[Qemu-devel] [PATCH RFC 1/3] loader: support for unmapped ROM blobs

["Michael S. Tsirkin" <mst@redhat.com>]

Support ROM blobs not mapped into guest memory:
let user pass in MR for memory serving as the backing store.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/core/loader.c       | 32 +++++++++++++++++++++++++++++---
 hw/lm32/lm32_hwsetup.h |  2 +-
 include/hw/loader.h    |  4 ++--
 3 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/hw/core/loader.c b/hw/core/loader.c
index a711145..ac62454 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -542,6 +542,7 @@ struct Rom {
     size_t datasize;
 
     uint8_t *data;
+    MemoryRegion *mr;
     int isrom;
     char *fw_dir;
     char *fw_file;
@@ -641,7 +642,7 @@ err:
 }
 
 int rom_add_blob(const char *name, const void *blob, size_t len,
-                 hwaddr addr)
+                 hwaddr addr, MemoryRegion *mr)
 {
     Rom *rom;
 
@@ -651,6 +652,11 @@ int rom_add_blob(const char *name, const void *blob, size_t len,
     rom->romsize  = len;
     rom->datasize = len;
     rom->data     = g_malloc0(rom->datasize);
+    rom->mr       = mr;
+    if (mr) {
+        assert(memory_region_is_ram(mr));
+        rom->isrom = memory_region_is_rom(mr);
+    }
     memcpy(rom->data, blob, len);
     rom_insert(rom);
     return 0;
@@ -697,7 +703,12 @@ static void rom_reset(void *unused)
         if (rom->data == NULL) {
             continue;
         }
-        cpu_physical_memory_write_rom(rom->addr, rom->data, rom->datasize);
+        if (rom->mr) {
+            void *host = memory_region_get_ram_ptr(rom->mr);
+            memcpy(host, rom->data, rom->datasize);
+        } else {
+            cpu_physical_memory_write_rom(rom->addr, rom->data, rom->datasize);
+        }
         if (rom->isrom) {
             /* rom needs to be written only once */
             g_free(rom->data);
@@ -713,6 +724,9 @@ int rom_load_all(void)
     Rom *rom;
 
     QTAILQ_FOREACH(rom, &roms, next) {
+        if (rom->mr) {
+            continue;
+        }
         if (rom->fw_file) {
             continue;
         }
@@ -746,6 +760,9 @@ static Rom *find_rom(hwaddr addr)
         if (rom->fw_file) {
             continue;
         }
+        if (rom->mr) {
+            continue;
+        }
         if (rom->addr > addr) {
             continue;
         }
@@ -773,6 +790,9 @@ int rom_copy(uint8_t *dest, hwaddr addr, size_t size)
         if (rom->fw_file) {
             continue;
         }
+        if (rom->mr) {
+            continue;
+        }
         if (rom->addr + rom->romsize < addr) {
             continue;
         }
@@ -832,7 +852,13 @@ void do_info_roms(Monitor *mon, const QDict *qdict)
     Rom *rom;
 
     QTAILQ_FOREACH(rom, &roms, next) {
-        if (!rom->fw_file) {
+        if (rom->mr) {
+            monitor_printf(mon, "%s"
+                           " size=0x%06zx name=\"%s\"\n",
+                           rom->mr->name,
+                           rom->romsize,
+                           rom->name);
+        } else if (!rom->fw_file) {
             monitor_printf(mon, "addr=" TARGET_FMT_plx
                            " size=0x%06zx mem=%s name=\"%s\"\n",
                            rom->addr, rom->romsize,
diff --git a/hw/lm32/lm32_hwsetup.h b/hw/lm32/lm32_hwsetup.h
index 3449bd8..d6914d6 100644
--- a/hw/lm32/lm32_hwsetup.h
+++ b/hw/lm32/lm32_hwsetup.h
@@ -73,7 +73,7 @@ static inline void hwsetup_free(HWSetup *hw)
 static inline void hwsetup_create_rom(HWSetup *hw,
         hwaddr base)
 {
-    rom_add_blob("hwsetup", hw->data, TARGET_PAGE_SIZE, base);
+    rom_add_blob("hwsetup", hw->data, TARGET_PAGE_SIZE, base, NULL);
 }
 
 static inline void hwsetup_add_u8(HWSetup *hw, uint8_t u)
diff --git a/include/hw/loader.h b/include/hw/loader.h
index 15d4cc9..b39e7d1 100644
--- a/include/hw/loader.h
+++ b/include/hw/loader.h
@@ -27,7 +27,7 @@ void pstrcpy_targphys(const char *name,
 int rom_add_file(const char *file, const char *fw_dir,
                  hwaddr addr, int32_t bootindex);
 int rom_add_blob(const char *name, const void *blob, size_t len,
-                 hwaddr addr);
+                 hwaddr addr, MemoryRegion *mr);
 int rom_add_elf_program(const char *name, void *data, size_t datasize,
                         size_t romsize, hwaddr addr);
 int rom_load_all(void);
@@ -39,7 +39,7 @@ void do_info_roms(Monitor *mon, const QDict *qdict);
 #define rom_add_file_fixed(_f, _a, _i)          \
     rom_add_file(_f, NULL, _a, _i)
 #define rom_add_blob_fixed(_f, _b, _l, _a)      \
-    rom_add_blob(_f, _b, _l, _a)
+    rom_add_blob(_f, _b, _l, _a, NULL)
 
 #define PC_ROM_MIN_VGA     0xc0000
 #define PC_ROM_MIN_OPTION  0xc8000
-- 
MST