[Qemu-devel] [PATCH 2/3] acpi: add acpi_table_add_hdr

[Michael S. Tsirkin]

Export a function for magling headers, without updating
the global acpitables blob.

Signed-off-by: Michael S. Tsirkin <address@hidden>
---
 hw/acpi/core.c         | 97 +++++++++++++++++++++++++++++++++++---------------
 include/hw/acpi/acpi.h |  4 +++
 2 files changed, 72 insertions(+), 29 deletions(-)

diff --git a/hw/acpi/core.c b/hw/acpi/core.c
index 64b8718..b76d58c 100644
--- a/hw/acpi/core.c
+++ b/hw/acpi/core.c
@@ -78,27 +78,27 @@ static int acpi_checksum(const uint8_t *data, int len)
     return (-sum) & 0xff;
 }
 
-
-/* Install a copy of the ACPI table specified in @blob.
+/*
+ * Fill an ACPI header in a copy of the ACPI table specified in @blob,
+ * of length @bloblen.
+ * An updated blob is allocated and returned in @out_blob,
+ * updated length in @out_bloblen.
  *
  * If @has_header is set, @blob starts with the System Description Table Header
  * structure. Otherwise, "dfl_hdr" is prepended. In any case, each header field
  * is optionally overwritten from @hdrs.
  *
  * It is valid to call this function with
- * (@blob == NULL && bloblen == 0 && !has_header).
+ * (@blob == NULL && bloblen == 0 &&address@hidden).
  *
  * @hdrs->file and @hdrs->data are ignored.
  *
  * SIZE_MAX is considered "infinity" in this function.
- *
- * The number of tables that can be installed is not limited, but the 16-bit
- * counter at the beginning of "acpi_tables" wraps around after UINT16_MAX.
  */
-static void acpi_table_install(const char unsigned *blob, size_t bloblen,
-                               bool has_header,
-                               const struct AcpiTableOptions *hdrs,
-                               Error **errp)
+int acpi_table_add_hdr(const char unsigned *blob, size_t bloblen,
+                       bool has_header, const struct AcpiTableOptions *hdrs,
+                       char unsigned **out_blob, size_t *out_bloblen,
+                       Error **errp)
 {
     size_t body_start;
     const char unsigned *hdr_src;
@@ -124,7 +124,7 @@ static void acpi_table_install(const char unsigned *blob, 
size_t bloblen,
             error_setg(errp, "ACPI table claiming to have header is too "
                        "short, available: %zu, expected: %zu", bloblen,
                        body_start);
-            return;
+            return -1;
         }
         hdr_src = blob;
     } else {
@@ -145,33 +145,29 @@ static void acpi_table_install(const char unsigned *blob, 
size_t bloblen,
     if (acpi_payload_size > UINT16_MAX) {
         error_setg(errp, "ACPI table too big, requested: %zu, max: %u",
                    acpi_payload_size, (unsigned)UINT16_MAX);
-        return;
-    }
-
-    /* We won't fail from here on. Initialize / extend the globals. */
-    if (acpi_tables == NULL) {
-        acpi_tables_len = sizeof(uint16_t);
-        acpi_tables = g_malloc0(acpi_tables_len);
+        return -1;
     }
 
-    acpi_tables = g_realloc(acpi_tables, acpi_tables_len +
-                                         ACPI_TABLE_PFX_SIZE +
-                                         sizeof dfl_hdr + body_size);
+    /* We won't fail from here on. Allocate memory. */
+    *out_bloblen = sizeof(uint16_t);
+    *out_blob = g_malloc0(*out_bloblen +
+                          ACPI_TABLE_PFX_SIZE +
+                          sizeof dfl_hdr + body_size);
 
-    ext_hdr = (struct acpi_table_header *)(acpi_tables + acpi_tables_len);
-    acpi_tables_len += ACPI_TABLE_PFX_SIZE;
+    ext_hdr = (struct acpi_table_header *)(*out_blob + *out_bloblen);
+    *out_bloblen += ACPI_TABLE_PFX_SIZE;
 
