Re: [Xen-devel] [V0 PATCH] SVM: set/unset TF flag for single_step

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

----- mukesh.rathor@xxxxxxxxxx wrote:

> 
> Also strangely, when SVM VMEXIT_EXCEPTION_DB occurs, the TF flag is
> not cleared. This patch addresses that too.
..
>  
> diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
> index 76616ac..8addb94 100644
> --- a/xen/arch/x86/hvm/svm/svm.c
> +++ b/xen/arch/x86/hvm/svm/svm.c
> @@ -2350,6 +2350,8 @@ void svm_vmexit_handler(struct cpu_user_regs
> *regs)
>      case VMEXIT_EXCEPTION_DB:
>          if ( !v->domain->debugger_attached )
>              goto exit_and_crash;
> +        else
> +            regs->eflags &= ~X86_EFLAGS_TF;
>          domain_pause_for_debugger();
>          break;


I poked around debugger code and it looks to me that 
tools/debugger/gdbsx/xg:_change_TF() manages this flag.

-boris

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel