On Fri, Nov 09, 2018 at 12:56:54PM +0000, Peter Maydell wrote: > On 9 November 2018 at 12:49, Mark Rutland <mark.rutland@xxxxxxx> wrote: > > I'm not saying anything about *decisions*. I'm saying that we can make > > the state consistent by advancing the singlestep state in the same way > > that HW does, at the instant it advances the PC. > > > > i.e. do that in kvm_skip_instr(), as I've done in my local tree. > > > > That mirrors the HW, and we don't need to special-case any handling for > > emulated vs non-emulated instructions. > > You also need to do it in the "set PC because we're making the guest > take an exception" code path, which doesn't go through kvm_skip_instr(). Sure. > This corresponds to the two kinds of "step completed" in hardware as > noted in DDI0487D.a D2.12.3 fig D2-3 footnote b: > * executing the instruction to be stepped without taking an exception > * taking an exception to an exception level that debug exceptions > are enabled from [ie guest EL1 in our case] Thanks for the pointer! Mark.
