On Thu, 7 Nov 2019 19:57:22 +0800
Guoheyi <guoh...@huawei.com> wrote:
> On 2019/11/7 16:57, Michael S. Tsirkin wrote:
> > 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 <guoh...@huawei.com> 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 <guoh...@huawei.com>
> >>>> Cc: Peter Maydell <peter.mayd...@linaro.org>
> >>>> Cc: "Michael S. Tsirkin" <m...@redhat.com>
> >>>> Cc: Cornelia Huck <coh...@redhat.com>
> >>>> Cc: Paolo Bonzini <pbonz...@redhat.com>
> >>>> Cc: Dave Martin <dave.mar...@arm.com>
> >>>> Cc: Marc Zyngier <marc.zyng...@arm.com>
> >>>> Cc: Mark Rutland <mark.rutl...@arm.com>
> >>>> Cc: James Morse <james.mo...@arm.com>
> >>>> ---
> >>>> 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.
> Do you mean to split this patch from the whole patch set and send it
> separately? Sorry I'm not clear about maintainers' work and may bring
> you some trouble...
My preferred approach:
- add a commit entitled "placeholder for headers update" that contains
the not-yet-upstream changes in the header files you need
- base the rest of your work on that
...
<review happens, series looks good>
...
- if kernel changes are upstream: replace the placeholder patch with a
real update (may include separate patches, if you need an additional
header); maintainer merges
- if kernel changes are not yet upstream: maintainer merges with
placeholder to a feature branch, replaces with real update and merges
once kernel patches hit upstream
(not every maintainer does the second approach; they may ask you
instead to resend with a proper headers update once the kernel changes
are upstream)
