Defer copying VBIOS to low memory until later, similar to the CSM

Author: mintsuki

src/csmwrap.c

@@ -229,6 +229,7 @@ EFI_STATUS efi_main(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
 
     /* Copy ROM to location, as late as possible */
     memcpy((void*)csm_bin_base, Csm16_bin, sizeof(Csm16_bin));
+    memcpy((void*)VGABIOS_START, vbios_loc, vbios_size);
 
     memset(&Regs, 0, sizeof(EFI_IA32_REGISTER_SET));
     Regs.X.AX = Legacy16InitializeYourself;

src/csmwrap.h

@@ -45,6 +45,9 @@ extern int copy_rsdt(struct csmwrap_priv *priv);
 int build_e820_map(struct csmwrap_priv *priv);
 int apply_intel_platform_workarounds(void);
 
+extern void *vbios_loc;
+extern uintptr_t vbios_size;
+
 
 static inline int
 efi_guidcmp (EFI_GUID left, EFI_GUID right)

src/video.c

@@ -5,6 +5,9 @@
 // Generated by: xxd -i vgabios.bin >> vgabios.h
 #include "bins/vgabios.h"
 
+void *vbios_loc;
+uintptr_t vbios_size;
+
 static EFI_STATUS FindGopPciDevice(struct csmwrap_priv *priv)
 {
     EFI_STATUS                   Status = EFI_SUCCESS;
@@ -386,7 +389,8 @@ EFI_STATUS csmwrap_video_oprom_init(struct csmwrap_priv *priv)
         return Status;
     }
 
-    memcpy((void*)VGABIOS_START, LocalRomImage, LocalRomSize);
+    vbios_loc = LocalRomImage;
+    vbios_size = LocalRomSize;
 
     priv->video_type = CSMWRAP_VIDEO_OPROM;
 
@@ -493,8 +497,8 @@ EFI_STATUS csmwrap_video_seavgabios_init(struct csmwrap_priv *priv)
             return EFI_UNSUPPORTED;
     }
 
-    /* Copy VGA BIOS to location */
-    memcpy((void*)VGABIOS_START, vgabios_bin, sizeof(vgabios_bin));
+    vbios_loc = vgabios_bin;
+    vbios_size = sizeof(vgabios_bin);
 
     priv->video_type = CSMWRAP_VIDEO_SEAVGABIOS;
 
@@ -522,8 +526,8 @@ EFI_STATUS csmwrap_video_fallback(struct csmwrap_priv *priv)
     cb_fb->reserved_mask_pos = 24;
     cb_fb->reserved_mask_size = 8;
 
-    /* Copy VGA BIOS to location */
-    memcpy((void*)VGABIOS_START, vgabios_bin, sizeof(vgabios_bin));
+    vbios_loc = vgabios_bin;
+    vbios_size = sizeof(vgabios_bin);
 
     priv->video_type = CSMWRAP_VIDEO_FALLBACK;