Re: [Xen-devel] [PATCH 2/2] trace: trace hypercalls inside a multicall

[Frediano Ziglio <frediano.ziglio@xxxxxxxxxx>]

On Thu, 2012-05-24 at 11:37 +0100, David Vrabel wrote:
> From: David Vrabel <david.vrabel@xxxxxxxxxx>
> 
> Add a trace record for every hypercall inside a multicall.
> 
> Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
> ---
>  xen/common/multicall.c |   29 +++++++++++++++++++++++++++++
>  1 files changed, 29 insertions(+), 0 deletions(-)
> 
> diff --git a/xen/common/multicall.c b/xen/common/multicall.c
> index 6c1a9d7..1da53bb 100644
> --- a/xen/common/multicall.c
> +++ b/xen/common/multicall.c
> @@ -11,6 +11,7 @@
>  #include <xen/multicall.h>
>  #include <xen/guest_access.h>
>  #include <xen/perfc.h>
> +#include <xen/trace.h>
>  #include <asm/current.h>
>  #include <asm/hardirq.h>
>  
> @@ -19,6 +20,32 @@ typedef long ret_t;
>  #define xlat_multicall_entry(mcs)
>  #endif
>  
> +#ifdef COMPAT
> +static void __trace_multicall_call(multicall_entry_t *call)
> +{
> +    unsigned long args[5];
> +    int i;
> +
> +    for (i = 0; i < ARRAY_SIZE(args); i++)
> +        args[i] = call->args[i];
> +
> +    __trace_hypercall(call->op, args);
> +}
> +#else
> +static void __trace_multicall_call(multicall_entry_t *call)
> +{
> +    __trace_hypercall(call->op, call->args);
> +}
> +#endif
> +
> +static void trace_multicall_call(multicall_entry_t *call)
> +{
> +    if ( !tb_init_done )
> +        return;
> +
> +    __trace_multicall_call(call);
> +}
> +
>  ret_t
>  do_multicall(
>      XEN_GUEST_HANDLE(multicall_entry_t) call_list, unsigned int nr_calls)
> @@ -47,6 +74,8 @@ do_multicall(
>              break;
>          }
>  
> +        trace_multicall_call(&mcs->call);
> +
>          do_multicall_call(&mcs->call);
>  
>  #ifndef NDEBUG

Good, I'd personally add a way (subclass perhaps) to exclude such traces
as could be very performance consuming.

I'd also add something like sub op (shadow_op or domctl operations have
sub operations which could be useful to understand).

Frediano

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