[PATCH 8/9] nvdimm acpi: emulate dsm method

[Xiao Guangrong <guangrong.xiao@linux.intel.com>]

Emulate dsm method after IO VM-exit

Currently, we only introduce the framework and no function is actually
supported

Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
---
 hw/acpi/aml-build.c         |  2 +-
 hw/acpi/nvdimm.c            | 44 ++++++++++++++++++++++++++++++++++++++++++++
 include/hw/acpi/aml-build.h |  1 +
 include/hw/mem/nvdimm.h     |  8 ++++++++
 4 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index ab89ca6..da11bf8 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -227,7 +227,7 @@ static void build_extop_package(GArray *package, uint8_t op)
     build_prepend_byte(package, 0x5B); /* ExtOpPrefix */
 }
 
-static void build_append_int_noprefix(GArray *table, uint64_t value, int size)
+void build_append_int_noprefix(GArray *table, uint64_t value, int size)
 {
     int i;
 
diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
index 781f6c1..e0b483a 100644
--- a/hw/acpi/nvdimm.c
+++ b/hw/acpi/nvdimm.c
@@ -393,12 +393,56 @@ typedef struct NvdimmDsmOut NvdimmDsmOut;
 static uint64_t
 nvdimm_dsm_read(void *opaque, hwaddr addr, unsigned size)
 {
+    fprintf(stderr, "BUG: we never read _DSM IO Port.\n");
     return 0;
 }
 
 static void
 nvdimm_dsm_write(void *opaque, hwaddr addr, uint64_t val, unsigned size)
 {
+    NvdimmDsmIn *in;
+    GArray *out;
+    uint32_t buf_size;
+    hwaddr dsm_mem_addr = val;
+
+    nvdimm_debug("dsm memory address %#lx.\n", dsm_mem_addr);
+
+    /*
+     * The DSM memory is mapped to guest address space so an evil guest
+     * can change its content while we are doing DSM emulation. Avoid
+     * this by copying DSM memory to QEMU local memory.
+     */
+    in = g_malloc(TARGET_PAGE_SIZE);
+    cpu_physical_memory_read(dsm_mem_addr, in, TARGET_PAGE_SIZE);
+
+    le32_to_cpus(&in->revision);
+    le32_to_cpus(&in->function);
+    le32_to_cpus(&in->handle);
+
+    nvdimm_debug("Revision %#x Handler %#x Function %#x.\n", in->revision,
+                 in->handle, in->function);
+
+    out = g_array_new(false, true /* clear */, 1);
+
+    /*
+     * function 0 is called to inquire what functions are supported by
+     * OSPM
+     */
+    if (in->function == 0) {
+        build_append_int_noprefix(out, 0 /* No function Supported */,
+                                  sizeof(uint8_t));
+    } else {
+        /* No function is supported yet. */
+        build_append_int_noprefix(out, 1 /* Not Supported */,
+                                  sizeof(uint8_t));
+    }
+
+    buf_size = cpu_to_le32(out->len);
+    cpu_physical_memory_write(dsm_mem_addr, &buf_size, sizeof(buf_size));
+    cpu_physical_memory_write(dsm_mem_addr + sizeof(buf_size), out->data,
+                              out->len);
+    g_free(in);
+    g_array_free(out, true);
 }
 
 static const MemoryRegionOps nvdimm_dsm_ops = {
diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
index 7404e2a..b0826f0 100644
--- a/include/hw/acpi/aml-build.h
+++ b/include/hw/acpi/aml-build.h
@@ -357,6 +357,7 @@ Aml *aml_derefof(Aml *arg);
 Aml *aml_sizeof(Aml *arg);
 Aml *aml_concatenate(Aml *source1, Aml *source2, Aml *target);
 
+void build_append_int_noprefix(GArray *table, uint64_t value, int size);
 void
 build_header(GArray *linker, GArray *table_data,
              AcpiTableHeader *h, const char *sig, int len, uint8_t rev,
diff --git a/include/hw/mem/nvdimm.h b/include/hw/mem/nvdimm.h
index 634c60b..aaa2608 100644
--- a/include/hw/mem/nvdimm.h
+++ b/include/hw/mem/nvdimm.h
@@ -25,6 +25,14 @@
 
 #include "hw/mem/pc-dimm.h"
 
+#define NVDIMM_DEBUG 0
+#define nvdimm_debug(fmt, ...)                                \
+    do {                                                      \
+        if (NVDIMM_DEBUG) {                                   \
+            fprintf(stderr, "nvdimm: " fmt, ## __VA_ARGS__);  \
+        }                                                     \
+    } while (0)
+
 #define TYPE_NVDIMM             "nvdimm"
 
 #define NVDIMM_DSM_MEM_FILE     "etc/acpi/nvdimm-mem"
-- 
1.8.3.1