[PATCH] Quirk to support Marvell 88SE91xx SATA controllers with Intel IOMMU.

[Andrew Cooks <acooks@gmail.com>]

This is my third submitted patch to make Marvell 88SE91xx SATA controllers work when IOMMU is enabled.[1][2]

What's changed:
* Adopt David Woodhouse's terminology by referring to the quirky functions as 'ghost' functions.
* Unmap ghost functions when device is detached from IOMMU.
* Stub function for when CONFIG_PCI_QUIRKS is not enabled.

The bad:
* Still no AMD support.
* The table of affected chip IDs is as complete as I can make it by googling for bug reports.

This patch was generated against commit b0af9cd9aab60ceb17d3ebabb9fdf4ff0a99cf50, but will also apply cleanly to 3.7.10.

Bug reports:
1. https://bugzilla.redhat.com/show_bug.cgi?id=757166
2. https://bugzilla.kernel.org/show_bug.cgi?id=42679

Signed-off-by: Andrew Cooks <acooks@gmail.com>
---
 drivers/iommu/intel-iommu.c |   50 +++++++++++++++++++++++++++++++++++++++++++
 drivers/pci/quirks.c        |   47 +++++++++++++++++++++++++++++++++++++++-
 include/linux/pci.h         |    5 ++++
 include/linux/pci_ids.h     |    1 +
 4 files changed, 102 insertions(+), 1 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 0099667..13323f2 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1674,6 +1674,50 @@ static int domain_context_mapping_one(struct dmar_domain *domain, int segment,
 	return 0;
 }
 
+/* For quirky devices like Marvell 88SE91xx chips that use ghost functions. */
+static int map_ghost_dma_fn(struct dmar_domain *domain,
+		struct pci_dev *pdev,
+		int translation)
+{
+	u8 fn, fn_map;
+	int err = 0;
+
+	fn_map = pci_get_dma_source_map(pdev);
+
+	for (fn = 1; fn < 8; fn++) {
+		if (fn_map & (1 << fn)) {
+			err = domain_context_mapping_one(domain,
+					pci_domain_nr(pdev->bus),
+					pdev->bus->number,
+					PCI_DEVFN(PCI_SLOT(pdev->devfn), fn),
+					translation);
+			if (err)
+				return err;
+			dev_dbg(&pdev->dev, "dma quirk; func %d mapped", fn);
+		}
+	}
+	return 0;
+}
+
+static void iommu_detach_dev(struct intel_iommu *iommu, u8 bus, u8 devfn);
+
+static void unmap_ghost_dma_fn(struct intel_iommu *iommu,
+		struct pci_dev *pdev)
+{
+	u8 fn, fn_map;
+
+	fn_map = pci_get_dma_source_map(pdev);
+
+	for (fn = 1; fn < 8; fn++) {
+		if (fn_map & (1 << fn)) {
+			iommu_detach_dev(iommu,
+					pdev->bus->number,
+					PCI_DEVFN(PCI_SLOT(pdev->devfn), fn));
+			dev_dbg(&pdev->dev, "dma quirk; func %d unmapped", fn);
+		}
+	}
+}
+
 static int
 domain_context_mapping(struct dmar_domain *domain, struct pci_dev *pdev,
 			int translation)
@@ -1687,6 +1731,11 @@ domain_context_mapping(struct dmar_domain *domain, struct pci_dev *pdev,
 	if (ret)
 		return ret;
 
+	/* quirk for undeclared/ghost pci functions */
+	ret = map_ghost_dma_fn(domain, pdev, translation);
+	if (ret)
+		return ret;
+
 	/* dependent device mapping */
 	tmp = pci_find_upstream_pcie_bridge(pdev);
 	if (!tmp)
@@ -3786,6 +3835,7 @@ static void domain_remove_one_dev_info(struct dmar_domain *domain,
 			iommu_disable_dev_iotlb(info);
 			iommu_detach_dev(iommu, info->bus, info->devfn);
 			iommu_detach_dependent_devices(iommu, pdev);
+			unmap_ghost_dma_fn(iommu, pdev);
 			free_devinfo_mem(info);
 
 			spin_lock_irqsave(&device_domain_lock, flags);
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 0369fb6..d311100 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3249,6 +3249,10 @@ static struct pci_dev *pci_func_0_dma_source(struct pci_dev *dev)
 	return pci_get_slot(dev->bus, PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
 }
 
