Re: [RFC v2 11/14] linux-headers/kvm.h: add capability to forward hypercall

[Michael S. Tsirkin]

On Thu, Nov 07, 2019 at 09:44:36AM +0800, Guoheyi wrote:
> 
> 
> On 2019/11/7 1:55, Cornelia Huck wrote:
> > On Tue, 5 Nov 2019 17:10:53 +0800
> > Heyi Guo <address@hidden> wrote:
> > 
> > > To keep backward compatibility, we add new KVM capability
> > > "KVM_CAP_FORWARD_HYPERCALL" to probe whether KVM supports forwarding
> > > hypercall to userspace.
> > > 
> > > The capability should be enabled explicitly, for we don't want user
> > > space application to deal with unexpected hypercall exits. After
> > > enabling this cap, all HVC calls unhandled by kvm will be forwarded to
> > > user space.
> > > 
> > > Signed-off-by: Heyi Guo <address@hidden>
> > > Cc: Peter Maydell <address@hidden>
> > > Cc: "Michael S. Tsirkin" <address@hidden>
> > > Cc: Cornelia Huck <address@hidden>
> > > Cc: Paolo Bonzini <address@hidden>
> > > Cc: Dave Martin <address@hidden>
> > > Cc: Marc Zyngier <address@hidden>
> > > Cc: Mark Rutland <address@hidden>
> > > Cc: James Morse <address@hidden>
> > > ---
> > >   linux-headers/linux/kvm.h |  1 +
> > >   target/arm/sdei.c         | 16 ++++++++++++++++
> > >   target/arm/sdei.h         |  2 ++
> > >   3 files changed, 19 insertions(+)
> > > 
> > > diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
> > > index 3d9b18f7f8..36c9b3859f 100644
> > > --- a/linux-headers/linux/kvm.h
> > > +++ b/linux-headers/linux/kvm.h
> > > @@ -1000,6 +1000,7 @@ struct kvm_ppc_resize_hpt {
> > >   #define KVM_CAP_PMU_EVENT_FILTER 173
> > >   #define KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 174
> > >   #define KVM_CAP_HYPERV_DIRECT_TLBFLUSH 175
> > > +#define KVM_CAP_FORWARD_HYPERCALL 176
> > >   #ifdef KVM_CAP_IRQ_ROUTING
> > Is this cap upstream already? I would have thought your header sync
> > would have brought it in, then. (Saying this, that header sync looks
> > awfully small.)
> > 
> > If it is not upstream yet, please split off this hunk into a separate
> > patch -- it's a bit annoying, but makes life easier for merging.
> No, it is not upstream yet. The whole framework and interfaces between KVM
> and qemu are still under discussion. I'll keep in mind of this when moving
> forward to next steps...
> 
> Thanks,
> HG

It's best to add it in some other place meanwhile.
Then we can drop it when it's in an upstream header.


> > 
> > 
> > .
> > 
>