Re: [PATCH v10 45/59] i386/xen: Implement HYPERVISOR_grant_table_op and GNTTABOP_[gs]et_verson

[Paul Durrant]

On 01/02/2023 14:31, David Woodhouse wrote:
> From: David Woodhouse <dwmw@amazon.co.uk>
>
> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> ---
>   hw/i386/kvm/xen_gnttab.c  | 31 ++++++++++++++++++++
>   hw/i386/kvm/xen_gnttab.h  |  5 ++++
>   target/i386/kvm/xen-emu.c | 60 +++++++++++++++++++++++++++++++++++++++
>   3 files changed, 96 insertions(+)
>
> diff --git a/hw/i386/kvm/xen_gnttab.c b/hw/i386/kvm/xen_gnttab.c
> index cd8c3ae60d..9dfce91f6a 100644
> --- a/hw/i386/kvm/xen_gnttab.c
> +++ b/hw/i386/kvm/xen_gnttab.c
> @@ -181,3 +181,34 @@ int xen_gnttab_map_page(uint64_t idx, uint64_t gfn)
>       return 0;
>   }
>   
> +int xen_gnttab_set_version_op(struct gnttab_set_version *set)
> +{
> +    int ret;
> +
> +    switch (set->version) {
> +    case 1:
> +        ret = 0;
> +        break;
> +
> +    case 2:
> +        /* Behave as before set_version was introduced. */
> +        ret = -ENOSYS;
> +        break;
> +
> +    default:
> +        ret = -EINVAL;
> +    }
> +
> +    set->version = 1;

Seems like an odd semantic. Only a version of 1 can result in a 
non-error exit. I suspect no harm will come from setting it in the error 
case though so...

Reviewed-by: Paul Durrant <paul@xen.org>