From f007e99c8e2e322b8331aba72414715119a2920d Mon Sep 17 00:00:00 2001 From: Weidong Han Date: Sat, 23 May 2009 00:41:15 +0800 Subject: [PATCH] Intel-IOMMU, intr-remap: source-id checking 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 Signed-off-by: David Woodhouse --- arch/x86/kernel/apic/io_apic.c | 6 ++ drivers/pci/intr_remapping.c | 120 ++++++++++++++++++++++++++++++++- drivers/pci/intr_remapping.h | 2 + include/linux/dmar.h | 11 +++ 4 files changed, 136 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index b7a79207295e..4d0216fcb36c 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -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; diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c index 44025a0c2bb6..4f5b8712931f 100644 --- a/drivers/pci/intr_remapping.c +++ b/drivers/pci/intr_remapping.c @@ -10,6 +10,8 @@ #include #include "intr_remapping.h" #include +#include +#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; } diff --git a/drivers/pci/intr_remapping.h b/drivers/pci/intr_remapping.h index ca48f0df8ac9..63a263c18415 100644 --- a/drivers/pci/intr_remapping.h +++ b/drivers/pci/intr_remapping.h @@ -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) diff --git a/include/linux/dmar.h b/include/linux/dmar.h index 1731fb5fd775..4a2b162c256a 100644 --- a/include/linux/dmar.h +++ b/include/linux/dmar.h @@ -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)