Re: [PATCH 2/4] x86/xen: use specific Xen pv interrupt entry for DF

[Jürgen Groß <jgross@xxxxxxxx>]

On 16.11.20 17:12, Andy Lutomirski wrote:
> On Mon, Nov 16, 2020 at 7:23 AM Juergen Gross <jgross@xxxxxxxx> wrote:
> > Xen PV guests don't use IST. For double fault interrupts switch to
> > the same model as NMI.
> >
> > Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> > ---
> >   arch/x86/include/asm/idtentry.h | 3 +++
> >   arch/x86/xen/enlighten_pv.c     | 8 +++++++-
> >   arch/x86/xen/xen-asm.S          | 2 +-
> >   3 files changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
> > index 3505c0396fa5..b35825392547 100644
> > --- a/arch/x86/include/asm/idtentry.h
> > +++ b/arch/x86/include/asm/idtentry.h
> > @@ -611,6 +611,9 @@ DECLARE_IDTENTRY_RAW(X86_TRAP_DB,   xenpv_exc_debug);
> >
> >   /* #DF */
> >   DECLARE_IDTENTRY_DF(X86_TRAP_DF,       exc_double_fault);
> > +#ifdef CONFIG_XEN_PV
> > +DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_DF,    xenpv_exc_double_fault);
> > +#endif
> >
> >   /* #VC */
> >   #ifdef CONFIG_AMD_MEM_ENCRYPT
> > diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
> > index 9f5e44c1f70a..803fbcb398c4 100644
> > --- a/arch/x86/xen/enlighten_pv.c
> > +++ b/arch/x86/xen/enlighten_pv.c
> > @@ -571,6 +571,12 @@ DEFINE_IDTENTRY_RAW(xenpv_exc_nmi)
> >          exc_nmi(regs);
> >   }
> >
> > +DEFINE_IDTENTRY_RAW_ERRORCODE(xenpv_exc_double_fault)
> > +{
> > +       /* On Xen PV, DF doesn't use IST.  The C part is the sane as native. */
> I would like to think that code is sane, but you probably meant "same".
Oh, this is the result of copy and paste. Now we have two sane
functions. :-)


Juergen

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