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alistair23-linux/include/linux/dmar.h
Lu Baolu 89a6079df7 iommu/vt-d: Force IOMMU on for platform opt in hint 
Intel VT-d spec added a new DMA_CTRL_PLATFORM_OPT_IN_FLAG flag in DMAR
ACPI table [1] for BIOS to report compliance about platform initiated
DMA restricted to RMRR ranges when transferring control to the OS. This
means that during OS boot, before it enables IOMMU none of the connected
devices can bypass DMA protection for instance by overwriting the data
structures used by the IOMMU. The OS also treats this as a hint that the
IOMMU should be enabled to prevent DMA attacks from possible malicious
devices.

A use of this flag is Kernel DMA protection for Thunderbolt [2] which in
practice means that IOMMU should be enabled for PCIe devices connected
to the Thunderbolt ports. With IOMMU enabled for these devices, all DMA
operations are limited in the range reserved for it, thus the DMA
attacks are prevented. All these devices are enumerated in the PCI/PCIe
module and marked with an untrusted flag.

This forces IOMMU to be enabled if DMA_CTRL_PLATFORM_OPT_IN_FLAG is set
in DMAR ACPI table and there are PCIe devices marked as untrusted in the
system. This can be turned off by adding "intel_iommu=off" in the kernel
command line, if any problems are found.

[1] https://software.intel.com/sites/default/files/managed/c5/15/vt-directed-io-spec.pdf
[2] https://docs.microsoft.com/en-us/windows/security/information-protection/kernel-dma-protection-for-thunderbolt

Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Joerg Roedel <jroedel@suse.de>
2018-12-05 12:01:55 +03:00

