On Mon, 2009-11-23 at 17:13 +0000, Keir Fraser wrote: > On 23/11/2009 16:44, "Ian Campbell" <ian.campb...@citrix.com> wrote: > > >> But this is not just the return-to-user-space path you're changing, but > >> also the hypercall one. You certainly don't want an iret in that case. > > > > Don't the hypercalls already always go via iret? > > - testw $TRAP_syscall,4(%rsp) > > - jz iret_exit_to_guest > > IOW if TRAP_syscall is not set (i.e. this is a hypercall not a syscall) > > then exit via iret. > > I think not -- here TRAP_syscall means 'entered Xen via SYSCALL > instruction', not 'entered to do a syscall'. TRAP_syscall should be set > regardless of whether the SYSCALL instruction was executed by guest userland > or guest kernel.
Oh yes, I was confused into thinking it was the same as VGCF_in_syscall for some reason. Ian. > > -- Keir > > -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
