[PATCH v3 5/8] nvdimm acpi: introduce patched dsm memory

[Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>]

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>
---
 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

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