Intel IOMMU: Iommu floppy workaround (49a0429e) · Commits · 戴 / test

This config option (DMAR_FLPY_WA) sets up 1:1 mapping for the floppy device so that the floppy device which does not use DMA api's will continue to work. Once the floppy driver starts using DMA api's this config option can be turn off or this patch can be yanked out of kernel at that time. [akpm@linux-foundation.org: cleanups, rename things, build fix] [jengelh@computergmbh.de: Kconfig fixes] Signed-off-by:

Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Muli Ben-Yehuda <muli@il.ibm.com> Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Ashok Raj <ashok.raj@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Christoph Lameter <clameter@sgi.com> Cc: Greg KH <greg@kroah.com> Signed-off-by:

Jan Engelhardt <jengelh@gmx.de> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

arch/x86_64/Kconfig

+10 −0

Original line number	Diff line number	Diff line
		@@ -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"

drivers/pci/intel-iommu.c

+27 −0

Original line number	Diff line number	Diff line
		@@ -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, 1610241024);

		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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