At 14:53 +0100 on 17 Aug (1439823232), Ben Catterall wrote: > On 12/08/15 14:33, Andrew Cooper wrote: > > On 12/08/15 14:29, Andrew Cooper wrote: > >> On 11/08/15 19:29, Boris Ostrovsky wrote: > >>> Would switching TR only when we know that we need to enter this > >>> deprivileged mode help? > >> This is an absolute must. It is not safe to use syscall/sysexit without > >> IST in place for NMIs and MCEs. > >> > >>> Assuming that it is less expensive than copying the stack. > >> I was referring to the stack overflow issue, and whether it might be > >> sensible to pro-actively which TR. > > > > Ahem! s/which/switch/ > > > > ~Andrew > > > > So, have we arrived at a decision for this? Thanks!
Seems to have stalled a bit. OK, I propose that: - we use TR/IST to make Xen take interrupts/exceptions at a different SP; - we make that SP be an extension of the main stack, so that things like current() Just Work[tm]; - we set this up and tear it down when we enter/leave depriv mode. - someone ought to look at the case where IST handlers copy themselves to the main stack, and see if we need to adjust that too. Any other proposals? I think we can leave the question of TR switching on VMEXIT as a separate issue. Cheers, Tim. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
