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Commit e820482c authored by Keshavamurthy, Anil S's avatar Keshavamurthy, Anil S Committed by Linus Torvalds
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Intel IOMMU: Iommu Gfx workaround 



When we fix all the opensource gfx drivers to use the DMA api's, at that time
we can yank this config options out.

[jengelh@computergmbh.de: Kconfig fixes]
Signed-off-by: default avatarAnil 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: default avatarJan Engelhardt <jengelh@gmx.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3460a6d9

Documentation/Intel-IOMMU.txt

+5 −0
Original line number Diff line number Diff line
@@ -57,6 +57,11 @@ Graphics Problems? 
If you encounter issues with graphics devices, you can try adding

option intel_iommu=igfx_off to turn off the integrated graphics engine.



If it happens to be a PCI device included in the INCLUDE_ALL Engine,

then try enabling CONFIG_DMAR_GFX_WA to setup a 1-1 map. We hear

graphics drivers may be in process of using DMA api's in the near

future and at that time this option can be yanked out.



Some exceptions to IOVA

-----------------------

Interrupt ranges are not address translated, (0xfee00000 - 0xfeefffff).

arch/x86/kernel/e820_64.c

+19 −0
Original line number Diff line number Diff line
@@ -729,3 +729,22 @@ __init void e820_setup_gap(void) 
	printk(KERN_INFO "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",

		pci_mem_start, gapstart, gapsize);

}



int __init arch_get_ram_range(int slot, u64 *addr, u64 *size)

{

	int i;



	if (slot < 0 || slot >= e820.nr_map)

		return -1;

	for (i = slot; i < e820.nr_map; i++) {

		if (e820.map[i].type != E820_RAM)

			continue;

		break;

	}

	if (i == e820.nr_map || e820.map[i].addr > (max_pfn << PAGE_SHIFT))

		return -1;

	*addr = e820.map[i].addr;

	*size = min_t(u64, e820.map[i].size + e820.map[i].addr,

		max_pfn << PAGE_SHIFT) - *addr;

	return i + 1;

}

arch/x86_64/Kconfig

+15 −4
Original line number Diff line number Diff line
@@ -756,10 +756,21 @@ config DMAR 
	default y

	help

	  DMA remapping (DMAR) devices support enables independent address

	  translations for Direct Memory Access(DMA) from Devices.

	  translations for Direct Memory Access (DMA) from devices.

	  These DMA remapping devices are reported via ACPI tables

	  and includes pci device scope covered by these DMA

	  remapping device.

	  and include PCI device scope covered by these DMA

	  remapping devices.



config DMAR_GFX_WA

	bool "Support for Graphics workaround"

	depends on DMAR

	default y

	help

	 Current Graphics drivers tend to use physical address

	 for DMA and avoid using DMA APIs. Setting this config

	 option permits the IOMMU driver to set a unity map for

	 all the OS-visible memory. Hence the driver can continue

	 to use physical addresses for DMA.



source "drivers/pci/pcie/Kconfig"

drivers/pci/intel-iommu.c

+33 −0
Original line number Diff line number Diff line
@@ -1602,6 +1602,36 @@ static inline int iommu_prepare_rmrr_dev(struct dmar_rmrr_unit *rmrr, 
		rmrr->end_address + 1);

}



#ifdef CONFIG_DMAR_GFX_WA

extern int arch_get_ram_range(int slot, u64 *addr, u64 *size);

static void __init iommu_prepare_gfx_mapping(void)

{

	struct pci_dev *pdev = NULL;

	u64 base, size;

	int slot;

	int ret;



	for_each_pci_dev(pdev) {

		if (pdev->sysdata == DUMMY_DEVICE_DOMAIN_INFO ||

				!IS_GFX_DEVICE(pdev))

			continue;

		printk(KERN_INFO "IOMMU: gfx device %s 1-1 mapping\n",

			pci_name(pdev));

		slot = arch_get_ram_range(0, &base, &size);

		while (slot >= 0) {

			ret = iommu_prepare_identity_map(pdev,

					base, base + size);

			if (ret)

				goto error;

			slot = arch_get_ram_range(slot, &base, &size);

		}

		continue;

error:

		printk(KERN_ERR "IOMMU: mapping reserved region failed\n");

	}

}

#endif



int __init init_dmars(void)

{

	struct dmar_drhd_unit *drhd;
@@ -1665,6 +1695,8 @@ int __init init_dmars(void) 
		}

	}



	iommu_prepare_gfx_mapping();



	/*

	 * for each drhd

	 *   enable fault log
@@ -2176,3 +2208,4 @@ int __init intel_iommu_init(void) 
	dma_ops = &intel_dma_ops;

	return 0;

}

drivers/pci/intel-iommu.h

+7 −0
Original line number Diff line number Diff line
@@ -315,4 +315,11 @@ struct intel_iommu { 
	struct sys_device sysdev;

};



#ifndef CONFIG_DMAR_GFX_WA

static inline void iommu_prepare_gfx_mapping(void)

{

	return;

}

#endif /* !CONFIG_DMAR_GFX_WA */



#endif