Boot with virtual == physical to get closer to native Linux.

1) This allows us to get alot closer to booting bzImages.

2) It means we don't have to know page_offset.

3) The Guest needs to modify the boot pagetables to create the
   PAGE_OFFSET mapping before jumping to C code.

4) guest_pa() walks the page tables rather than using page_offset.

5) We don't use page_offset to figure out whether to emulate: it was
   always kinda quesationable, and won't work for instructions done
   before remapping (bzImage unpacking in particular).

6) We still want the kernel address for tlb flushing: have the initial
   hypercall give us that, too.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 2 insertions, 5 deletions

diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index 3a06b51c98ad..090f30cbf24c 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -86,6 +86,7 @@ struct lguest_data lguest_data = {
         .hcall_status = { [0 ... LHCALL_RING_SIZE-1] = 0xFF },
         .noirq_start = (u32)lguest_noirq_start,
         .noirq_end = (u32)lguest_noirq_end,
+        .kernel_address = PAGE_OFFSET,
         .blocked_interrupts = { 1 }, /* Block timer interrupts */
         .syscall_vec = SYSCALL_VECTOR,
 };
@@ -1033,11 +1034,7 @@ __init void lguest_init(void *boot)
 
         /*G:070 Now we've seen all the paravirt_ops, we return to
          * lguest_init() where the rest of the fairly chaotic boot setup
-         * occurs.
-         *
-         * The Host expects our first hypercall to tell it where our "struct
-         * lguest_data" is, so we do that first. */
-        hcall(LHCALL_LGUEST_INIT, __pa(&lguest_data), 0, 0);
+         * occurs. */
 
         /* The native boot code sets up initial page tables immediately after
          * the kernel itself, and sets init_pg_tables_end so they're not