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Intel-IOMMU, intr-remap: source-id checking

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To support domain-isolation usages, the platform hardware must be
capable of uniquely identifying the requestor (source-id) for each
interrupt message. Without source-id checking for interrupt remapping
, a rouge guest/VM with assigned devices can launch interrupt attacks
to bring down anothe guest/VM or the VMM itself.

This patch adds source-id checking for interrupt remapping, and then
really isolates interrupts for guests/VMs with assigned devices.

Because PCI subsystem is not initialized yet when set up IOAPIC
entries, use read_pci_config_byte to access PCI config space directly.

Signed-off-by: Weidong Han <weidong.han@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Weidong Han 2009-05-23 00:41:15 +08:00 committed by David Woodhouse
parent c4658b4e77
commit f007e99c8e
4 changed files with 136 additions and 3 deletions
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6
arch/x86/kernel/apic/io_apic.c
View file

@ -1414,6 +1414,9 @@ int setup_ioapic_entry(int apic_id, int irq,
irte.vector = vector;
irte.dest_id = IRTE_DEST(destination);
/* Set source-id of interrupt request */
set_ioapic_sid(&irte, apic_id);
modify_irte(irq, &irte);
ir_entry->index2 = (index >> 15) & 0x1;
@ -3290,6 +3293,9 @@ static int msi_compose_msg(struct pci_dev *pdev, unsigned int irq, struct msi_ms
irte.vector = cfg->vector;
irte.dest_id = IRTE_DEST(dest);
/* Set source-id of interrupt request */
set_msi_sid(&irte, pdev);
modify_irte(irq, &irte);
msg->address_hi = MSI_ADDR_BASE_HI;

120
drivers/pci/intr_remapping.c
View file

@ -10,6 +10,8 @@
#include <linux/intel-iommu.h>
#include "intr_remapping.h"
#include <acpi/acpi.h>
#include <asm/pci-direct.h>
#include "pci.h"
static struct ioapic_scope ir_ioapic[MAX_IO_APICS];
static int ir_ioapic_num;
@ -418,6 +420,91 @@ int free_irte(int irq)
return rc;
}
/*
* source validation type
*/
#define SVT_NO_VERIFY 0x0 /* no verification is required */
#define SVT_VERIFY_SID_SQ 0x1 /* verify using SID and SQ fiels */
#define SVT_VERIFY_BUS 0x2 /* verify bus of request-id */
/*
* source-id qualifier
*/
#define SQ_ALL_16 0x0 /* verify all 16 bits of request-id */
#define SQ_13_IGNORE_1 0x1 /* verify most significant 13 bits, ignore
* the third least significant bit
*/
#define SQ_13_IGNORE_2 0x2 /* verify most significant 13 bits, ignore
* the second and third least significant bits
*/
#define SQ_13_IGNORE_3 0x3 /* verify most significant 13 bits, ignore
* the least three significant bits
*/
/*
* set SVT, SQ and SID fields of irte to verify
* source ids of interrupt requests
*/
static void set_irte_sid(struct irte *irte, unsigned int svt,
unsigned int sq, unsigned int sid)
{
irte->svt = svt;
irte->sq = sq;
irte->sid = sid;
}
int set_ioapic_sid(struct irte *irte, int apic)
{
int i;
u16 sid = 0;
if (!irte)
return -1;
for (i = 0; i < MAX_IO_APICS; i++) {
if (ir_ioapic[i].id == apic) {
sid = (ir_ioapic[i].bus << 8) | ir_ioapic[i].devfn;
break;
}
}
if (sid == 0) {
pr_warning("Failed to set source-id of IOAPIC (%d)\n", apic);
return -1;
}
set_irte_sid(irte, 1, 0, sid);
return 0;
}
int set_msi_sid(struct irte *irte, struct pci_dev *dev)
{
struct pci_dev *bridge;
if (!irte || !dev)
return -1;
/* PCIe device or Root Complex integrated PCI device */
if (dev->is_pcie || !dev->bus->parent) {
set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_ALL_16,
(dev->bus->number << 8) | dev->devfn);
return 0;
}
bridge = pci_find_upstream_pcie_bridge(dev);
if (bridge) {
if (bridge->is_pcie) /* this is a PCIE-to-PCI/PCIX bridge */
set_irte_sid(irte, SVT_VERIFY_BUS, SQ_ALL_16,
(bridge->bus->number << 8) | dev->bus->number);
else /* this is a legacy PCI bridge */
set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_ALL_16,
(bridge->bus->number << 8) | bridge->devfn);
}
return 0;
}
static void iommu_set_intr_remapping(struct intel_iommu *iommu, int mode)
{
u64 addr;
@ -624,6 +711,35 @@ int __init enable_intr_remapping(int eim)
return -1;
}
static void ir_parse_one_ioapic_scope(struct acpi_dmar_device_scope *scope,
struct intel_iommu *iommu)
{
struct acpi_dmar_pci_path *path;
u8 bus;
int count;
bus = scope->bus;
path = (struct acpi_dmar_pci_path *)(scope + 1);
count = (scope->length - sizeof(struct acpi_dmar_device_scope))
/ sizeof(struct acpi_dmar_pci_path);
while (--count > 0) {
/*
* Access PCI directly due to the PCI
* subsystem isn't initialized yet.
*/
bus = read_pci_config_byte(bus, path->dev, path->fn,
PCI_SECONDARY_BUS);
path++;
}
ir_ioapic[ir_ioapic_num].bus = bus;
ir_ioapic[ir_ioapic_num].devfn = PCI_DEVFN(path->dev, path->fn);
ir_ioapic[ir_ioapic_num].iommu = iommu;
ir_ioapic[ir_ioapic_num].id = scope->enumeration_id;
ir_ioapic_num++;
}
static int ir_parse_ioapic_scope(struct acpi_dmar_header *header,
struct intel_iommu *iommu)
{
@ -648,9 +764,7 @@ static int ir_parse_ioapic_scope(struct acpi_dmar_header *header,
" 0x%Lx\n", scope->enumeration_id,
drhd->address);
ir_ioapic[ir_ioapic_num].iommu = iommu;
ir_ioapic[ir_ioapic_num].id = scope->enumeration_id;
ir_ioapic_num++;
ir_parse_one_ioapic_scope(scope, iommu);
}
start += scope->length;
}

2
drivers/pci/intr_remapping.h
View file

@ -3,6 +3,8 @@
struct ioapic_scope {
struct intel_iommu *iommu;
unsigned int id;
unsigned int bus; /* PCI bus number */
unsigned int devfn; /* PCI devfn number */
};
#define IR_X2APIC_MODE(mode) (mode ? (1 << 11) : 0)

11
include/linux/dmar.h
View file

@ -126,6 +126,8 @@ extern int free_irte(int irq);
extern int irq_remapped(int irq);
extern struct intel_iommu *map_dev_to_ir(struct pci_dev *dev);
extern struct intel_iommu *map_ioapic_to_ir(int apic);
extern int set_ioapic_sid(struct irte *irte, int apic);
extern int set_msi_sid(struct irte *irte, struct pci_dev *dev);
#else
static inline int alloc_irte(struct intel_iommu *iommu, int irq, u16 count)
{
@ -156,6 +158,15 @@ static inline struct intel_iommu *map_ioapic_to_ir(int apic)
{
return NULL;
}
static inline int set_ioapic_sid(struct irte *irte, int apic)
{
return 0;
}
static inline int set_msi_sid(struct irte *irte, struct pci_dev *dev)
{
return 0;
}
#define irq_remapped(irq) (0)
#define enable_intr_remapping(mode) (-1)
#define disable_intr_remapping() (0)