When enabling write access to 0xf0000, just copy from 0xffff0000.

Instead of copying the bios to temp space and then copying back to
    0xf0000, just copy from the permanent location at 0xffff0000.
This should make startup slightly faster.

diff --git a/TODO b/TODO
index 0fa1663acc6019a0e4d5592537f766b38f57d652..45ffe1d98946b11f41fa608998a83f378d233c8d 100644 (file)
--- a/TODO
+++ b/TODO
@@ -1,6 +1,5 @@
 Enhance shadow support: Write-enable c, d, e segments; write protect
-option roms before boot.  When copying bios - just copy from high
-memory.
+option roms before boot.
 
 Replace hand-rolled memory allocation code with new malloc_fseg() and
 malloc_high() functions.

diff --git a/src/config.h b/src/config.h
index a77fe0c10f2baf7ec8cebb11c196fe09b8979ede..cba7ac4b07e6580f849d79e0f323b9c488fe6434 100644 (file)
--- a/src/config.h
+++ b/src/config.h
@@ -114,8 +114,6 @@
 #define BUILD_AP_BOOT_ADDR        0x10000
 #define BUILD_BIOS_ADDR           0xf0000
 #define BUILD_BIOS_SIZE           0x10000
-// 64 KB used to copy the BIOS to shadow RAM
-#define BUILD_BIOS_TMP_ADDR       0x30000
 
 #define BUILD_APIC_ADDR           0xfee00000
 #define BUILD_IOAPIC_ADDR         0xfec00000

diff --git a/src/shadow.c b/src/shadow.c
index 264656d1ceb720998eb1fc2c0fda50a5d5cd6f15..1c389f44a44d74b3499d453e9d58f2c8cdc76339 100644 (file)
--- a/src/shadow.c
+++ b/src/shadow.c
@@ -18,15 +18,15 @@
             (__addr - __start < __size); \
         })
 
+// On the emulators, the bios at 0xf0000 is also at 0xffff0000
+#define BIOS_SRC_ADDR 0xffff0000
+
 // Enable shadowing and copy bios.
 static void
-copy_bios(u16 bdf)
+copy_bios(u16 bdf, int reg)
 {
-    int v = pci_config_readb(bdf, 0x59);
-    v |= 0x30;
-    pci_config_writeb(bdf, 0x59, v);
-    memcpy((void *)BUILD_BIOS_ADDR, (void *)BUILD_BIOS_TMP_ADDR
-           , BUILD_BIOS_SIZE);
+    pci_config_writeb(bdf, 0x59, reg | 0x30);
+    memcpy((void*)BUILD_BIOS_ADDR, (void*)BIOS_SRC_ADDR, BUILD_BIOS_SIZE);
 }
 
 // Make the BIOS code segment area (0xf0000) writable.
@@ -45,24 +45,24 @@ make_bios_writable()
         return;
     }
 
-    // Copy the bios to a temporary area.
-    memcpy((void *)BUILD_BIOS_TMP_ADDR, (void *)BUILD_BIOS_ADDR
-           , BUILD_BIOS_SIZE);
+    int reg = pci_config_readb(bdf, 0x59);
+    if (reg & 0x30) {
+        // Ram already present - just enable writes
+        pci_config_writeb(bdf, 0x59, reg | 0x30);
+        return;
+    }
 
     // Enable shadowing and copy bios.
     if (IN_RANGE((u32)copy_bios, BUILD_BIOS_ADDR, BUILD_BIOS_SIZE)) {
         // Jump to shadow enable function - use the copy in the
         // temporary storage area so that memory does not change under
         // the executing code.
-        u32 pos = (u32)copy_bios - BUILD_BIOS_ADDR + BUILD_BIOS_TMP_ADDR;
-        void (*func)(u16 bdf) = (void*)pos;
-        func(bdf);
+        u32 pos = (u32)copy_bios - BUILD_BIOS_ADDR + BIOS_SRC_ADDR;
+        void (*func)(u16 bdf, int reg) = (void*)pos;
+        func(bdf, reg);
     } else {
-        copy_bios(bdf);
+        copy_bios(bdf, reg);
     }
-
-    // Clear the temporary area.
-    memset((void *)BUILD_BIOS_TMP_ADDR, 0, BUILD_BIOS_SIZE);
 }
 
 // Make the BIOS code segment area (0xf0000) read-only.