acpi: build_dmar_q35: use acpi_table_begin()/acpi_table_end() instead of build_header()

it replaces error-prone pointer arithmetic for build_header() API,
with 2 calls to start and finish table creation,
which hides offsets magic from API user.

While at it switch to build_append_int_noprefix() to build
table entries tables.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Message-Id: <20210924122802.1455362-19-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 48 insertions, 39 deletions

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 078097a..c65ab1d 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -2086,8 +2086,9 @@ build_srat(GArray *table_data, BIOSLinker *linker, MachineState *machine)
 static void
 insert_scope(PCIBus *bus, PCIDevice *dev, void *opaque)
 {
+    const size_t device_scope_size = 6 /* device scope structure */ +
+                                     2 /* 1 path entry */;
     GArray *scope_blob = opaque;
-    AcpiDmarDeviceScope *scope = NULL;
 
     if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_BRIDGE)) {
         /* Dmar Scope Type: 0x02 for PCI Bridge */
@@ -2098,8 +2099,7 @@ insert_scope(PCIBus *bus, PCIDevice *dev, void *opaque)
     }
 
     /* length */
-    build_append_int_noprefix(scope_blob,
-                              sizeof(*scope) + sizeof(scope->path[0]), 1);
+    build_append_int_noprefix(scope_blob, device_scope_size, 1);
     /* reserved */
     build_append_int_noprefix(scope_blob, 0, 2);
     /* enumeration_id */
@@ -2131,26 +2131,26 @@ dmar_host_bridges(Object *obj, void *opaque)
 }
 
 /*
- * VT-d spec 8.1 DMA Remapping Reporting Structure
- * (version Oct. 2014 or later)
+ * Intel ® Virtualization Technology for Directed I/O
+ * Architecture Specification. Revision 3.3
+ * 8.1 DMA Remapping Reporting Structure
  */
 static void
 build_dmar_q35(GArray *table_data, BIOSLinker *linker, const char *oem_id,
                const char *oem_table_id)
 {
-    int dmar_start = table_data->len;
-
-    AcpiTableDmar *dmar;
-    AcpiDmarHardwareUnit *drhd;
-    AcpiDmarRootPortATS *atsr;
     uint8_t dmar_flags = 0;
+    uint8_t rsvd10[10] = {};
+    /* Root complex IOAPIC uses one path only */
+    const size_t ioapic_scope_size = 6 /* device scope structure */ +
+                                     2 /* 1 path entry */;
     X86IOMMUState *iommu = x86_iommu_get_default();
-    AcpiDmarDeviceScope *scope = NULL;
-    /* Root complex IOAPIC use one path[0] only */
-    size_t ioapic_scope_size = sizeof(*scope) + sizeof(scope->path[0]);
     IntelIOMMUState *intel_iommu = INTEL_IOMMU_DEVICE(iommu);
     GArray *scope_blob = g_array_new(false, true, 1);
 
+    AcpiTable table = { .sig = "DMAR", .rev = 1, .oem_id = oem_id,
+                        .oem_table_id = oem_table_id };
+
     /*
      * A PCI bus walk, for each PCI host bridge.
      * Insert scope for each PCI bridge and endpoint device which
@@ -2164,43 +2164,52 @@ build_dmar_q35(GArray *table_data, BIOSLinker *linker, const char *oem_id,
         dmar_flags |= 0x1;      /* Flags: 0x1: INT_REMAP */
     }
 
