Commit 5448c155 authored by Jason Gunthorpe's avatar Jason Gunthorpe Committed by Joerg Roedel
Browse files

iommupt: Add the Intel VT-d second stage page table format 



The VT-d second stage format is almost the same as the x86 PAE format,
except the bit encodings in the PTE are different and a few new PTE
features, like force coherency are present.

Among all the formats it is unique in not having a designated present bit.

Comparing the performance of several operations to the existing version:

iommu_map()
   pgsz  ,avg new,old ns, min new,old ns  , min % (+ve is better)
     2^12,     53,66    ,      50,64      ,  21.21
     2^21,     59,70    ,      56,67      ,  16.16
     2^30,     54,66    ,      52,63      ,  17.17
 256*2^12,    384,524   ,     337,516     ,  34.34
 256*2^21,    387,632   ,     336,626     ,  46.46
 256*2^30,    376,629   ,     323,623     ,  48.48

iommu_unmap()
   pgsz  ,avg new,old ns, min new,old ns  , min % (+ve is better)
     2^12,     67,86    ,      63,84      ,  25.25
     2^21,     64,84    ,      59,80      ,  26.26
     2^30,     59,78    ,      56,74      ,  24.24
 256*2^12,    216,335   ,     198,317     ,  37.37
 256*2^21,    245,350   ,     232,344     ,  32.32
 256*2^30,    248,345   ,     226,339     ,  33.33

Cc: Tina Zhang <tina.zhang@intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
parent efa03dab

drivers/iommu/generic_pt/.kunitconfig

+1 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ CONFIG_GENERIC_PT=y 
CONFIG_DEBUG_GENERIC_PT=y

CONFIG_IOMMU_PT=y

CONFIG_IOMMU_PT_AMDV1=y

CONFIG_IOMMU_PT_VTDSS=y

CONFIG_IOMMU_PT_X86_64=y

CONFIG_IOMMU_PT_KUNIT_TEST=y

drivers/iommu/generic_pt/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -42,6 +42,16 @@ config IOMMU_PT_AMDV1 


	  Selected automatically by an IOMMU driver that uses this format.



config IOMMU_PT_VTDSS

       tristate "IOMMU page table for Intel VT-d Second Stage"

	depends on !GENERIC_ATOMIC64 # for cmpxchg64

	help

	  iommu_domain implementation for the Intel VT-d's 64 bit 3/4/5

	  level Second Stage page table. It is similar to the X86_64 format with

	  4K/2M/1G page sizes.



	  Selected automatically by an IOMMU driver that uses this format.



config IOMMU_PT_X86_64

	tristate "IOMMU page table for x86 64-bit, 4/5 levels"

	depends on !GENERIC_ATOMIC64 # for cmpxchg64
@@ -57,6 +67,7 @@ config IOMMU_PT_KUNIT_TEST 
	depends on KUNIT

	depends on IOMMU_PT_AMDV1 || !IOMMU_PT_AMDV1

	depends on IOMMU_PT_X86_64 || !IOMMU_PT_X86_64

	depends on IOMMU_PT_VTDSS || !IOMMU_PT_VTDSS

	default KUNIT_ALL_TESTS

	help

	  Enable kunit tests for GENERIC_PT and IOMMU_PT that covers all the

drivers/iommu/generic_pt/fmt/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -3,6 +3,8 @@ 
iommu_pt_fmt-$(CONFIG_IOMMU_PT_AMDV1) += amdv1

iommu_pt_fmt-$(CONFIG_IOMMUFD_TEST) += mock



iommu_pt_fmt-$(CONFIG_IOMMU_PT_VTDSS) += vtdss



iommu_pt_fmt-$(CONFIG_IOMMU_PT_X86_64) += x86_64



IOMMU_PT_KUNIT_TEST :=

drivers/iommu/generic_pt/fmt/defs_vtdss.h

0 → 100644
+21 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES

 *

 */

#ifndef __GENERIC_PT_FMT_DEFS_VTDSS_H

#define __GENERIC_PT_FMT_DEFS_VTDSS_H



#include <linux/generic_pt/common.h>

#include <linux/types.h>



typedef u64 pt_vaddr_t;

typedef u64 pt_oaddr_t;



struct vtdss_pt_write_attrs {

	u64 descriptor_bits;

	gfp_t gfp;

};

#define pt_write_attrs vtdss_pt_write_attrs



#endif

drivers/iommu/generic_pt/fmt/iommu_vtdss.c

0 → 100644
+10 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES

 */

#define PT_FMT vtdss

#define PT_SUPPORTED_FEATURES                                            \

	(BIT(PT_FEAT_FLUSH_RANGE) | BIT(PT_FEAT_VTDSS_FORCE_COHERENCE) | \

	 BIT(PT_FEAT_VTDSS_FORCE_WRITEABLE) | BIT(PT_FEAT_DMA_INCOHERENT))



#include "iommu_template.h"