Re: [Xen-devel] [V5 PATCH 1/1] x86/xen: Set EFER.NX and EFER.SCE in PVH guests

From: Mukesh Rathor
Date: Fri Sep 12 2014 - 16:47:13 EST


On Fri, 12 Sep 2014 16:42:58 -0400
Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote:

> On Wed, Sep 10, 2014 at 04:36:06PM -0700, Mukesh Rathor wrote:
> > This fixes two bugs in PVH guests:
> >
> > - Not setting EFER.NX means the NX bit in page table entries is
> > ignored on Intel processors and causes reserved bit page faults
> > on AMD processors.
> >
> > - After the Xen commit 7645640d6ff1 ("x86/PVH: don't set EFER_SCE
> > for pvh guest") PVH guests are required to set EFER.SCE to enable
> > the SYSCALL instruction.
> >
> > Secondary VCPUs are started with pagetables with the NX bit set so
> > EFER.NX must be set before using any stack or data segment.
> > xen_pvh_cpu_early_init() is the new secondary VCPU entry point that
> > sets EFER before jumping to cpu_bringup_and_idle().
> >
> > Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
> > Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
>
> Huh? So who wrote it? Or did you mean 'Reviewed-by'?

No, meant SOB. I wrote v1, v2, then David came up with V3 and v4,
then i took comments from v4 and came up with v5.

-Mukesh

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/