Re: [PATCH v7 3/8] s390x/pci: enable for load/store intepretation

[Matthew Rosato]

On 6/22/22 4:35 AM, Pierre Morel wrote:
> On 6/6/22 22:36, Matthew Rosato wrote:
> > If the ZPCI_OP ioctl reports that is is available and usable, then the
> > underlying KVM host will enable load/store intepretation for any guest
> > device without a SHM bit in the guest function handle.  For a device that
> > will be using interpretation support, ensure the guest function handle
> > matches the host function handle; this value is re-checked every time the
> > guest issues a SET PCI FN to enable the guest device as it is the only
> > opportunity to reflect function handle changes.
> >
> > By default, unless interpret=off is specified, interpretation support 
> > will
> > always be assumed and exploited if the necessary ioctl and features are
> > available on the host kernel.  When these are unavailable, we will 
> > silently
> > revert to the interception model; this allows existing guest 
> > configurations
> > to work unmodified on hosts with and without zPCI interpretation support,
> > allowing QEMU to choose the best support model available.
> >
> > Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
> > ---
> >   hw/s390x/meson.build            |  1 +
> >   hw/s390x/s390-pci-bus.c         | 66 ++++++++++++++++++++++++++++++++-
> >   hw/s390x/s390-pci-inst.c        | 16 ++++++++
> >   hw/s390x/s390-pci-kvm.c         | 22 +++++++++++
> >   include/hw/s390x/s390-pci-bus.h |  1 +
> >   include/hw/s390x/s390-pci-kvm.h | 24 ++++++++++++
> >   target/s390x/kvm/kvm.c          |  7 ++++
> >   target/s390x/kvm/kvm_s390x.h    |  1 +
> >   8 files changed, 137 insertions(+), 1 deletion(-)
> >   create mode 100644 hw/s390x/s390-pci-kvm.c
> >   create mode 100644 include/hw/s390x/s390-pci-kvm.h
> >
> > diff --git a/hw/s390x/meson.build b/hw/s390x/meson.build
> > index feefe0717e..f291016fee 100644
> > --- a/hw/s390x/meson.build
> > +++ b/hw/s390x/meson.build
> > @@ -23,6 +23,7 @@ s390x_ss.add(when: 'CONFIG_KVM', if_true: files(
> >     's390-skeys-kvm.c',
> >     's390-stattrib-kvm.c',
> >     'pv.c',
> > +  's390-pci-kvm.c',
> >   ))
>
> Here...
>
> > diff --git a/hw/s390x/s390-pci-kvm.c b/hw/s390x/s390-pci-kvm.c
> > new file mode 100644
> > index 0000000000..0f16104a74
> > --- /dev/null
> > +++ b/hw/s390x/s390-pci-kvm.c
>
> ...and here:
>
> Shouldn't this file go in target/s390x/kvm ?

I wasn't sure tbh, there seems to be precedent to use hw/s390x already 
today for kvm-specific pieces of hardware support (e.g. tod, skeys, pv, 
stattrib) whereas target/s390x/kvm has only kvm.c?

Anyone else have an opinion on this one?