[Qemu-devel] [PATCH v8 04/25] acpi: add DMAR scope definition for root IOAPIC

[Peter Xu <peterx@redhat.com>]

To enable interrupt remapping for intel IOMMU device, each IOAPIC device
in the system reported via ACPI MADT must be explicitly enumerated under
one specific remapping hardware unit. This patch adds the root-complex
IOAPIC into the default DMAR device.

Please refer to VT-d spec 8.3.1.1 for more information.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/i386/acpi-build.c        | 17 +++++++++++++++--
 include/hw/acpi/acpi-defs.h | 15 +++++++++++++++
 include/hw/pci-host/q35.h   |  9 +++++++++
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index ddc6f16..6c572a3 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -77,6 +77,9 @@
 #define ACPI_BUILD_DPRINTF(fmt, ...)
 #endif
 
+/* Default IOAPIC ID */
+#define ACPI_BUILD_IOAPIC_ID 0x0
+
 typedef struct AcpiMcfgInfo {
     uint64_t mcfg_base;
     uint32_t mcfg_size;
@@ -375,7 +378,6 @@ build_madt(GArray *table_data, GArray *linker, PCMachineState *pcms)
     io_apic = acpi_data_push(table_data, sizeof *io_apic);
     io_apic->type = ACPI_APIC_IO;
     io_apic->length = sizeof(*io_apic);
-#define ACPI_BUILD_IOAPIC_ID 0x0
     io_apic->io_apic_id = ACPI_BUILD_IOAPIC_ID;
     io_apic->address = cpu_to_le32(IO_APIC_DEFAULT_ADDRESS);
     io_apic->interrupt = cpu_to_le32(0);
@@ -2561,6 +2563,9 @@ build_dmar_q35(MachineState *ms, GArray *table_data, GArray *linker)
     AcpiTableDmar *dmar;
     AcpiDmarHardwareUnit *drhd;
     uint8_t dmar_flags = 0;
+    AcpiDmarDeviceScope *scope = NULL;
+    /* Root complex IOAPIC use one path[0] only */
+    uint16_t scope_size = sizeof(*scope) + sizeof(uint16_t);
 
     if (ms->iommu_intr) {
         /* enable INTR for the IOMMU device */
@@ -2574,11 +2579,19 @@ build_dmar_q35(MachineState *ms, GArray *table_data, GArray *linker)
     /* DMAR Remapping Hardware Unit Definition structure */
     drhd = acpi_data_push(table_data, sizeof(*drhd));
     drhd->type = cpu_to_le16(ACPI_DMAR_TYPE_HARDWARE_UNIT);
-    drhd->length = cpu_to_le16(sizeof(*drhd));   /* No device scope now */
+    drhd->length = cpu_to_le16(sizeof(*drhd) + scope_size);
     drhd->flags = ACPI_DMAR_INCLUDE_PCI_ALL;
     drhd->pci_segment = cpu_to_le16(0);
     drhd->address = cpu_to_le64(Q35_HOST_BRIDGE_IOMMU_ADDR);
 
+    /* Scope definition for the root-complex IOAPIC */
+    scope = acpi_data_push(table_data, scope_size);
+    scope->entry_type = cpu_to_le16(ACPI_DMAR_DEV_SCOPE_TYPE_IOAPIC);
+    scope->length = scope_size;
+    scope->enumeration_id = cpu_to_le16(ACPI_BUILD_IOAPIC_ID);
+    scope->bus = cpu_to_le16(Q35_PSEUDO_BUS_PLATFORM);
+    scope->path[0] = cpu_to_le16(Q35_PSEUDO_DEVFN_IOAPIC);
+
     build_header(linker, table_data, (void *)(table_data->data + dmar_start),
                  "DMAR", table_data->len - dmar_start, 1, NULL, NULL);
 }
diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
index 850a962..b46e472 100644
--- a/include/hw/acpi/acpi-defs.h
+++ b/include/hw/acpi/acpi-defs.h
@@ -569,6 +569,20 @@ enum {
 /*
  * Sub-structures for DMAR
  */
+
+#define ACPI_DMAR_DEV_SCOPE_TYPE_IOAPIC     (0x03)
+
+/* Device scope structure for DRHD. */
+struct AcpiDmarDeviceScope {
+    uint8_t entry_type;
+    uint8_t length;
+    uint16_t reserved;
+    uint8_t enumeration_id;
+    uint8_t bus;
+    uint16_t path[0];           /* list of dev:func pairs */
+} QEMU_PACKED;
+typedef struct AcpiDmarDeviceScope AcpiDmarDeviceScope;
+
 /* Type 0: Hardware Unit Definition */
 struct AcpiDmarHardwareUnit {
     uint16_t type;
@@ -577,6 +591,7 @@ struct AcpiDmarHardwareUnit {
     uint8_t reserved;
     uint16_t pci_segment;   /* The PCI Segment associated with this unit */
     uint64_t address;   /* Base address of remapping hardware register-set */
+    AcpiDmarDeviceScope scope[0];
 } QEMU_PACKED;
 typedef struct AcpiDmarHardwareUnit AcpiDmarHardwareUnit;
 
diff --git a/include/hw/pci-host/q35.h b/include/hw/pci-host/q35.h
index c5c073d..9afc221 100644
--- a/include/hw/pci-host/q35.h
+++ b/include/hw/pci-host/q35.h
@@ -175,4 +175,13 @@ typedef struct Q35PCIHost {
 
 uint64_t mch_mcfg_base(void);
 
+/*
+ * Arbitary but unique BNF number for IOAPIC device. This is only
+ * used when interrupt remapping is enabled.
+ *
+ * TODO: make sure there would have no conflict with real PCI bus
+ */
+#define Q35_PSEUDO_BUS_PLATFORM         (0xff)
+#define Q35_PSEUDO_DEVFN_IOAPIC         (0x00)
+
 #endif /* HW_Q35_H */
-- 
2.4.11