[Qemu-devel] [PULL 27/31] hw: arm: Convert the RSDP build to the buid_append_foo() API

["Michael S. Tsirkin" <mst@redhat.com>]

From: Samuel Ortiz <sameo@linux.intel.com>

Instead of filling a mapped and packed C structure field in random order
and being careful about endianness and sizes, build_rsdp() now uses
build_append_int_noprefix() to compose RSDP table.

This makes reviewing and maintaining code easier as this is almost
matching 1:1 the ACPI spec itself.

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 | 42 ++++++++++++++++++++++------------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index ce8bfa5a37..4a6b53fbfc 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -368,35 +368,39 @@ static void acpi_dsdt_add_power_button(Aml *scope)
 
 /* RSDP */
 static void
-build_rsdp(GArray *rsdp_table, BIOSLinker *linker, AcpiRsdpData *rsdp_data)
+build_rsdp(GArray *tbl, BIOSLinker *linker, AcpiRsdpData *rsdp_data)
 {
-    AcpiRsdpDescriptor *rsdp = acpi_data_push(rsdp_table, sizeof *rsdp);
-    unsigned xsdt_pa_size = sizeof(rsdp->xsdt_physical_address);
-    unsigned xsdt_pa_offset =
-        (char *)&rsdp->xsdt_physical_address - rsdp_table->data;
+    int tbl_off = tbl->len; /* Table offset in the RSDP file */
 
-    bios_linker_loader_alloc(linker, ACPI_BUILD_RSDP_FILE, rsdp_table, 16,
+    bios_linker_loader_alloc(linker, ACPI_BUILD_RSDP_FILE, tbl, 16,
                              true /* fseg memory */);
 
-    memcpy(&rsdp->signature, "RSD PTR ", sizeof(rsdp->signature));
-    memcpy(rsdp->oem_id, rsdp_data->oem_id, sizeof(rsdp->oem_id));
-    rsdp->length = cpu_to_le32(sizeof(*rsdp));
-    rsdp->revision = rsdp_data->revision;
+    g_array_append_vals(tbl, "RSD PTR ", 8); /* Signature */
+    build_append_int_noprefix(tbl, 0, 1); /* Checksum */
+    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 */
+    build_append_int_noprefix(tbl, 36, 4); /* Length */
 
-    /* Address to be filled by Guest linker */
-    bios_linker_loader_add_pointer(linker,
-        ACPI_BUILD_RSDP_FILE, xsdt_pa_offset, xsdt_pa_size,
-        ACPI_BUILD_TABLE_FILE, *rsdp_data->xsdt_tbl_offset);
+    /* XSDT address to be filled by guest linker */
+    build_append_int_noprefix(tbl, 0, 8); /* XsdtAddress */
+    bios_linker_loader_add_pointer(linker, ACPI_BUILD_RSDP_FILE,
+                                   tbl_off + 24, 8,
+                                   ACPI_BUILD_TABLE_FILE,
+                                   *rsdp_data->xsdt_tbl_offset);
 
-    /* Checksum to be filled by Guest linker */
+    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,
-        (char *)rsdp - rsdp_table->data, 20 /* ACPI rev 1.0 RSDP size */,
-        (char *)&rsdp->checksum - rsdp_table->data);
+                                    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,
-        (char *)rsdp - rsdp_table->data, 36 /* ACPI rev 2.0 RSDP size */,
-        (char *)&rsdp->extended_checksum - rsdp_table->data);
+                                    tbl_off, 36, /* ACPI rev 2.0 RSDP size */
+                                    32);
 }
 
 static void
-- 
MST