Hi Andrew,

On Tue, 21 Sep 2021, 00:41 Andrew Cooper, <andrew.cooper3@citrix.com> wrote:

> The mapping interface can only be used by x86 PV guests.
>

Tracebuffer works on Arm... The support was added a couple of years ago
using the foreign mapping interface.


> This can and should be fixed by changing to an acquire_resource() based
> interface, which is compatbile with x86 PVH and ARM dom0's, but until this
> happens, don't give the impression of this feature being useable elsewhere.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> ---
> CC: Jan Beulich <JBeulich@suse.com>
> CC: Roger Pau Monné <roger.pau@citrix.com>
> CC: Wei Liu <wl@xen.org>
> CC: Stefano Stabellini <sstabellini@kernel.org>
> CC: Julien Grall <julien@xen.org>
> CC: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
> ---
>  xen/common/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/xen/common/Kconfig b/xen/common/Kconfig
> index db687b1785e7..6b6f7139e6f0 100644
> --- a/xen/common/Kconfig
> +++ b/xen/common/Kconfig
> @@ -429,6 +429,7 @@ config DTB_FILE
>
>  config TRACEBUFFER
>         bool "Enable tracing infrastructure" if EXPERT
> +       depends on PV
>         default y
>         ---help---
>           Enable tracing infrastructure and pre-defined tracepoints within
> Xen.
> --
> 2.11.0
>
>