From: Ross Lagerwall <ross.lagerwall@citrix.com>
To: Paul Durrant <Paul.Durrant@citrix.com>,
Ian Jackson <Ian.Jackson@citrix.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Cc: Anthony Perard <anthony.perard@citrix.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Stefano Stabellini <sstabellini@kernel.org>,
Juergen Gross <jgross@suse.com>
Subject: Re: [Qemu-devel] [Xen-devel] [PATCH v2 0/*] xen: xen-domid-restrict improvements
Date: Tue, 10 Oct 2017 14:40:20 +0100 [thread overview]
Message-ID: <74e38d45-c173-4df1-c696-ca19cda41287@citrix.com> (raw)
In-Reply-To: <56626155ee594136b8fe0d0de03ca4f5@AMSPEX02CL03.citrite.net>
On 10/06/2017 02:19 PM, Paul Durrant wrote:
>> -----Original Message-----
>> From: Xen-devel [mailto:xen-devel-bounces@lists.xen.org] On Behalf Of
>> Ross Lagerwall
>> Sent: 06 October 2017 13:58
>> To: Ian Jackson <Ian.Jackson@citrix.com>; qemu-devel@nongnu.org
>> Cc: Anthony Perard <anthony.perard@citrix.com>; xen-
>> devel@lists.xenproject.org; Stefano Stabellini <sstabellini@kernel.org>;
>> Juergen Gross <jgross@suse.com>
>> Subject: Re: [Xen-devel] [PATCH v2 0/*] xen: xen-domid-restrict
>> improvements
>>
>> On 10/04/2017 05:18 PM, Ian Jackson wrote:
>>> (Resending this because 1. I got the CC for xen-devel wrong; 2. I got
>>> the subject wrong: there are actually 8 patches; 3. I mangled
>>> Anthony's name in theheaders. Sorry for the noise.)
>>>
>>> I have been working on trying to get qemu, when running as a Xen
>>> device model, to _actually_ not have power equivalent to root.
>>>
>>> I think I have achieved this, with some limitations (which will be
>>> discussed in my series against xen.git.
>>>
>>> However, there are changes to qemu needed. In particular
>>>
>>> * The -xen-domid-restrict option does not work properly right now.
>>> It only restricts a small subset of the descriptors qemu has open.
>>> I am introducing a new library call in the Xen libraries for this,
>>> xentoolcore_restrict_all.
>>>
>>
>> Hi Ian,
>>
>> I'm testing your QEMU and Xen patch series and found that after being
>> restricted, QEMU fails to setup up the VGA memory properly which causes
>> a complete stall with stdvga. With cirrus it mostly works although it
>> seems to have reduced performance.
>>
>> I think it happens when the VM sets up the BAR some time after
>> xen_restrict() has been called. The failure comes from QEMU calling
>> xc_domain_add_to_physmap() which calls do_memory_op() and finally
>> xencall2(). But the underlying xencall fd has been replaced with /dev/null.
>
> Oh, that's a PITA. This is because of the slightly hacky way that the VRAM is dealt with (it needing to be moved into the BAR of the PCI VGA device at the point where guest firmware programs it). Maybe we need a new dm_op for this?
>
If no one objects, I propose adding the following calls to
libxendevicemodel (with underlying Xen implementations, of course) that
would be usable after the xendevicemodel handle has been restricted.
xendevicemodel_add_to_physmap(xendevicemodel_handle *dmod,
domid_t domid,
unsigned long idx,
xen_pfn_t gpfn);
This is equivalent to xc_domain_add_to_physmap() with
space==XENMAPSPACE_gmfn.
xendevicemodel_pin_memory_cacheattr(xendevicemodel_handle *dmod,
domid_t domid,
uint64_t start,
uint64_t end,
uint32_t type);
This is equivalent to xc_domain_pin_memory_cacheattr().
