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

From: Julien Grall <julien@xen.org>
To: Oleksandr Tyshchenko <olekstysh@gmail.com>,
	xen-devel@lists.xenproject.org
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>,
	Paul Durrant <paul@xen.org>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH V6 23/24] xen/ioreq: Do not let bufioreq to be used on other than x86 arches
Date: Fri, 29 Jan 2021 10:21:34 +0000	[thread overview]
Message-ID: <344681d3-eb27-cb5b-2179-114b8e536c72@xen.org> (raw)
In-Reply-To: <1611884932-1851-24-git-send-email-olekstysh@gmail.com>

Hi Oleksandr,

On 29/01/2021 01:48, Oleksandr Tyshchenko wrote:
> From: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> 
> 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@epam.com>

Acked-by: Julien Grall <jgrall@amazon.com>

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