[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] xen/x86: Adjust stack pointer in xen_sysexit
On Nov 17, 2015 6:40 AM, "Boris Ostrovsky" <boris.ostrovsky@xxxxxxxxxx> wrote: > > On 11/16/2015 04:55 PM, H. Peter Anvin wrote: >> >> On 11/16/15 12:22, Borislav Petkov wrote: >>> >>> Huh, so what's wrong with a jump: >>> >>> jmp 1f >>> swapgs >>> 1: >>> >> What is the point of that jump? >> >>>> If it would make you feel better, it could be X86_BUG_XENPV :-p >>> >>> That doesn't matter - I just don't want to open the flood gates on >>> pseudo feature bits. >>> >>> hpa, what do you think? >> >> Pseudo feature bits are fine, we already have plenty of them. They make >> sense as they let us reuse a lot of infrastructure. > > > > So how about something like this? And then I think we can remove > usergs_sysret32 and irq_enable_sysexit pv ops completely as noone will use > them (lguest doesn't set them) > Looks good to me. Does Xen have any sysexit/sysret32 equivalent to return to 32-bit user mode? If so, it could be worth trying to wire it up by patching the jz instead of the test instruction. Also, I'd prefer X86_FEATURE_XENPV. IMO "PV" means too many things to too many people. --Andy _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |