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-rw-r--r--arch/x86_64/Kconfig10
-rw-r--r--drivers/pci/intel-iommu.c27
2 files changed, 37 insertions, 0 deletions
diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index 5cf9417..c2d2499 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -772,6 +772,16 @@ config DMAR_GFX_WA
all the OS-visible memory. Hence the driver can continue
to use physical addresses for DMA.
+config DMAR_FLOPPY_WA
+ bool
+ depends on DMAR
+ default y
+ help
+ Floppy disk drivers are know to bypass DMA API calls
+ thereby failing to work when IOMMU is enabled. This
+ workaround will setup a 1:1 mapping for the first
+ 16M to make floppy (an ISA device) work.
+
source "drivers/pci/pcie/Kconfig"
source "drivers/pci/Kconfig"
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 4905e0e..4cca5b9 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -1632,6 +1632,31 @@ error:
}
#endif
+#ifdef CONFIG_DMAR_FLOPPY_WA
+static inline void iommu_prepare_isa(void)
+{
+ struct pci_dev *pdev;
+ int ret;
+
+ pdev = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, NULL);
+ if (!pdev)
+ return;
+
+ printk(KERN_INFO "IOMMU: Prepare 0-16M unity mapping for LPC\n");
+ ret = iommu_prepare_identity_map(pdev, 0, 16*1024*1024);
+
+ if (ret)
+ printk("IOMMU: Failed to create 0-64M identity map, "
+ "floppy might not work\n");
+
+}
+#else
+static inline void iommu_prepare_isa(void)
+{
+ return;
+}
+#endif /* !CONFIG_DMAR_FLPY_WA */
+
int __init init_dmars(void)
{
struct dmar_drhd_unit *drhd;
@@ -1697,6 +1722,8 @@ int __init init_dmars(void)
iommu_prepare_gfx_mapping();
+ iommu_prepare_isa();
+
/*
* for each drhd
* enable fault log
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