On Mon, Dec 07, 2015 at 03:58:11PM -0600, Andrew Jones wrote:
> On Mon, Dec 07, 2015 at 12:48:12PM +0300, Pavel Fedin wrote:
> > Hello!
> >
> > > FYI, I tried writing test cases for this issue with kvm-unit-tests. The
> > > issue didn't reproduce for me. It's quite possible my test cases are
> > > flawed
> >
> > Indeed they are, a very little thing fell through again... :)
> > It's not just SP, it's SP_EL0. And you never initialize it to anything
> > because your code always runs in kernel mode, so it's just
> > zero, so you get your zero.
> > But if you add a little thing in the beginning of your main():
> >
> > asm volatile("msr sp_el0, %0" : : "r" (0xDEADC0DE0BADC0DE));
>
> Ah! Thanks for this. The mmio test does now fail for me too. The sysreg
> test still doesn't fail for me (even though I'm doing the above on the
> vcpu I use for that too). Maybe there's something weird with which reg
> I'm using, and whether or not my attempt to get trapping enabled on it
> is working the way I expected. I'll play with it some more.
>
Must be the trapping thing. I switched to dbgbvr0_el1, which has
trapping enabled on it until it's touched, and was able the reproduce
the xzr issue it.
drew
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