-    dmar = acpi_data_push(table_data, sizeof(*dmar));
-    dmar->host_address_width = intel_iommu->aw_bits - 1;
-    dmar->flags = dmar_flags;
-
-    /* DMAR Remapping Hardware Unit Definition structure */
-    drhd = acpi_data_push(table_data, sizeof(*drhd) + ioapic_scope_size);
-    drhd->type = cpu_to_le16(ACPI_DMAR_TYPE_HARDWARE_UNIT);
-    drhd->length =
-        cpu_to_le16(sizeof(*drhd) + ioapic_scope_size + scope_blob->len);
-    drhd->flags = 0;            /* Don't include all pci device */
-    drhd->pci_segment = cpu_to_le16(0);
-    drhd->address = cpu_to_le64(Q35_HOST_BRIDGE_IOMMU_ADDR);
+    acpi_table_begin(&table, table_data);
+    /* Host Address Width */
+    build_append_int_noprefix(table_data, intel_iommu->aw_bits - 1, 1);
+    build_append_int_noprefix(table_data, dmar_flags, 1); /* Flags */
+    g_array_append_vals(table_data, rsvd10, sizeof(rsvd10)); /* Reserved */
+
+    /* 8.3 DMAR Remapping Hardware Unit Definition structure */
+    build_append_int_noprefix(table_data, 0, 2); /* Type */
+    /* Length */
+    build_append_int_noprefix(table_data,
+                              16 + ioapic_scope_size + scope_blob->len, 2);
+    /* Flags */
+    build_append_int_noprefix(table_data, 0 /* Don't include all pci device */ ,
+                              1);
+    build_append_int_noprefix(table_data, 0 , 1); /* Reserved */
+    build_append_int_noprefix(table_data, 0 , 2); /* Segment Number */
+    /* Register Base Address */
+    build_append_int_noprefix(table_data, Q35_HOST_BRIDGE_IOMMU_ADDR , 8);
 
     /* Scope definition for the root-complex IOAPIC. See VT-d spec
      * 8.3.1 (version Oct. 2014 or later). */
-    scope = &drhd->scope[0];
-    scope->entry_type = 0x03;   /* Type: 0x03 for IOAPIC */
-    scope->length = ioapic_scope_size;
-    scope->enumeration_id = ACPI_BUILD_IOAPIC_ID;
-    scope->bus = Q35_PSEUDO_BUS_PLATFORM;
-    scope->path[0].device = PCI_SLOT(Q35_PSEUDO_DEVFN_IOAPIC);
-    scope->path[0].function = PCI_FUNC(Q35_PSEUDO_DEVFN_IOAPIC);
+    build_append_int_noprefix(table_data, 0x03 /* IOAPIC */, 1); /* Type */
+    build_append_int_noprefix(table_data, ioapic_scope_size, 1); /* Length */
+    build_append_int_noprefix(table_data, 0, 2); /* Reserved */
+    /* Enumeration ID */
+    build_append_int_noprefix(table_data, ACPI_BUILD_IOAPIC_ID, 1);
+    /* Start Bus Number */
+    build_append_int_noprefix(table_data, Q35_PSEUDO_BUS_PLATFORM, 1);
+    /* Path, {Device, Function} pair */
+    build_append_int_noprefix(table_data, PCI_SLOT(Q35_PSEUDO_DEVFN_IOAPIC), 1);
+    build_append_int_noprefix(table_data, PCI_FUNC(Q35_PSEUDO_DEVFN_IOAPIC), 1);
 
     /* Add scope found above */
     g_array_append_vals(table_data, scope_blob->data, scope_blob->len);
     g_array_free(scope_blob, true);
 
     if (iommu->dt_supported) {
-        atsr = acpi_data_push(table_data, sizeof(*atsr));
-        atsr->type = cpu_to_le16(ACPI_DMAR_TYPE_ATSR);
-        atsr->length = cpu_to_le16(sizeof(*atsr));
-        atsr->flags = ACPI_DMAR_ATSR_ALL_PORTS;
-        atsr->pci_segment = cpu_to_le16(0);
+        /* 8.5 Root Port ATS Capability Reporting Structure */
+        build_append_int_noprefix(table_data, 2, 2); /* Type */
+        build_append_int_noprefix(table_data, 8, 2); /* Length */
+        build_append_int_noprefix(table_data, 1 /* ALL_PORTS */, 1); /* Flags */
+        build_append_int_noprefix(table_data, 0, 1); /* Reserved */
+        build_append_int_noprefix(table_data, 0, 2); /* Segment Number */
     }
 
-    build_header(linker, table_data, (void *)(table_data->data + dmar_start),
-                 "DMAR", table_data->len - dmar_start, 1, oem_id, oem_table_id);
+    acpi_table_end(linker, &table);
 }
 
 /*