Re: [PATCH V6 23/24] xen/ioreq: Do not let bufioreq to be used on other than x86 arches

[Julien Grall <julien@xxxxxxx>]

Hi Oleksandr,

On 29/01/2021 01:48, Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
>
> This patch prevents the device model running on other than x86
> systems to use buffered I/O feature for now.
>
> Please note, there is no caller which requires to send buffered
> I/O request on Arm currently and the purpose of this check is
> to catch any future user of bufioreq.
>
> Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

Cheers,

> ---
> Please note, this is a split/cleanup/hardening of Julien's PoC:
> "Add support for Guest IO forwarding to a device emulator"
>
> Changes V5 -> V6:
>     - new patch
> ---
> ---
>   xen/common/ioreq.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/xen/common/ioreq.c b/xen/common/ioreq.c
> index 67ef1f7..a36137d 100644
> --- a/xen/common/ioreq.c
> +++ b/xen/common/ioreq.c
> @@ -629,6 +629,9 @@ static int ioreq_server_create(struct domain *d, int 
> bufioreq_handling,
>       unsigned int i;
>       int rc;
>   
> +    if ( !IS_ENABLED(CONFIG_X86) && bufioreq_handling )
> +        return -EINVAL;
> +
>       if ( bufioreq_handling > HVM_IOREQSRV_BUFIOREQ_ATOMIC )
>           return -EINVAL;
>   
--
Julien Grall