Re: [PATCH] x86/domctl: don't ignore errors from vmce_restore_vcpu()

[Andrew Cooper <andrew.cooper3@citrix.com>]

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On 29/01/14 15:57, Jan Beulich wrote:
> What started out as a simple cleanup patch (eliminating the redundant
> check of domctl->cmd before setting "copyback", which as a result
> turned the "ext_vcpucontext_out" label useless) revealed a bug in the
> handling of XEN_DOMCTL_set_ext_vcpucontext.
>
> Fix this, retaining the cleanup, and at once dropping a stale comment
> and an accompanying formatting issue.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

>
> --- a/xen/arch/x86/domctl.c
> +++ b/xen/arch/x86/domctl.c
> @@ -815,7 +815,7 @@ long arch_do_domctl(
>          ret = -ESRCH;
>          if ( (evc->vcpu >= d->max_vcpus) ||
>               ((v = d->vcpu[evc->vcpu]) == NULL) )
> -            goto ext_vcpucontext_out;
> +            break;
>  
>          if ( domctl->cmd == XEN_DOMCTL_get_ext_vcpucontext )
>          {
> @@ -847,17 +847,20 @@ long arch_do_domctl(
>              evc->vmce.caps = v->arch.vmce.mcg_cap;
>              evc->vmce.mci_ctl2_bank0 = v->arch.vmce.bank[0].mci_ctl2;
>              evc->vmce.mci_ctl2_bank1 = v->arch.vmce.bank[1].mci_ctl2;
> +
> +            ret = 0;
> +            copyback = 1;
>          }
>          else
>          {
>              ret = -EINVAL;
>              if ( evc->size < offsetof(typeof(*evc), vmce) )
> -                goto ext_vcpucontext_out;
> +                break;
>              if ( is_pv_domain(d) )
>              {
>                  if ( !is_canonical_address(evc->sysenter_callback_eip) ||
>                       !is_canonical_address(evc->syscall32_callback_eip) )
> -                    goto ext_vcpucontext_out;
> +                    break;
>                  fixup_guest_code_selector(d, evc->sysenter_callback_cs);
>                  v->arch.pv_vcpu.sysenter_callback_cs      =
>                      evc->sysenter_callback_cs;
> @@ -873,13 +876,11 @@ long arch_do_domctl(
>                  v->arch.pv_vcpu.syscall32_disables_events =
>                      evc->syscall32_disables_events;
>              }
> -            else
> -            /* We do not support syscall/syscall32/sysenter on 32-bit Xen. */
> -            if ( (evc->sysenter_callback_cs & ~3) ||
> -                 evc->sysenter_callback_eip ||
> -                 (evc->syscall32_callback_cs & ~3) ||
> -                 evc->syscall32_callback_eip )
> -                goto ext_vcpucontext_out;
> +            else if ( (evc->sysenter_callback_cs & ~3) ||
> +                      evc->sysenter_callback_eip ||
> +                      (evc->syscall32_callback_cs & ~3) ||
> +                      evc->syscall32_callback_eip )
> +                break;
>  
>              BUILD_BUG_ON(offsetof(struct xen_domctl_ext_vcpucontext,
>                                    mcg_cap) !=
> @@ -896,13 +897,9 @@ long arch_do_domctl(
>  
>                  ret = vmce_restore_vcpu(v, &vmce);
>              }
> +            else
> +                ret = 0;
>          }
> -
> -        ret = 0;
> -
> -    ext_vcpucontext_out:
> -        if ( domctl->cmd == XEN_DOMCTL_get_ext_vcpucontext )
> -            copyback = 1;
>      }
>      break;
>  
>
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel


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