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/*
* Copyright (c) 2006, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place - Suite 330, Boston, MA 02111-1307 USA.
*
* Copyright (C) Ashok Raj <ashok.raj@intel.com>
* Copyright (C) Shaohua Li <shaohua.li@intel.com>
*/
#ifndef __DMAR_H__
#define __DMAR_H__
#include <linux/acpi.h>
#include <linux/types.h>
#include <linux/msi.h>
#include <linux/irqreturn.h>
#include <linux/rwsem.h>
#include <linux/rculist.h>
struct acpi_dmar_header;
#ifdef CONFIG_X86
# define DMAR_UNITS_SUPPORTED MAX_IO_APICS
#else
# define DMAR_UNITS_SUPPORTED 64
#endif
/* DMAR Flags */
#define DMAR_INTR_REMAP 0x1
#define DMAR_X2APIC_OPT_OUT 0x2
#define DMAR_PLATFORM_OPT_IN 0x4
struct intel_iommu;
struct dmar_dev_scope {
struct device __rcu *dev;
u8 bus;
u8 devfn;
};
#ifdef CONFIG_DMAR_TABLE
extern struct acpi_table_header *dmar_tbl;
struct dmar_drhd_unit {
struct list_head list; /* list of drhd units */
struct acpi_dmar_header *hdr; /* ACPI header */
u64 reg_base_addr; /* register base address*/
struct dmar_dev_scope *devices;/* target device array */
int devices_cnt; /* target device count */
u16 segment; /* PCI domain */
u8 ignored:1; /* ignore drhd */
u8 include_all:1;
struct intel_iommu *iommu;
};
struct dmar_pci_path {
u8 bus;
u8 device;
u8 function;
};
struct dmar_pci_notify_info {
struct pci_dev *dev;
unsigned long event;
int bus;
u16 seg;
u16 level;
struct dmar_pci_path path[];
} __attribute__((packed));
extern struct rw_semaphore dmar_global_lock;
extern struct list_head dmar_drhd_units;
#define for_each_drhd_unit(drhd) \
list_for_each_entry_rcu(drhd, &dmar_drhd_units, list)
#define for_each_active_drhd_unit(drhd) \
list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \
if (drhd->ignored) {} else
#define for_each_active_iommu(i, drhd) \
list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \
if (i=drhd->iommu, drhd->ignored) {} else
#define for_each_iommu(i, drhd) \
list_for_each_entry_rcu(drhd, &dmar_drhd_units, list) \
if (i=drhd->iommu, 0) {} else
static inline bool dmar_rcu_check(void)
{
return rwsem_is_locked(&dmar_global_lock) ||
system_state == SYSTEM_BOOTING;
}
#define dmar_rcu_dereference(p) rcu_dereference_check((p), dmar_rcu_check())
#define for_each_dev_scope(a, c, p, d) \
for ((p) = 0; ((d) = (p) < (c) ? dmar_rcu_dereference((a)[(p)].dev) : \
NULL, (p) < (c)); (p)++)
#define for_each_active_dev_scope(a, c, p, d) \
for_each_dev_scope((a), (c), (p), (d)) if (!(d)) { continue; } else
extern int dmar_table_init(void);
extern int dmar_dev_scope_init(void);
extern void dmar_register_bus_notifier(void);
extern int dmar_parse_dev_scope(void *start, void *end, int *cnt,
struct dmar_dev_scope **devices, u16 segment);
extern void *dmar_alloc_dev_scope(void *start, void *end, int *cnt);
extern void dmar_free_dev_scope(struct dmar_dev_scope **devices, int *cnt);
extern int dmar_insert_dev_scope(struct dmar_pci_notify_info *info,
void *start, void*end, u16 segment,
struct dmar_dev_scope *devices,
int devices_cnt);
extern int dmar_remove_dev_scope(struct dmar_pci_notify_info *info,
u16 segment, struct dmar_dev_scope *devices,
int count);
/* Intel IOMMU detection */
extern int detect_intel_iommu(void);
extern int enable_drhd_fault_handling(void);
extern int dmar_device_add(acpi_handle handle);
extern int dmar_device_remove(acpi_handle handle);
static inline int dmar_res_noop(struct acpi_dmar_header *hdr, void *arg)
{
return 0;
}
#ifdef CONFIG_INTEL_IOMMU
extern int iommu_detected, no_iommu;
extern int intel_iommu_init(void);
extern int dmar_parse_one_rmrr(struct acpi_dmar_header *header, void *arg);
extern int dmar_parse_one_atsr(struct acpi_dmar_header *header, void *arg);
extern int dmar_check_one_atsr(struct acpi_dmar_header *hdr, void *arg);
extern int dmar_release_one_atsr(struct acpi_dmar_header *hdr, void *arg);
extern int dmar_iommu_hotplug(struct dmar_drhd_unit *dmaru, bool insert);
extern int dmar_iommu_notify_scope_dev(struct dmar_pci_notify_info *info);
#else /* !CONFIG_INTEL_IOMMU: */
static inline int intel_iommu_init(void) { return -ENODEV; }
#define dmar_parse_one_rmrr dmar_res_noop
#define dmar_parse_one_atsr dmar_res_noop
#define dmar_check_one_atsr dmar_res_noop
#define dmar_release_one_atsr dmar_res_noop
static inline int dmar_iommu_notify_scope_dev(struct dmar_pci_notify_info *info)
{
return 0;
}
static inline int dmar_iommu_hotplug(struct dmar_drhd_unit *dmaru, bool insert)
{
return 0;
}
#endif /* CONFIG_INTEL_IOMMU */
#ifdef CONFIG_IRQ_REMAP
extern int dmar_ir_hotplug(struct dmar_drhd_unit *dmaru, bool insert);
#else /* CONFIG_IRQ_REMAP */
static inline int dmar_ir_hotplug(struct dmar_drhd_unit *dmaru, bool insert)
{ return 0; }
#endif /* CONFIG_IRQ_REMAP */
extern bool dmar_platform_optin(void);
#else /* CONFIG_DMAR_TABLE */
static inline int dmar_device_add(void *handle)
{
return 0;
}
static inline int dmar_device_remove(void *handle)
{
return 0;
}
static inline bool dmar_platform_optin(void)
{
return false;
}
#endif /* CONFIG_DMAR_TABLE */
struct irte {
union {
/* Shared between remapped and posted mode*/
struct {
__u64 present : 1, /* 0 */
fpd : 1, /* 1 */
__res0 : 6, /* 2 - 6 */
avail : 4, /* 8 - 11 */
__res1 : 3, /* 12 - 14 */
pst : 1, /* 15 */
vector : 8, /* 16 - 23 */
__res2 : 40; /* 24 - 63 */
};
/* Remapped mode */
struct {
__u64 r_present : 1, /* 0 */
r_fpd : 1, /* 1 */
dst_mode : 1, /* 2 */
redir_hint : 1, /* 3 */
trigger_mode : 1, /* 4 */
dlvry_mode : 3, /* 5 - 7 */
r_avail : 4, /* 8 - 11 */
r_res0 : 4, /* 12 - 15 */
r_vector : 8, /* 16 - 23 */
r_res1 : 8, /* 24 - 31 */
dest_id : 32; /* 32 - 63 */
};
/* Posted mode */
struct {
__u64 p_present : 1, /* 0 */
p_fpd : 1, /* 1 */
p_res0 : 6, /* 2 - 7 */
p_avail : 4, /* 8 - 11 */
p_res1 : 2, /* 12 - 13 */
p_urgent : 1, /* 14 */
p_pst : 1, /* 15 */
p_vector : 8, /* 16 - 23 */
p_res2 : 14, /* 24 - 37 */
pda_l : 26; /* 38 - 63 */
};
__u64 low;
};
union {
/* Shared between remapped and posted mode*/
struct {
__u64 sid : 16, /* 64 - 79 */
sq : 2, /* 80 - 81 */
svt : 2, /* 82 - 83 */
__res3 : 44; /* 84 - 127 */
};
/* Posted mode*/
struct {
__u64 p_sid : 16, /* 64 - 79 */
p_sq : 2, /* 80 - 81 */
p_svt : 2, /* 82 - 83 */
p_res3 : 12, /* 84 - 95 */
pda_h : 32; /* 96 - 127 */
};
__u64 high;
};
};
static inline void dmar_copy_shared_irte(struct irte *dst, struct irte *src)
{
dst->present = src->present;
dst->fpd = src->fpd;
dst->avail = src->avail;
dst->pst = src->pst;
dst->vector = src->vector;
dst->sid = src->sid;
dst->sq = src->sq;
dst->svt = src->svt;
}
#define PDA_LOW_BIT 26
#define PDA_HIGH_BIT 32
/* Can't use the common MSI interrupt functions
* since DMAR is not a pci device
*/
struct irq_data;
extern void dmar_msi_unmask(struct irq_data *data);
extern void dmar_msi_mask(struct irq_data *data);
extern void dmar_msi_read(int irq, struct msi_msg *msg);
extern void dmar_msi_write(int irq, struct msi_msg *msg);
extern int dmar_set_interrupt(struct intel_iommu *iommu);
extern irqreturn_t dmar_fault(int irq, void *dev_id);
extern int dmar_alloc_hwirq(int id, int node, void *arg);
extern void dmar_free_hwirq(int irq);
#endif /* __DMAR_H__ */
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