On Mon, Mar 06, 2017 at 02:24:34PM +0000, Marc Zyngier wrote: > Let's define a new stub hypercall that resets the HYP configuration > to its default: hyp-stub vectors, and MMU disabled. > > Of course, for the hyp-stub itself, this is a trivial no-op. > Hypervisors will have a bit more work to do. > > Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> > --- > arch/arm64/include/asm/virt.h | 9 +++++++++ > arch/arm64/kernel/hyp-stub.S | 13 ++++++++++++- > 2 files changed, 21 insertions(+), 1 deletion(-) [...] > +ENTRY(__hyp_reset_vectors) > + str lr, [sp, #-16]! > + mov x0, #HVC_RESET_VECTORS > + hvc #0 > + ldr lr, [sp], #16 > + ret > +ENDPROC(__hyp_reset_vectors) Why do we need to specifically preserve lr across the hvc call? Is it corrupted by the EL2 code (if yes, are other caller-saved registers that need preserving)? I don't see something similar in the arch/arm code. -- Catalin
