[xen staging] xen/ioreq: Do not let bufioreq to be used on other than x86 arches

[patchbot@xxxxxxx]

commit 2fbd7e609e1803ac5e5c26e22aa8e4b5a6cddbb1
Author:     Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
AuthorDate: Fri Jan 29 03:48:51 2021 +0200
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Fri Jan 29 16:56:09 2021 +0000

    xen/ioreq: Do not let bufioreq to be used on other than x86 arches
    
    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: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Julien Grall <jgrall@xxxxxxxxxx>
    Acked-by: Paul Durrant <paul@xxxxxxx>
---
 xen/common/ioreq.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/xen/common/ioreq.c b/xen/common/ioreq.c
index 67ef1f706e..a36137d41d 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;
 
--
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