Hypercalls from user-space

Hypercalls from user-space

[Srujan D. Kotikela]

Hi,

Can anyone tell me how to invoke hypercalls from user space? Or any
pointers for the same.

It's urgent, please help.

--
Srujan D. Kotikela

Re: Hypercalls from user-space

[Jeremy Fitzhardinge]

 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

Re: Hypercalls from user-space

[Ian Campbell]

On Fri, 2010-09-24 at 20:14 +0100, Jeremy Fitzhardinge 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.

And libxenctrl (see tools/libxc in the source) includes C wrappers for
many of them, as well as the necessary low level helpers to invoke the
ioctls etc.

Ian.

Re: Hypercalls from user-space

[Michal Novotny]

Hi Srujan,
I think you should have a look at libxc or libxl sources since this is 
accessing the hypercalls from user-space AFAIK.

Michal

On 09/24/2010 08:38 PM, 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.
>
> --
> Srujan D. Kotikela
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>    


-- 
Michal Novotny<minovotn@redhat.com>, RHCE
Virtualization Team (xen userspace), Red Hat

Re: Hypercalls from user-space

[Srujan D. Kotikela]

Hi All,

Thanks for the heads up.

--
Srujan D. Kotikela



On Mon, Sep 27, 2010 at 2:33 AM, Michal Novotny <minovotn@redhat.com> wrote:
> Hi Srujan,
> I think you should have a look at libxc or libxl sources since this is
> accessing the hypercalls from user-space AFAIK.
>
> Michal
>
> On 09/24/2010 08:38 PM, 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.
>>
>> --
>> Srujan D. Kotikela
>>
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@lists.xensource.com
>> http://lists.xensource.com/xen-devel
>>
>
>
> --
> Michal Novotny<minovotn@redhat.com>, RHCE
> Virtualization Team (xen userspace), Red Hat
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>

Re: Hypercalls from user-space

[Srujan D. Kotikela]

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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@goop.org>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
>

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[-- Attachment #2: Type: text/plain, Size: 138 bytes --]

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Re: Hypercalls from user-space

[Keir Fraser]

/proc/xen/privcmd should be available in domU as well. You might need to
enable some dom0 build config options to get it though.

 -- Keir

On 05/10/2010 22:31, "Srujan D. Kotikela" <ksrujandas@gmail.com> 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@goop.org> 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@lists.xensource.com
> http://lists.xensource.com/xen-devel

Re: Hypercalls from user-space

[Jeremy Fitzhardinge]

 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",

	J

>  -- Keir
>
> On 05/10/2010 22:31, "Srujan D. Kotikela" <ksrujandas@gmail.com> 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@goop.org> 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@lists.xensource.com
>> http://lists.xensource.com/xen-devel
>

Re: Hypercalls from user-space

[Keir Fraser]

On 05/10/2010 23:37, "Jeremy Fitzhardinge" <jeremy@goop.org> wrote:

>  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.

It ought to. Files like xsd_{kva,port} don't make sense for a domU, but
privcmd at least does as there's no reason a suitably privileged domU
userspace shouldn't be able to make hypercalls at the privilege level of the
domU.

 -- Keir

Re: Hypercalls from user-space

[Ian Campbell]

On Tue, 2010-10-05 at 23:37 +0100, Jeremy Fitzhardinge wrote:
> 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:

I see you fixed this properly in 66d850da but I think you also need the
following:


Subject: build privcmd for domU now that it is exposed

Fixes build error introduced in 66d850da "xen/privcmd: make privcmd
visible in domU"

drivers/built-in.o:(.data+0xd44): undefined reference to `privcmd_file_ops'
make[1]: *** [.tmp_vmlinux1] Error 1
make: *** [sub-make] Error 2

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

diff --git a/drivers/xen/xenfs/Makefile b/drivers/xen/xenfs/Makefile
index 4a0be9a..4fde944 100644
--- a/drivers/xen/xenfs/Makefile
+++ b/drivers/xen/xenfs/Makefile
@@ -1,4 +1,4 @@
 obj-$(CONFIG_XENFS) += xenfs.o
 
-xenfs-y			  = super.o xenbus.o
-xenfs-$(CONFIG_XEN_DOM0) += xenstored.o privcmd.o
+xenfs-y			  = super.o xenbus.o privcmd.o
+xenfs-$(CONFIG_XEN_DOM0) += xenstored.o

Re: Hypercalls from user-space

[Jeremy Fitzhardinge]

 On 10/13/2010 09:20 AM, Ian Campbell wrote:
> On Tue, 2010-10-05 at 23:37 +0100, Jeremy Fitzhardinge wrote:
>> 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:
> I see you fixed this properly in 66d850da but I think you also need the
> following:

Oops, thanks.

    J

>
> Subject: build privcmd for domU now that it is exposed
>
> Fixes build error introduced in 66d850da "xen/privcmd: make privcmd
> visible in domU"
>
> drivers/built-in.o:(.data+0xd44): undefined reference to `privcmd_file_ops'
> make[1]: *** [.tmp_vmlinux1] Error 1
> make: *** [sub-make] Error 2
>
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
>
> diff --git a/drivers/xen/xenfs/Makefile b/drivers/xen/xenfs/Makefile
> index 4a0be9a..4fde944 100644
> --- a/drivers/xen/xenfs/Makefile
> +++ b/drivers/xen/xenfs/Makefile
> @@ -1,4 +1,4 @@
>  obj-$(CONFIG_XENFS) += xenfs.o
>  
> -xenfs-y			  = super.o xenbus.o
> -xenfs-$(CONFIG_XEN_DOM0) += xenstored.o privcmd.o
> +xenfs-y			  = super.o xenbus.o privcmd.o
> +xenfs-$(CONFIG_XEN_DOM0) += xenstored.o
>
>