[v2,11/22] hw/core/loader: Add ROM loader notifier

Commit Message

Jean-Philippe Brucker April 19, 2024, 3:56 p.m. UTC

Add a function to register a notifier, that is invoked after a ROM gets
loaded into guest memory.

It will be used by Arm confidential guest support, in order to register
all blobs loaded into memory with KVM, so that their content is part of
the initial VM measurement and contribute to the guest attestation.

Signed-off-by: Jean-Philippe Brucker <[e-mail]>
---
v1->v2: new
---
 include/hw/loader.h | 15 +++++++++++++++
 hw/core/loader.c    | 15 +++++++++++++++
 2 files changed, 30 insertions(+)

Patch

diff --git a/include/hw/loader.h b/include/hw/loader.h
index 8685e27334..79fab25dd9 100644
--- a/include/hw/loader.h
+++ b/include/hw/loader.h
@@ -356,6 +356,21 @@  void hmp_info_roms(Monitor *mon, const QDict *qdict);
 ssize_t rom_add_vga(const char *file);
 ssize_t rom_add_option(const char *file, int32_t bootindex);
 
+typedef struct RomLoaderNotify {
+    /* Parameters passed to rom_add_blob() */
+    hwaddr addr;
+    size_t len;
+    size_t max_len;
+} RomLoaderNotify;
+
+/**
+ * rom_add_load_notifier - Add a notifier for loaded images
+ *
+ * Add a notifier that will be invoked with a RomLoaderNotify structure for each
+ * blob loaded into guest memory, after the blob is loaded.
+ */
+void rom_add_load_notifier(Notifier *notifier);
+
 /* This is the usual maximum in uboot, so if a uImage overflows this, it would
  * overflow on real hardware too. */
 #define UBOOT_MAX_GUNZIP_BYTES (64 << 20)
diff --git a/hw/core/loader.c b/hw/core/loader.c
index b8e52f3fb0..4bd236cf89 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -67,6 +67,8 @@ 
 #include <zlib.h>
 
 static int roms_loaded;
+static NotifierList rom_loader_notifier =
+    NOTIFIER_LIST_INITIALIZER(rom_loader_notifier);
 
 /* return the size or -1 if error */
 int64_t get_image_size(const char *filename)
@@ -1209,6 +1211,11 @@  MemoryRegion *rom_add_blob(const char *name, const void *blob, size_t len,
     return mr;
 }
 
+void rom_add_load_notifier(Notifier *notifier)
+{
+    notifier_list_add(&rom_loader_notifier, notifier);
+}
+
 /* This function is specific for elf program because we don't need to allocate
  * all the rom. We just allocate the first part and the rest is just zeros. This
  * is why romsize and datasize are different. Also, this function takes its own
@@ -1250,6 +1257,7 @@  ssize_t rom_add_option(const char *file, int32_t bootindex)
 static void rom_reset(void *unused)
 {
     Rom *rom;
+    RomLoaderNotify notify;
 
     QTAILQ_FOREACH(rom, &roms, next) {
         if (rom->fw_file) {
@@ -1298,6 +1306,13 @@  static void rom_reset(void *unused)
         cpu_flush_icache_range(rom->addr, rom->datasize);
 
         trace_loader_write_rom(rom->name, rom->addr, rom->datasize, rom->isrom);
+
+        notify = (RomLoaderNotify) {
+            .addr = rom->addr,
+            .len = rom->datasize,
+            .max_len = rom->romsize,
+        };
+        notifier_list_notify(&rom_loader_notifier, &notify);
     }
 }