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| author | Rusty Russell <rusty@rustcorp.com.au> | 2007-10-22 05:03:36 +0400 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2007-10-23 09:49:54 +0400 |
| commit | 47436aa4ad054c1c7c8231618e86ebd9305308dc (patch) | |
| tree | a9ba6e0521f9116442144a86e781a3164ec86094 /drivers/lguest/x86 | |
| parent | c18acd73ffc209def08003a1927473096f66c5ad (diff) | |
| download | linux-47436aa4ad054c1c7c8231618e86ebd9305308dc.tar.xz | |
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>
Diffstat (limited to 'drivers/lguest/x86')
| -rw-r--r-- | drivers/lguest/x86/core.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c index a125109446dc..39f64c95de18 100644 --- a/drivers/lguest/x86/core.c +++ b/drivers/lguest/x86/core.c @@ -216,9 +216,10 @@ static int emulate_insn(struct lguest *lg) * guest_pa just subtracts the Guest's page_offset. */ unsigned long physaddr = guest_pa(lg, lg->regs->eip); - /* The guest_pa() function only works for Guest kernel addresses, but - * that's all we're trying to do anyway. */ - if (lg->regs->eip < lg->page_offset) + /* This must be the Guest kernel trying to do something, not userspace! + * The bottom two bits of the CS segment register are the privilege + * level. */ + if ((lg->regs->cs & 3) != GUEST_PL) return 0; /* Decoding x86 instructions is icky. */ |