On Sun, Jul 25, 2010 at 12:42:46PM -0400, Kevin O'Connor wrote:
On Sun, Jul 25, 2010 at 11:55:47AM +0300, Avi Kivity
What conditions are needed to trigger this path?
This can't occur
under normal operation, since it will fail badly with kvm on Intel.
It's called on every boot. I've personally only tested kvm on amd,
but I'd have to assume something must be allowing this to work on
BTW, the transition16big code does:
ljmpl $SEG32_MODE16BIG_CS, $(0xf0000 + 1f)
// Disable protected mode
movl %cr0, %eax
andl $~CR0_PE, %eax
movl %eax, %cr0
// far jump to flush CPU queue after transition to real mode
ljmpw $0xf000, $2f
Only the ljmpw is in big real mode with a code address >64K - the
"Disable protected mode" code is technically in 16bit protected mode.
I'm not sure if that helps explain why it works.