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-rw-r--r--exec.c44
-rw-r--r--hw/core/loader.c7
-rw-r--r--include/exec/cpu-common.h1
3 files changed, 47 insertions, 5 deletions
diff --git a/exec.c b/exec.c
index 00526d18c0..7e49e8e555 100644
--- a/exec.c
+++ b/exec.c
@@ -50,6 +50,7 @@
 #include "translate-all.h"
 
 #include "exec/memory-internal.h"
+#include "qemu/cache-utils.h"
 
 #include "qemu/range.h"
 
@@ -2070,9 +2071,13 @@ void cpu_physical_memory_rw(hwaddr addr, uint8_t *buf,
     address_space_rw(&address_space_memory, addr, buf, len, is_write);
 }
 
-/* used for ROM loading : can write in RAM and ROM */
-void cpu_physical_memory_write_rom(hwaddr addr,
-                                   const uint8_t *buf, int len)
+enum write_rom_type {
+    WRITE_DATA,
+    FLUSH_CACHE,
+};
+
+static inline void cpu_physical_memory_write_rom_internal(
+    hwaddr addr, const uint8_t *buf, int len, enum write_rom_type type)
 {
     hwaddr l;
     uint8_t *ptr;
@@ -2091,8 +2096,15 @@ void cpu_physical_memory_write_rom(hwaddr addr,
             addr1 += memory_region_get_ram_addr(mr);
             /* ROM/RAM case */
             ptr = qemu_get_ram_ptr(addr1);
-            memcpy(ptr, buf, l);
-            invalidate_and_set_dirty(addr1, l);
+            switch (type) {
+            case WRITE_DATA:
+                memcpy(ptr, buf, l);
+                invalidate_and_set_dirty(addr1, l);
+                break;
+            case FLUSH_CACHE:
+                flush_icache_range((uintptr_t)ptr, (uintptr_t)ptr + l);
+                break;
+            }
         }
         len -= l;
         buf += l;
@@ -2100,6 +2112,28 @@ void cpu_physical_memory_write_rom(hwaddr addr,
     }
 }
 
+/* used for ROM loading : can write in RAM and ROM */
+void cpu_physical_memory_write_rom(hwaddr addr,
+                                   const uint8_t *buf, int len)
+{
+    cpu_physical_memory_write_rom_internal(addr, buf, len, WRITE_DATA);
+}
+
+void cpu_flush_icache_range(hwaddr start, int len)
+{
+    /*
+     * This function should do the same thing as an icache flush that was
+     * triggered from within the guest. For TCG we are always cache coherent,
+     * so there is no need to flush anything. For KVM / Xen we need to flush
+     * the host's instruction cache at least.
+     */
+    if (tcg_enabled()) {
+        return;
+    }
+
+    cpu_physical_memory_write_rom_internal(start, NULL, len, FLUSH_CACHE);
+}
+
 typedef struct {
     MemoryRegion *mr;
     void *buffer;
diff --git a/hw/core/loader.c b/hw/core/loader.c
index 60d2ebd4ac..0634bee20c 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -785,6 +785,13 @@ static void rom_reset(void *unused)
             g_free(rom->data);
             rom->data = NULL;
         }
+        /*
+         * The rom loader is really on the same level as firmware in the guest
+         * shadowing a ROM into RAM. Such a shadowing mechanism needs to ensure
+         * that the instruction cache for that new region is clear, so that the
+         * CPU definitely fetches its instructions from the just written data.
+         */
+        cpu_flush_icache_range(rom->addr, rom->datasize);
     }
 }
 
diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index e4996e19c3..8f33122c9f 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -110,6 +110,7 @@ void stq_phys(hwaddr addr, uint64_t val);
 
 void cpu_physical_memory_write_rom(hwaddr addr,
                                    const uint8_t *buf, int len);
+void cpu_flush_icache_range(hwaddr start, int len);
 
 extern struct MemoryRegion io_mem_rom;
 extern struct MemoryRegion io_mem_notdirty;