Re: [PATCH] x86 vm_event: reset monitor in vm_event_cleanup_domain()

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

On 27/01/2016 19:42, Razvan Cojocaru wrote:
> It is currently possible to leave a monitor flag enabled even
> after vm_event_cleanup_domain() has been called, potentially
> leading to a crash in hvm_msr_write_intercept() and hvm_set_crX()
> (when v->arch.vm_event has become NULL, but the corresponding
> corresponding v->domain->arch.monitor flag is non-zero).
> This patch zeroes out arch.monitor in vm_event_cleanup_domain().
>
> Signed-off-by: Razvan Cojocaru <rcojocaru@bitdefender.com>

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

> ---
>  xen/arch/x86/vm_event.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/xen/arch/x86/vm_event.c b/xen/arch/x86/vm_event.c
> index 9677ecc..08d678a 100644
> --- a/xen/arch/x86/vm_event.c
> +++ b/xen/arch/x86/vm_event.c
> @@ -56,6 +56,7 @@ void vm_event_cleanup_domain(struct domain *d)
>      }
>  
>      d->arch.mem_access_emulate_each_rep = 0;
> +    memset(&d->arch.monitor, 0, sizeof(d->arch.monitor));
>  }
>  
>  void vm_event_toggle_singlestep(struct domain *d, struct vcpu *v)