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 <weidong.han@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
index 44025a0c..4f5b871 100644
--- a/drivers/pci/intr_remapping.c
+++ b/drivers/pci/intr_remapping.c
@@ -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 @@
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 @@
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 @@
" 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;
}