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

[Pierre Morel]

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 ?


> @@ -0,0 +1,22 @@
> +/*
> + * s390 zPCI KVM interfaces
> + *
> + * Copyright 2022 IBM Corp.
> + * Author(s): Matthew Rosato <mjrosato@linux.ibm.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or (at
> + * your option) any later version. See the COPYING file in the top-level
> + * directory.
> + */
> +
> +#include "qemu/osdep.h"
> +
> +#include "kvm/kvm_s390x.h"
> +#include "hw/s390x/pv.h"
> +#include "hw/s390x/s390-pci-kvm.h"
> +#include "cpu_models.h"
> +
> +bool s390_pci_kvm_interp_allowed(void)
> +{
> +    return kvm_s390_get_zpci_op() && !s390_is_pv();
> +}


--
Pierre Morel
IBM Lab Boeblingen