-    memcpy(acpi_tables + acpi_tables_len, hdr_src, sizeof dfl_hdr);
-    acpi_tables_len += sizeof dfl_hdr;
+    memcpy(*out_blob + *out_bloblen, hdr_src, sizeof dfl_hdr);
+    *out_bloblen += sizeof dfl_hdr;
 
     if (blob != NULL) {
-        memcpy(acpi_tables + acpi_tables_len, blob + body_start, body_size);
-        acpi_tables_len += body_size;
+        memcpy(*out_blob + *out_bloblen, blob + body_start, body_size);
+        *out_bloblen += body_size;
     }
 
     /* increase number of tables */
-    cpu_to_le16wu((uint16_t *)acpi_tables,
-                  le16_to_cpupu((uint16_t *)acpi_tables) + 1u);
+    cpu_to_le16wu((uint16_t *)*out_blob,
+                  le16_to_cpupu((uint16_t *)*out_blob) + 1u);
 
     /* Update the header fields. The strings need not be NUL-terminated. */
     changed_fields = 0;
@@ -227,6 +223,49 @@ static void acpi_table_install(const char unsigned *blob, 
size_t bloblen,
     /* recalculate checksum */
     ext_hdr->checksum = acpi_checksum((const char unsigned *)ext_hdr +
                                       ACPI_TABLE_PFX_SIZE, acpi_payload_size);
+    return 0;
+}
+
+/* Install a copy of the ACPI table specified in @blob.
+ *
+ * If @has_header is set, @blob starts with the System Description Table Header
+ * structure. Otherwise, "dfl_hdr" is prepended. In any case, each header field
+ * is optionally overwritten from @hdrs.
+ *
+ * It is valid to call this function with
+ * (@blob == NULL && bloblen == 0 && !has_header).
+ *
+ * @hdrs->file and @hdrs->data are ignored.
+ *
+ * SIZE_MAX is considered "infinity" in this function.
+ *
+ * The number of tables that can be installed is not limited, but the 16-bit
+ * counter at the beginning of "acpi_tables" wraps around after UINT16_MAX.
+ */
+void acpi_table_install(const char unsigned *blob, size_t bloblen,
+                        bool has_header, const struct AcpiTableOptions *hdrs,
+                        Error **errp)
+{
+    char unsigned *out_blob;
+    size_t out_bloblen;
+    int r;
+
+    r = acpi_table_add_hdr(blob, bloblen, has_header, hdrs,
+                           &out_blob, &out_bloblen, errp);
+    if (r < 0) {
+        return;
+    }
+
+    /* We won't fail from here on. Initialize / extend the globals. */
+    if (acpi_tables == NULL) {
+        acpi_tables_len = sizeof(uint16_t);
+        acpi_tables = g_malloc0(acpi_tables_len);
+    }
+
+    acpi_tables = g_realloc(acpi_tables, acpi_tables_len + out_bloblen);
+    memcpy(acpi_tables + acpi_tables_len, out_blob, out_bloblen);
+    acpi_tables_len += out_bloblen;
+    g_free(out_blob);
 }
 
 void acpi_table_add(const QemuOpts *opts, Error **errp)
diff --git a/include/hw/acpi/acpi.h b/include/hw/acpi/acpi.h
index 80e955d..35f7e09 100644
--- a/include/hw/acpi/acpi.h
+++ b/include/hw/acpi/acpi.h
@@ -159,6 +159,10 @@ extern int acpi_enabled;
 extern char unsigned *acpi_tables;
 extern size_t acpi_tables_len;
 
+int acpi_table_add_hdr(const char unsigned *blob, size_t bloblen,
+                       bool has_header, const struct AcpiTableOptions *hdrs,
+                       char unsigned **out_blob, size_t *out_bloblen,
+                       Error **errp);
 void acpi_table_install(const char unsigned *blob, size_t bloblen,
                         bool has_header, const struct AcpiTableOptions *hdrs,
                         Error **errp);
-- 
MST