[Qemu-devel] [PATCH] Make -kernel for linux work with bochsbios

[Alexander Graf]

While trying to run -kernel with -bios pc-bios/pcbios.bin, I realized
that I was actually writing data to %es, but only set up %ds to a 32-bit
segment we want to write to.

So at the end of the day the data hasn't actually been copied. Oops.

So here's a fix to set ES instead of DS, which makes -kernel work with
BOCHS bios again (and actually makes the code do the correct thing)!

Signed-off-by: Alexander Graf <address@hidden>
---
 pc-bios/optionrom/linuxboot.S |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/pc-bios/optionrom/linuxboot.S b/pc-bios/optionrom/linuxboot.S
index 08c1ca6..ecd9cf2 100644
--- a/pc-bios/optionrom/linuxboot.S
+++ b/pc-bios/optionrom/linuxboot.S
@@ -102,11 +102,11 @@ copy_kernel:
        mov             $1, %eax
        mov             %eax, %cr0
 
-       /* So we can set DS to a 32-bit segment */
+       /* So we can set ES to a 32-bit segment */
        mov             $0x10, %eax
-       mov             %eax, %ds
+       mov             %eax, %es
 
-       /* We're now running in 16-bit CS, but 32-bit DS! */
+       /* We're now running in 16-bit CS, but 32-bit ES! */
 
        /* Load kernel and initrd */
        read_fw_blob(FW_CFG_KERNEL)
@@ -118,9 +118,9 @@ copy_kernel:
        mov             $0, %eax
        mov             %eax, %cr0
 
-       /* DS = CS */
+       /* ES = CS */
        mov             %cs, %ax
-       mov             %ax, %ds
+       mov             %ax, %es
 
        jmp             boot_kernel
 
-- 
1.6.0.2