROPNAME property is only present under pHyp, QEMU/KVM does 
not set it as 64bit windows are dynamic there so something like 
find_existing_ddw() needs to be used here.





+   if (direct64)
+   return be32_to_cpu(direct64->tce_shift);
+   }
+   }
+
+   tbl = get_iommu_table_base(dev);
+   if (tbl)
+   return tbl->it_page_shift;
+
+   return PAGE_SHIFT;
+}
+
  #else  /* CONFIG_PCI */
  #define pci_dma_bus_setup_pSeries NULL
  #define pci_dma_dev_setup_pSeries NULL
@@ -1299,6 +1333,7 @@ static u64 dma_get_required_mask_pSeriesLP(struct device 
*dev)
  #define pci_dma_dev_setup_pSeriesLP   NULL
  #define dma_set_mask_pSeriesLPNULL
  #define dma_get_required_mask_pSeriesLP   NULL
+#define dma_get_page_shift_pSeriesLP   NULL
  #endif /* !CONFIG_PCI */

  static int iommu_mem_notifier(struct notifier_block *nb, unsigned long action,
@@ -1395,6 +1430,7 @@ void iommu_init_early_pSeries(void)
pseries_pci_controller_ops.dma_dev_setup = 
pci_dma_dev_setup_pSeriesLP;
ppc_md.dma_set_mask = dma_set_mask_pSeriesLP;
ppc_md.dma_get_required_mask = dma_get_required_mask_pSeriesLP;
+   ppc_md.dma_get_page_shift = dma_get_page_shift_pSeriesLP;
} else {
pseries_pci_controller_ops.dma_bus_setup = 
pci_dma_bus_setup_pSeries;
pseries_pci_controller_ops.dma_dev_setup = 
pci_dma_dev_setup_pSeries;




--
Alexey
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[PATCH 4/7 v2] pseries/iommu: implement DDW-aware dma_get_page_shift

[Nishanth Aravamudan]

When DDW (Dynamic DMA Windows) are present for a device, we have stored
the TCE (Translation Control Entry) size in a special device tree
property. Check if we have enabled DDW for the device and return the TCE
size from that property if present. If the property isn't present,
fallback to looking the value up in struct iommu_table. If we don't find
a iommu_table, fallback to the kernel's page size.

Signed-off-by: Nishanth Aravamudan 
---
 arch/powerpc/platforms/pseries/iommu.c | 36 ++
 1 file changed, 36 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/iommu.c 
b/arch/powerpc/platforms/pseries/iommu.c
index 0946b98..1bf6471 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -1292,6 +1292,40 @@ static u64 dma_get_required_mask_pSeriesLP(struct device 
*dev)
return dma_iommu_ops.get_required_mask(dev);
 }
 
+static unsigned long dma_get_page_shift_pSeriesLP(struct device *dev)
+{
+   struct iommu_table *tbl;
+
+   if (!disable_ddw && dev_is_pci(dev)) {
+   struct pci_dev *pdev = to_pci_dev(dev);
+   struct device_node *dn;
+
+   dn = pci_device_to_OF_node(pdev);
+
+   /* search upwards for ibm,dma-window */
+   for (; dn && PCI_DN(dn) && !PCI_DN(dn)->table_group;
+   dn = dn->parent)
+   if (of_get_property(dn, "ibm,dma-window", NULL))
+   break;
+   /*
+* if there is a DDW configuration, the TCE shift is stored in
+* the property
+*/
+   if (dn && PCI_DN(dn)) {
+   const struct dynamic_dma_window_prop *direct64 =
+   of_get_property(dn, DIRECT64_PROPNAME, NULL);
+   if (direct64)
+   return be32_to_cpu(direct64->tce_shift);
+   }
+   }
+
+   tbl = get_iommu_table_base(dev);
+   if (tbl)
+   return tbl->it_page_shift;
+
+   return PAGE_SHIFT;
+}
+
 #else  /* CONFIG_PCI */
 #define pci_dma_bus_setup_pSeries  NULL
 #define pci_dma_dev_setup_pSeries  NULL
@@ -1299,6 +1333,7 @@ static u64 dma_get_required_mask_pSeriesLP(struct device 
*dev)
 #define pci_dma_dev_setup_pSeriesLPNULL
 #define dma_set_mask_pSeriesLP NULL
 #define dma_get_required_mask_pSeriesLPNULL
+#define dma_get_page_shift_pSeriesLP   NULL
 #endif /* !CONFIG_PCI */
 
 static int iommu_mem_notifier(struct notifier_block *nb, unsigned long action,
@@ -1395,6 +1430,7 @@ void iommu_init_early_pSeries(void)
pseries_pci_controller_ops.dma_dev_setup = 
pci_dma_dev_setup_pSeriesLP;
ppc_md.dma_set_mask = dma_set_mask_pSeriesLP;
ppc_md.dma_get_required_mask = dma_get_required_mask_pSeriesLP;
+   ppc_md.dma_get_page_shift = dma_get_page_shift_pSeriesLP;
} else {
pseries_pci_controller_ops.dma_bus_setup = 
pci_dma_bus_setup_pSeries;
pseries_pci_controller_ops.dma_dev_setup = 
pci_dma_dev_setup_pSeries;
-- 
1.9.1

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