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Re: [Xen-devel] Hypercalls from user-space

To: Keir Fraser <keir@xxxxxxx>
Subject: Re: [Xen-devel] Hypercalls from user-space
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Date: Tue, 05 Oct 2010 15:37:53 -0700
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx, "Srujan D. Kotikela" <ksrujandas@xxxxxxxxx>
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 On 10/05/2010 03:09 PM, Keir Fraser wrote:
> /proc/xen/privcmd should be available in domU as well. You might need to
> enable some dom0 build config options to get it though.

xenfs doesn't init privcmd on non-privileged kernels.

Srujan, this should be enough to enable it in domU:

diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
index 229c831..6495c61 100644
--- a/drivers/xen/xenfs/super.c
+++ b/drivers/xen/xenfs/super.c
@@ -109,7 +109,7 @@ static int xenfs_fill_super(struct super_block *sb, void 
*data, int silent)
        if (rc < 0)
                return rc;
-       if (xen_initial_domain()) {
+       if (1 || xen_initial_domain()) {
                xenfs_create_file(sb, sb->s_root, "xsd_kva",
                                  &xsd_kva_file_ops, NULL, S_IRUSR|S_IWUSR);
                xenfs_create_file(sb, sb->s_root, "xsd_port",


>  -- Keir
> On 05/10/2010 22:31, "Srujan D. Kotikela" <ksrujandas@xxxxxxxxx> wrote:
>> Hi Jeremy,
>> I am able to do hypercalls in privileged domain. i want to invoke hypercalls
>> (to send EVENT notifications) from DomU.
>> Amy pointers for the same would be appreciated.
>> --
>> Srujan D. Kotikela
>> On Fri, Sep 24, 2010 at 2:14 PM, Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:
>>>  On 09/24/2010 11:38 AM, Srujan D. Kotikela wrote:
>>>> Hi,
>>>> Can anyone tell me how to invoke hypercalls from user space? Or any
>>>> pointers for the same.
>>>> It's urgent, please help.
>>> You can't directly invoke hypercalls from userspace.   In a privileged
>>> domain you can use ioctls on /proc/xen/privcmd.
>>>     J
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>> http://lists.xensource.com/xen-devel

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