On Fri, Jan 27, 2012 at 04:02:30PM +0100, Kevin Wolf wrote: > Am 27.01.2012 15:17, schrieb Joerg Roedel: > > On Fri, Jan 27, 2012 at 02:55:12PM +0100, Kevin Wolf wrote: > >> Am 27.01.2012 14:34, schrieb Joerg Roedel: > >>> On Fri, Jan 27, 2012 at 01:58:38PM +0100, Kevin Wolf wrote: > >>>> Am 25.01.2012 17:00, schrieb Joerg Roedel: > >>> > >>>> I just retried. I use kvm-kmod and kvm.git with HEAD at ff92e9b5 plus > >>>> the tree patches of this series plus a printk to output exit_int_info in > >>>> task_switch_intercept(). I ran taskswitch2 from kvm-unittests and got > >>>> two failures and my VM86 unit test which hung when trying to return from > >>>> VM86. I also ran the kernel that made me aware of the issue initially. > >>>> All debug messages show exit_int_info = 0. > >>> > >>> Okay, you are testing on a K8 which has exactly this bug. As I just > >>> found out it is documented as erratum 701. The good news is that this > >>> only happens on K8 and Fam11h, any later AMD processor doesn't have this > >>> bug. > >> > >> Meh. Unless you give me a newer processor, this doesn't really help > >> me... Doesn't look like there's any way to get a workaround, is there? I > >> guess I'll have to hack it locally and possibly break other guests with > >> the hacked module. > > > > No, unfortunatly there is no workaround for this problem. How do you > > plan to hack around it? > > I know that my guest only uses iret and exceptions for task switches, so > I think in my case I can assume that any TASK_SWITCH_CALL is really a > TASK_SWITCH_GATE and I don't have to skip an instruction. > You still need to know what exception caused task switch. Some of them require you to skip an instruction. > Not quite upstreamable, obviously. > > Kevin -- Gleb. -- 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
