Re: [PATCH v7 27/51] i386/xen: Add support for Xen event channel delivery to vCPU

[Paul Durrant <xadimgnik@gmail.com>]

On 17/01/2023 12:31, David Woodhouse wrote:
> On Tue, 2023-01-17 at 11:11 +0000, Paul Durrant wrote:
>>
>> Ick. Do we really want cross-block gotos? For me it would look a lot
>> nicer if you did a forward jump here and later and put the label+code
>> after the `return 0`.
> 
> How's this?

 From my PoV, much better. Thanks.

> 
> static int set_vcpu_info(CPUState *cs, uint64_t gpa)
> {
>      X86CPU *cpu = X86_CPU(cs);
>      CPUX86State *env = &cpu->env;
>      MemoryRegionSection mrs = { .mr = NULL };
>      void *vcpu_info_hva = NULL;
>      int ret;
> 
>      ret = kvm_xen_set_vcpu_attr(cs, KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO, gpa);
>      if (ret || gpa == INVALID_GPA) {
>          goto out;
>      }
> 
>      mrs = memory_region_find(get_system_memory(), gpa, sizeof(struct vcpu_info));
>      if (!mrs.mr) {
>          ret = -EINVAL;
>      } else if (!mrs.mr->ram_block || mrs.size < sizeof(struct vcpu_info) ||
>                 !(vcpu_info_hva = qemu_map_ram_ptr(mrs.mr->ram_block,
>                                                    mrs.offset_within_region))) {
>          ret = -EINVAL;
>          memory_region_unref(mrs.mr);
>          mrs.mr = NULL;
>      }
> 
>   out:
>      if (env->xen_vcpu_info_mr) {
>          memory_region_unref(env->xen_vcpu_info_mr);
>      }
>      env->xen_vcpu_info_hva = vcpu_info_hva;
>      env->xen_vcpu_info_mr = mrs.mr;
>      return ret;
> }
> 
>