Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH v2 1/3] x86/xen: Avoid fast syscall path for Xen PV guests | From | Boris Ostrovsky <> | Date | Tue, 15 Dec 2015 10:21:37 -0500 |
| |
On 11/19/2015 04:55 PM, Boris Ostrovsky wrote: > After 32-bit syscall rewrite, and specifically after commit 5f310f739b4c > ("x86/entry/32: Re-implement SYSENTER using the new C path"), the stack > frame that is passed to xen_sysexit is no longer a "standard" one (i.e. > it's not pt_regs). > > Since we end up calling xen_iret from xen_sysexit we don't need to fix > up the stack and instead follow entry_SYSENTER_32's IRET path directly > to xen_iret. > > We can do the same thing for compat mode even though stack does not need > to be fixed. This will allow us to drop usergs_sysret32 paravirt op (in > the subsequent patch) > > Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> > Suggested-by: Andy Lutomirski <luto@amacapital.net>
I know this has been in the tip tree --- when do you think this will go Linus tree? In the 4.4 timeframe?
Xen 32-bit PV guests are broken without this.
Thanks. -boris
| ![\](/images/icornerr.gif) |