Re: [RFC PATCH v2 21/22] i386/xen: implement HYPERVISOR_event_channel_op

[Paul Durrant]

On 09/12/2022 09:56, David Woodhouse wrote:
> From: Joao Martins <joao.m.martins@oracle.com>
>
> Additionally set XEN_INTERFACE_VERSION to most recent in order to
> exercise both event_channel_op and event_channel_op_compat.
>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> ---
>   target/i386/xen.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 45 insertions(+)
>
> diff --git a/target/i386/xen.c b/target/i386/xen.c
> index 1af336d9e5..f102c40f04 100644
> --- a/target/i386/xen.c
> +++ b/target/i386/xen.c
> @@ -18,11 +18,14 @@
>   #include "hw/i386/kvm/xen_overlay.h"
>   #include "hw/i386/kvm/xen_evtchn.h"
>   
> +#define __XEN_INTERFACE_VERSION__ 0x00040400
> +

Xen is actually at:

#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040e00

now.

>   #include "standard-headers/xen/version.h"
>   #include "standard-headers/xen/memory.h"
>   #include "standard-headers/xen/hvm/hvm_op.h"
>   #include "standard-headers/xen/hvm/params.h"
>   #include "standard-headers/xen/vcpu.h"
> +#include "standard-headers/xen/event_channel.h"
>   
>   static bool kvm_gva_to_gpa(CPUState *cs, uint64_t gva, uint64_t *gpa,
>                              size_t *len, bool is_write)
> @@ -452,6 +455,42 @@ static bool kvm_xen_hcall_vcpu_op(struct kvm_xen_exit 
> *exit, X86CPU *cpu,
>       return true;
>   }
>   
> +static bool kvm_xen_hcall_evtchn_op_compat(struct kvm_xen_exit *exit,
> +                                          X86CPU *cpu, uint64_t arg)
> +{
> +    struct evtchn_op op;
> +    int err = -EFAULT;
> +
> +    if (kvm_copy_from_gva(CPU(cpu), arg, &op, sizeof(op))) {
> +        goto err;
> +    }
> +
> +    switch (op.cmd) {
> +    default:
> +        return false;
> +    }
> +err:
> +    exit->u.hcall.result = err;
> +    return true;
> +}
> +
> +static bool kvm_xen_hcall_evtchn_op(struct kvm_xen_exit *exit,
> +                                    int cmd, uint64_t arg)
> +{
> +    int err = -ENOSYS;
> +
> +    switch (cmd) {
> +    case EVTCHNOP_init_control:
> +        err = -ENOSYS;

Why? It already has that value.

  Paul

> +        break;
> +    default:
> +        return false;
> +    }
> +
> +    exit->u.hcall.result = err;
> +    return true;
> +}
> +