Re: [RFC PATCH 14/21] i386/xen: implement HYPERVISOR_vcpu_op

[Philippe Mathieu-Daudé]

On 5/12/22 18:31, David Woodhouse wrote:
> From: Joao Martins <joao.m.martins@oracle.com>
>
> This is simply when guest tries to register a vcpu_info
> and since vcpu_info placement is optional in the minimum ABI
> therefore we can just fail with -ENOSYS
>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> ---
>   target/i386/xen.c | 19 +++++++++++++++++++
>   1 file changed, 19 insertions(+)

> +static int kvm_xen_hcall_vcpu_op(struct kvm_xen_exit *exit,
> +                                 int cmd, uint64_t arg)
> +{
> +    switch (cmd) {
> +    case VCPUOP_register_vcpu_info: {
> +            /* no vcpu info placement for now */
> +            exit->u.hcall.result = -ENOSYS;
> +            return 0;
> +        }
> +    }

Can we log some trace-event or GUEST_ERROR?

> +    exit->u.hcall.result = -ENOSYS;
> +    return HCALL_ERR;
> +}