intel-iommu: add DMAR table to ACPI tables

Expose Intel IOMMU to the BIOS. If object of TYPE_INTEL_IOMMU_DEVICE exists,
add DMAR table to ACPI RSDT table. For now the DMAR table indicates that there
is only one hardware unit without INTR_REMAP capability on the platform.
Signed-off-by: NLe Tan <tamlokveer@gmail.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/i386/acpi-build.c

@@ -49,6 +49,7 @@
 #include "hw/i386/ich9.h"
 #include "hw/pci/pci_bus.h"
 #include "hw/pci-host/q35.h"
+#include "hw/i386/intel_iommu.h"
 
 #include "hw/i386/q35-acpi-dsdt.hex"
 #include "hw/i386/acpi-dsdt.hex"
@@ -1387,6 +1388,30 @@ build_mcfg_q35(GArray *table_data, GArray *linker, AcpiMcfgInfo *info)
     build_header(linker, table_data, (void *)mcfg, sig, len, 1);
 }
 
+static void
+build_dmar_q35(GArray *table_data, GArray *linker)
+{
+    int dmar_start = table_data->len;
+
+    AcpiTableDmar *dmar;
+    AcpiDmarHardwareUnit *drhd;
+
+    dmar = acpi_data_push(table_data, sizeof(*dmar));
+    dmar->host_address_width = VTD_HOST_ADDRESS_WIDTH - 1;
+    dmar->flags = 0;    /* No intr_remap for now */
+
+    /* 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->flags = ACPI_DMAR_INCLUDE_PCI_ALL;
+    drhd->pci_segment = cpu_to_le16(0);
+    drhd->address = cpu_to_le64(Q35_HOST_BRIDGE_IOMMU_ADDR);
+
+    build_header(linker, table_data, (void *)(table_data->data + dmar_start),
+                 "DMAR", table_data->len - dmar_start, 1);
+}
+
 static void
 build_dsdt(GArray *table_data, GArray *linker, AcpiMiscInfo *misc)
 {
@@ -1508,6 +1533,16 @@ static bool acpi_get_mcfg(AcpiMcfgInfo *mcfg)
     return true;
 }
 
+static bool acpi_has_iommu(void)
+{
+    bool ambiguous;
+    Object *intel_iommu;
+
+    intel_iommu = object_resolve_path_type("", TYPE_INTEL_IOMMU_DEVICE,
+                                           &ambiguous);
+    return intel_iommu && !ambiguous;
+}
+
 static
 void acpi_build(PcGuestInfo *guest_info, AcpiBuildTables *tables)
 {
@@ -1584,6 +1619,10 @@ void acpi_build(PcGuestInfo *guest_info, AcpiBuildTables *tables)
         acpi_add_table(table_offsets, tables->table_data);
         build_mcfg_q35(tables->table_data, tables->linker, &mcfg);
     }
+    if (acpi_has_iommu()) {
+        acpi_add_table(table_offsets, tables->table_data);
+        build_dmar_q35(tables->table_data, tables->linker);
+    }
 
     /* Add tables supplied by user (if any) */
     for (u = acpi_table_first(); u; u = acpi_table_next(u)) {

hw/i386/acpi-defs.h

@@ -325,4 +325,44 @@ struct Acpi20Tcpa {
 } QEMU_PACKED;
 typedef struct Acpi20Tcpa Acpi20Tcpa;
 
+/* DMAR - DMA Remapping table r2.2 */
+struct AcpiTableDmar {
+    ACPI_TABLE_HEADER_DEF
+    uint8_t host_address_width; /* Maximum DMA physical addressability */
+    uint8_t flags;
+    uint8_t reserved[10];
+} QEMU_PACKED;
+typedef struct AcpiTableDmar AcpiTableDmar;
+
+/* Masks for Flags field above */
+#define ACPI_DMAR_INTR_REMAP        1
+#define ACPI_DMAR_X2APIC_OPT_OUT    (1 << 1)
+
+/* Values for sub-structure type for DMAR */
+enum {
+    ACPI_DMAR_TYPE_HARDWARE_UNIT = 0,       /* DRHD */
+    ACPI_DMAR_TYPE_RESERVED_MEMORY = 1,     /* RMRR */
+    ACPI_DMAR_TYPE_ATSR = 2,                /* ATSR */
+    ACPI_DMAR_TYPE_HARDWARE_AFFINITY = 3,   /* RHSR */
+    ACPI_DMAR_TYPE_ANDD = 4,                /* ANDD */
+    ACPI_DMAR_TYPE_RESERVED = 5             /* Reserved for furture use */
+};
+
+/*
+ * Sub-structures for DMAR
+ */
+/* Type 0: Hardware Unit Definition */
+struct AcpiDmarHardwareUnit {
+    uint16_t type;
+    uint16_t length;
+    uint8_t flags;
+    uint8_t reserved;
+    uint16_t pci_segment;   /* The PCI Segment associated with this unit */
+    uint64_t address;   /* Base address of remapping hardware register-set */
+} QEMU_PACKED;
+typedef struct AcpiDmarHardwareUnit AcpiDmarHardwareUnit;
+
+/* Masks for Flags field above */
+#define ACPI_DMAR_INCLUDE_PCI_ALL   1
+
 #endif