Re: [PATCH 6/8] KVM: xen: allow shared_info to be mapped by fixed HVA

From: David Woodhouse
Date: Thu Sep 14 2023 - 09:43:44 EST


On Thu, 2023-09-14 at 08:49 +0000, Paul Durrant wrote:
> @@ -1786,9 +1787,10 @@ struct kvm_xen_hvm_attr {
>                 __u8 long_mode;
>                 __u8 vector;
>                 __u8 runstate_update_flag;
> -               struct {
> +               union {
>                         __u64 gfn;
>  #define KVM_XEN_INVALID_GFN ((__u64)-1)
> +                       __u64 hva;
>                 } shared_info;
>                 struct {
>                         __u32 send_port;

Hm, do we consider that to be an acceptable ABI change? I suppose
arguably it's compatible with any existing source or binary code, and
that's the criterion that really matters?

Worth drawing attention to it in case anyone strongly objects.

Reviewed-by: David Woodhouse <dwmw@xxxxxxxxxxxx>

As discussed though, I'd be inclined not to *advertise* the new cap
yet; roll the auto-vcpu-info in with it and only set it in the final
patch where you add the test cases.

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