On Mon, Apr 6, 2015 at 11:30 AM, Boris Ostrovsky
On 04/06/2015 01:44 PM, Andrew Cooper wrote:At the risk of redundancy, did you test on Intel hardware? At least
On 06/04/2015 16:29, Andy Lutomirski wrote:
On Mon, Apr 6, 2015 at 7:10 AM, Konrad Rzeszutek Wilk64bit PV kernels must bounce through Xen to switch from the kernel to
On Fri, Apr 03, 2015 at 03:52:30PM -0700, Andy Lutomirski wrote:sysexit never tasted very good :-p
[cc: Boris and Konrad. Whoops]Is there an commit (or name of patch) that explains why
On Fri, Apr 3, 2015 at 3:51 PM, Andy Lutomirski <luto@xxxxxxxxxx>
We don't use irq_enable_sysexit on 64-bit kernels any more. Remove
kernels is unsavory?
We're (hopefully) not breaking 32-bit-user-space-on-64-bit, but we're
trying an unconventional approach to making the code faster and less
scary. As a result, 64-bit kernels won't use sysexit any more.
Hopefully Xen is okay with the slightly sneaky thing we're doing.
AFAICT Xen thinks of sysretl and sysexit as slightly funny irets, so I
don't expect there to be any problem.
the user pagetables (since both kernel and userspace are both actually
running in ring3 with user pages).
As a result, exit to userspace ends up as a hypercall into Xen which has
an effect very similar to an `iret`, but with some extra fixup in the
I can't forsee any Xen issues as a result of this patch.
I ran tip plus this patch (plus another patch that fixes an unrelated Xen
regression in tip) through our test suite and it completed without problems.
I also ran some very simple 32-bit programs in a 64-bit PV guest and didn't
see any problems there neither.
on native systems, the code in question never executes on AMD systems.