hw: arm: Support both legacy and current RSDP build

We add the ability to build legacy or current RSDP tables, based on the
AcpiRsdpData revision field passed to build_rsdp().
Although arm/virt only uses RSDP v2, adding that capability to
build_rsdp will allow us to share the RSDP build code between ARM and x86.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/arm/virt-acpi-build.c

@@ -372,6 +372,20 @@ build_rsdp(GArray *tbl, BIOSLinker *linker, AcpiRsdpData *rsdp_data)
 {
     int tbl_off = tbl->len; /* Table offset in the RSDP file */
 
+    switch (rsdp_data->revision) {
+    case 0:
+        /* With ACPI 1.0, we must have an RSDT pointer */
+        g_assert(rsdp_data->rsdt_tbl_offset);
+        break;
+    case 2:
+        /* With ACPI 2.0+, we must have an XSDT pointer */
+        g_assert(rsdp_data->xsdt_tbl_offset);
+        break;
+    default:
+        /* Only revisions 0 (ACPI 1.0) and 2 (ACPI 2.0+) are valid for RSDP */
+        g_assert_not_reached();
+    }
+
     bios_linker_loader_alloc(linker, ACPI_BUILD_RSDP_FILE, tbl, 16,
                              true /* fseg memory */);
 
@@ -380,10 +394,29 @@ build_rsdp(GArray *tbl, BIOSLinker *linker, AcpiRsdpData *rsdp_data)
     g_array_append_vals(tbl, rsdp_data->oem_id, 6); /* OEMID */
     build_append_int_noprefix(tbl, rsdp_data->revision, 1); /* Revision */
     build_append_int_noprefix(tbl, 0, 4); /* RsdtAddress */
+    if (rsdp_data->rsdt_tbl_offset) {
+        /* RSDT address to be filled by guest linker */
+        bios_linker_loader_add_pointer(linker, ACPI_BUILD_RSDP_FILE,
+                                       tbl_off + 16, 4,
+                                       ACPI_BUILD_TABLE_FILE,
+                                       *rsdp_data->rsdt_tbl_offset);
+    }
+
+    /* Checksum to be filled by guest linker */
+    bios_linker_loader_add_checksum(linker, ACPI_BUILD_RSDP_FILE,
+                                    tbl_off, 20, /* ACPI rev 1.0 RSDP size */
+                                    8);
+
+    if (rsdp_data->revision == 0) {
+        /* ACPI 1.0 RSDP, we're done */
+        return;
+    }
+
     build_append_int_noprefix(tbl, 36, 4); /* Length */
 
     /* XSDT address to be filled by guest linker */
     build_append_int_noprefix(tbl, 0, 8); /* XsdtAddress */
+    /* We already validated our xsdt pointer */
     bios_linker_loader_add_pointer(linker, ACPI_BUILD_RSDP_FILE,
                                    tbl_off + 24, 8,
                                    ACPI_BUILD_TABLE_FILE,
@@ -392,11 +425,6 @@ build_rsdp(GArray *tbl, BIOSLinker *linker, AcpiRsdpData *rsdp_data)
     build_append_int_noprefix(tbl, 0, 1); /* Extended Checksum */
     build_append_int_noprefix(tbl, 0, 3); /* Reserved */
 
-    /* Checksum to be filled by guest linker */
-    bios_linker_loader_add_checksum(linker, ACPI_BUILD_RSDP_FILE,
-                                    tbl_off, 20, /* ACPI rev 1.0 RSDP size */
-                                    8);
-
     /* Extended checksum to be filled by Guest linker */
     bios_linker_loader_add_checksum(linker, ACPI_BUILD_RSDP_FILE,
                                     tbl_off, 36, /* ACPI rev 2.0 RSDP size */