+/* Table of source functions for real devices. The DMA requests for the
+ * device are tagged with a different real function as source. This is
+ * relevant to multifunction devices.
+ */
 static const struct pci_dev_dma_source {
 	u16 vendor;
 	u16 device;
@@ -3275,7 +3279,8 @@ static const struct pci_dev_dma_source {
  * the device doing the DMA, but sometimes hardware is broken and will
  * tag the DMA as being sourced from a different device.  This function
  * allows that translation.  Note that the reference count of the
- * returned device is incremented on all paths.
+ * returned device is incremented on all paths. Translation is done when
+ * the device is added to an IOMMU group.
  */
 struct pci_dev *pci_get_dma_source(struct pci_dev *dev)
 {
@@ -3292,6 +3297,46 @@ struct pci_dev *pci_get_dma_source(struct pci_dev *dev)
 	return pci_dev_get(dev);
 }
 
+/* Table of multiple (ghost) source functions. This is similar to the
+ * translated sources above, but with the following differences:
+ * 1. the device may use multiple functions as DMA sources,
+ * 2. these functions cannot be assumed to be actual devices,
+ * 3. the specific ghost function for a request can not be exactly predicted.
+ * The bitmap only contains the additional quirk functions.
+ */
+static const struct pci_dev_dma_multi_func_sources {
+	u16 vendor;
+	u16 device;
+	u8 func_map;	/* bit map. lsb is fn 0. */
+} pci_dev_dma_multi_func_sources[] = {
+	{ PCI_VENDOR_ID_MARVELL_2, 0x9123, (1<<0)|(1<<1)},
+	{ PCI_VENDOR_ID_MARVELL_2, 0x9125, (1<<0)|(1<<1)},
+	{ PCI_VENDOR_ID_MARVELL_2, 0x9128, (1<<0)|(1<<1)},
+	{ PCI_VENDOR_ID_MARVELL_2, 0x9130, (1<<0)|(1<<1)},
+	{ PCI_VENDOR_ID_MARVELL_2, 0x9172, (1<<0)|(1<<1)},
+	{ 0 }
+};
+
+/*
+ * The mapping of fake/ghost functions is used when the real device is
+ * attached to an IOMMU domain. IOMMU groups are not aware of these
+ * functions, because they're not real devices.
+ */
+u8 pci_get_dma_source_map(struct pci_dev *dev)
+{
+	const struct pci_dev_dma_multi_func_sources *i;
+
+	for (i = pci_dev_dma_multi_func_sources; i->func_map; i++) {
+		if ((i->vendor == dev->vendor ||
+		     i->vendor == (u16)PCI_ANY_ID) &&
+		    (i->device == dev->device ||
+		     i->device == (u16)PCI_ANY_ID)) {
+			return i->func_map;
+		}
+	}
+	return 0;
+}
+
 static const struct pci_dev_acs_enabled {
 	u16 vendor;
 	u16 device;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 2461033..5ad3822 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1578,6 +1578,7 @@ enum pci_fixup_pass {
 #ifdef CONFIG_PCI_QUIRKS
 void pci_fixup_device(enum pci_fixup_pass pass, struct pci_dev *dev);
 struct pci_dev *pci_get_dma_source(struct pci_dev *dev);
+u8 pci_get_dma_source_map(struct pci_dev *dev);
 int pci_dev_specific_acs_enabled(struct pci_dev *dev, u16 acs_flags);
 #else
 static inline void pci_fixup_device(enum pci_fixup_pass pass,
@@ -1586,6 +1587,10 @@ static inline struct pci_dev *pci_get_dma_source(struct pci_dev *dev)
 {
 	return pci_dev_get(dev);
 }
+u8 pci_get_dma_source_map(struct pci_dev *dev)
+{
+	return 0;
+}
 static inline int pci_dev_specific_acs_enabled(struct pci_dev *dev,
 					       u16 acs_flags)
 {
diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
index f11c1c2..df57496 100644
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -1604,6 +1604,7 @@
 #define PCI_SUBDEVICE_ID_KEYSPAN_SX2	0x5334
 
 #define PCI_VENDOR_ID_MARVELL		0x11ab
+#define PCI_VENDOR_ID_MARVELL_2	0x1b4b
 #define PCI_DEVICE_ID_MARVELL_GT64111	0x4146
 #define PCI_DEVICE_ID_MARVELL_GT64260	0x6430
 #define PCI_DEVICE_ID_MARVELL_MV64360	0x6460
-- 
1.7.1