From: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
This is a very limited form of support for runtime patching -
similar in functionality to what we can do with ACPI_EXTRACT
macros in python, but implemented in C.
This is to allow ACPI code direct access to data tables -
which is exactly what DataTableRegion is there for, except
no known windows release so far implements DataTableRegion.
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
---
hw/acpi/aml-build.c | 28 ++++++++++++++++++++++++++++
include/hw/acpi/aml-build.h | 3 +++
2 files changed, 31 insertions(+)
diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index f26fa26..ab89ca6 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -258,6 +258,34 @@ static void build_append_int(GArray *table, uint64_t value)
}
}
+/*
+ * Build NAME(XXXX, 0x00000000) where 0x00000000 is encoded as a dword,
+ * and return the offset to 0x00000000 for runtime patching.
+ *
+ * Warning: runtime patching is best avoided. Only use this as
+ * a replacement for DataTableRegion (for guests that don't
+ * support it).
+ */
+int
+build_append_named_dword(GArray *array, const char *name_format, ...)
+{
+ int offset;
+ va_list ap;
+
+ build_append_byte(array, 0x08); /* NameOp */
+ va_start(ap, name_format);
+ build_append_namestringv(array, name_format, ap);
+ va_end(ap);
+
+ build_append_byte(array, 0x0C); /* DWordPrefix */
+
+ offset = array->len;
+ build_append_int_noprefix(array, 0x00000000, 4);
+ assert(array->len == offset + 4);
+
+ return offset;
+}
+
static GPtrArray *alloc_list;
static Aml *aml_alloc(void)
diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
index 07b2d48..7404e2a 100644
--- a/include/hw/acpi/aml-build.h
+++ b/include/hw/acpi/aml-build.h
@@ -370,4 +370,7 @@ void
build_rsdt(GArray *table_data, GArray *linker, GArray *table_offsets,
const char *oem_id, const char *oem_table_id);
+int
+build_append_named_dword(GArray *array, const char *name_format, ...);
+
#endif
--
1.8.3.1
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