Hi Peter, On Thu, Nov 22, 2012 at 04:13:17PM +0000, Peter Maydell wrote: > On 22 November 2012 15:58, Will Deacon <will.deacon@xxxxxxx> wrote: > > +++ b/tools/kvm/arm/aarch32/smp-pen.S > > @@ -0,0 +1,30 @@ > > +#include "kvm/kvm-arch.h" > > + > > +#include "arm-common/gic.h" > > + > > + .arm > > + > > + .globl smp_pen_start > > + .globl smp_jump_addr > > + .globl smp_pen_end > > + > > + .align > > +smp_pen_start: > > + @ Ensure that the CPU interface is enabled for the wfi wakeup > > + ldr r0, =ARM_GIC_CPUI_BASE > > + mov r1, #GIC_CPUI_CTLR_EN > > + str r1, [r0] > > + > > + @ Now wait for the primary to poke us > > + adr r0, smp_jump_addr > > + dsb > > + wfi > > + ldr r1, [r0] > > + mov pc, r1 > > + > > + .ltorg > > + > > + .align > > +smp_jump_addr: > > + .long 0xdeadc0de > > +smp_pen_end: > > You've left the gate ajar on your pen -- this won't cope with > spurious WFI wakeups (the architecture allows WFI to return > at any time, down to the trivial case of "implemented as NOP"). > Needs a 'branch back to WFI if not yet poked' (or you could > make the initial value stored at smp_jump_addr be the address > of the wfi :-)) Thanks for pointing this out, somehow I missed it despite updating the ARMv8 code. Will fix for v3. Will -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
