[Xen-devel] [PATCH v5 05/24] hw: acpi: Implement XSDT support for RSDP

[Samuel Ortiz <sameo@xxxxxxxxxxxxxxx>]

XSDT is the 64-bit version of the legacy ACPI RSDT (Root System
Description Table). RSDT only allow for 32-bit addressses and have thus
been deprecated. Since ACPI version 2.0, RSDPs should point at XSDTs and
no longer RSDTs, although RSDTs are still supported for backward
compatibility.

Since version 2.0, RSDPs should add an extended checksum, a complete table
length and a version field to the table.

Signed-off-by: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx>
---
 include/hw/acpi/aml-build.h |  3 +++
 hw/acpi/aml-build.c         | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
index c9bcb32d81..3580d0ce90 100644
--- a/include/hw/acpi/aml-build.h
+++ b/include/hw/acpi/aml-build.h
@@ -393,6 +393,9 @@ void
 build_rsdp(GArray *table_data,
            BIOSLinker *linker, unsigned rsdt_tbl_offset);
 void
+build_rsdp_xsdt(GArray *table_data,
+                BIOSLinker *linker, unsigned xsdt_tbl_offset);
+void
 build_rsdt(GArray *table_data, BIOSLinker *linker, GArray *table_offsets,
            const char *oem_id, const char *oem_table_id);
 void
diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index 51b608432f..a030d40674 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -1651,6 +1651,43 @@ build_xsdt(GArray *table_data, BIOSLinker *linker, 
GArray *table_offsets,
                  (void *)xsdt, "XSDT", xsdt_len, 1, oem_id, oem_table_id);
 }
 
+/* RSDP pointing at an XSDT */
+void
+build_rsdp_xsdt(GArray *rsdp_table,
+                BIOSLinker *linker, unsigned xsdt_tbl_offset)
+{
+    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;
+    unsigned xsdt_offset =
+        (char *)&rsdp->length - rsdp_table->data;
+
+    bios_linker_loader_alloc(linker, ACPI_BUILD_RSDP_FILE, rsdp_table, 16,
+                             true /* fseg memory */);
+
+    memcpy(&rsdp->signature, "RSD PTR ", 8);
+    memcpy(rsdp->oem_id, ACPI_BUILD_APPNAME6, 6);
+    rsdp->length = cpu_to_le32(sizeof(*rsdp));
+    /* version 2, we will use the XSDT pointer */
+    rsdp->revision = 0x02;
+
+    /* 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, xsdt_tbl_offset);
+
+    /* Legacy checksum to be filled by Guest linker */
+    bios_linker_loader_add_checksum(linker, ACPI_BUILD_RSDP_FILE,
+        (char *)rsdp - rsdp_table->data, xsdt_offset,
+        (char *)&rsdp->checksum - rsdp_table->data);
+
+    /* Extended checksum to be filled by Guest linker */
+    bios_linker_loader_add_checksum(linker, ACPI_BUILD_RSDP_FILE,
+        (char *)rsdp - rsdp_table->data, sizeof *rsdp,
+        (char *)&rsdp->extended_checksum - rsdp_table->data);
+}
+
 void build_srat_memory(AcpiSratMemoryAffinity *numamem, uint64_t base,
                        uint64_t len, int node, MemoryAffinityFlags flags)
 {
-- 
2.19.1


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