Re: [RFC PATCH 10/21] i386/xen: handle guest hypercalls

[Philippe Mathieu-Daudé]

On 5/12/22 18:31, David Woodhouse wrote:
> From: Joao Martins <joao.m.martins@oracle.com>
>
> This means handling the new exit reason for Xen but still
> crashing on purpose. As we implement each of the hypercalls
> we will then return the right return code.
>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> [dwmw2: Add CPL to hypercall tracing, disallow hypercalls from CPL > 0]
> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> ---
>   target/i386/kvm/kvm.c    |  5 +++++
>   target/i386/trace-events |  3 +++
>   target/i386/xen.c        | 45 ++++++++++++++++++++++++++++++++++++++++
>   target/i386/xen.h        |  1 +
>   4 files changed, 54 insertions(+)
>
> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
> index 4b21d03250..6396d11f1e 100644
> --- a/target/i386/kvm/kvm.c
> +++ b/target/i386/kvm/kvm.c
> @@ -5468,6 +5468,11 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run 
> *run)
>           assert(run->msr.reason == KVM_MSR_EXIT_REASON_FILTER);
>           ret = kvm_handle_wrmsr(cpu, run);
>           break;
> +#ifdef CONFIG_XEN

CONFIG_XEN is set when the _host_ has Xen development files available.

IIUC here you want to check if Xen HVM guest support is enabled.

You might want to use a different CONFIG_XEN_xxx key, which itself
depends on CONFIG_XEN.

> +    case KVM_EXIT_XEN:
> +        ret = kvm_xen_handle_exit(cpu, &run->xen);
> +        break;
> +#endif
>       default:
>           fprintf(stderr, "KVM: unknown exit reason %d\n", run->exit_reason);
>           ret = -1;


> diff --git a/target/i386/xen.h b/target/i386/xen.h
> index d4903ecfa1..3537415d31 100644
> --- a/target/i386/xen.h
> +++ b/target/i386/xen.h
> @@ -23,5 +23,6 @@
>   #define XEN_VERSION(maj, min) ((maj) << 16 | (min))
>   
>   int kvm_xen_init(KVMState *s, uint32_t xen_version);
> +int kvm_xen_handle_exit(X86CPU *cpu, struct kvm_xen_exit *exit);
>   
>   #endif /* QEMU_I386_XEN_H */