On Sun, Feb 14, 2016 at 04:51:02PM +0800, Xiao Guangrong wrote:
> The dsm memory is used to save the input parameters and store
> the dsm result which is filled by QEMU.
>
> The address of dsm memory is decided by bios and patched into
> int32 object named "MEMA"
>
> Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
This is a bit too hacky for my taste. First, I would prefer an explicit API
to add a DWORD. Second, I would like to avoid offset math hacks
and make API returning offsets.
Pls see below for a suggestion.
> ---
> hw/acpi/nvdimm.c | 34 +++++++++++++++++++++++++++++++++-
> 1 file changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
> index 8568b20..bca36ae 100644
> --- a/hw/acpi/nvdimm.c
> +++ b/hw/acpi/nvdimm.c
> @@ -29,6 +29,7 @@
> #include "qemu/osdep.h"
> #include "hw/acpi/acpi.h"
> #include "hw/acpi/aml-build.h"
> +#include "hw/acpi/bios-linker-loader.h"
> #include "hw/nvram/fw_cfg.h"
> #include "hw/mem/nvdimm.h"
>
> @@ -406,6 +407,7 @@ void nvdimm_init_acpi_state(AcpiNVDIMMState *state, MemoryRegion *io,
> }
>
> #define NVDIMM_COMMON_DSM "NCAL"
> +#define NVDIMM_ACPI_MEM_ADDR "MEMA"
>
> static void nvdimm_build_common_dsm(Aml *dev)
> {
> @@ -470,7 +472,9 @@ static void nvdimm_build_nvdimm_devices(GSList *device_list, Aml *root_dev)
> static void nvdimm_build_ssdt(GSList *device_list, GArray *table_offsets,
> GArray *table_data, GArray *linker)
> {
> - Aml *ssdt, *sb_scope, *dev;
> + Aml *ssdt, *sb_scope, *dev, *mem_addr;
> + uint32_t zero_offset = 0;
> + int offset;
>
> acpi_add_table(table_offsets, table_data);
>
> @@ -501,9 +505,37 @@ static void nvdimm_build_ssdt(GSList *device_list, GArray *table_offsets,
>
> aml_append(sb_scope, dev);
>
> + /*
> + * leave it at the end of ssdt so that we can conveniently get the
> + * offset of int32 object which will be patched with the real address
> + * of the dsm memory by BIOS.
> + *
> + * 0x32000000 is the magic number to let aml_int() create int32 object.
> + * It will be zeroed later to make bios_linker_loader_add_pointer()
> + * happy.
> + */
> + mem_addr = aml_name_decl(NVDIMM_ACPI_MEM_ADDR, aml_int(0x32000000));
> +
> + aml_append(sb_scope, mem_addr);
> aml_append(ssdt, sb_scope);
> /* copy AML table into ACPI tables blob and patch header there */
> g_array_append_vals(table_data, ssdt->buf->data, ssdt->buf->len);
> +
> + offset = table_data->len - 4;
> +
> + /*
> + * zero the last 4 bytes, i.e, it is the offset of
> + * NVDIMM_ACPI_MEM_ADDR object.
> + */
> + g_array_remove_range(table_data, offset, 4);
> + g_array_append_vals(table_data, &zero_offset, 4);
> +
> + bios_linker_loader_alloc(linker, NVDIMM_DSM_MEM_FILE, TARGET_PAGE_SIZE,
> + false /* high memory */);
> + bios_linker_loader_add_pointer(linker, ACPI_BUILD_TABLE_FILE,
> + NVDIMM_DSM_MEM_FILE, table_data,
> + table_data->data + offset,
> + sizeof(uint32_t));
> build_header(linker, table_data,
> (void *)(table_data->data + table_data->len - ssdt->buf->len),
> "SSDT", ssdt->buf->len, 1, NULL, "NVDIMM");
> --
> 1.8.3.1
--->
acpi: add build_append_named_dword, returning an offset in buffer
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>
---
diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
index 1b632dc..f8998ea 100644
--- a/include/hw/acpi/aml-build.h
+++ b/include/hw/acpi/aml-build.h
@@ -286,4 +286,7 @@ void acpi_build_tables_cleanup(AcpiBuildTables *tables, bool mfre);
void
build_rsdt(GArray *table_data, GArray *linker, GArray *table_offsets);
+int
+build_append_named_dword(GArray *array, const char *name_format, ...);
+
#endif
diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index 0d4b324..7f9fa65 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -262,6 +262,32 @@ 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;
+
+ 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)
--
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