--
Ross Lagerwall
WARNING: multiple messages have this Message-ID (diff)
From: Ross Lagerwall <ross.lagerwall@citrix.com>
To: Paul Durrant <Paul.Durrant@citrix.com>,
Ian Jackson <Ian.Jackson@citrix.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Cc: Anthony Perard <anthony.perard@citrix.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
Stefano Stabellini <sstabellini@kernel.org>,
Juergen Gross <jgross@suse.com>
Subject: Re: [PATCH v2 0/*] xen: xen-domid-restrict improvements
Date: Tue, 10 Oct 2017 14:40:20 +0100 [thread overview]
Message-ID: <74e38d45-c173-4df1-c696-ca19cda41287@citrix.com> (raw)
In-Reply-To: <56626155ee594136b8fe0d0de03ca4f5@AMSPEX02CL03.citrite.net>
On 10/06/2017 02:19 PM, Paul Durrant wrote:
>> -----Original Message-----
>> From: Xen-devel [mailto:xen-devel-bounces@lists.xen.org] On Behalf Of
>> Ross Lagerwall
>> Sent: 06 October 2017 13:58
>> To: Ian Jackson <Ian.Jackson@citrix.com>; qemu-devel@nongnu.org
>> Cc: Anthony Perard <anthony.perard@citrix.com>; xen-
>> devel@lists.xenproject.org; Stefano Stabellini <sstabellini@kernel.org>;
>> Juergen Gross <jgross@suse.com>
>> Subject: Re: [Xen-devel] [PATCH v2 0/*] xen: xen-domid-restrict
>> improvements
>>
>> On 10/04/2017 05:18 PM, Ian Jackson wrote:
>>> (Resending this because 1. I got the CC for xen-devel wrong; 2. I got
>>> the subject wrong: there are actually 8 patches; 3. I mangled
>>> Anthony's name in theheaders. Sorry for the noise.)
>>>
>>> I have been working on trying to get qemu, when running as a Xen
>>> device model, to _actually_ not have power equivalent to root.
>>>
>>> I think I have achieved this, with some limitations (which will be
>>> discussed in my series against xen.git.
>>>
>>> However, there are changes to qemu needed. In particular
>>>
>>> * The -xen-domid-restrict option does not work properly right now.
>>> It only restricts a small subset of the descriptors qemu has open.
>>> I am introducing a new library call in the Xen libraries for this,
>>> xentoolcore_restrict_all.
>>>
>>
>> Hi Ian,
>>
>> I'm testing your QEMU and Xen patch series and found that after being
>> restricted, QEMU fails to setup up the VGA memory properly which causes
>> a complete stall with stdvga. With cirrus it mostly works although it
>> seems to have reduced performance.
>>
>> I think it happens when the VM sets up the BAR some time after
>> xen_restrict() has been called. The failure comes from QEMU calling
>> xc_domain_add_to_physmap() which calls do_memory_op() and finally
>> xencall2(). But the underlying xencall fd has been replaced with /dev/null.
>
> Oh, that's a PITA. This is because of the slightly hacky way that the VRAM is dealt with (it needing to be moved into the BAR of the PCI VGA device at the point where guest firmware programs it). Maybe we need a new dm_op for this?
>
If no one objects, I propose adding the following calls to
libxendevicemodel (with underlying Xen implementations, of course) that
would be usable after the xendevicemodel handle has been restricted.
xendevicemodel_add_to_physmap(xendevicemodel_handle *dmod,
domid_t domid,
unsigned long idx,
xen_pfn_t gpfn);
This is equivalent to xc_domain_add_to_physmap() with
space==XENMAPSPACE_gmfn.
xendevicemodel_pin_memory_cacheattr(xendevicemodel_handle *dmod,
domid_t domid,
uint64_t start,
uint64_t end,
uint32_t type);
This is equivalent to xc_domain_pin_memory_cacheattr().
--
Ross Lagerwall
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
next prev parent reply other threads:[~2017-10-10 21:23 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-04 16:18 [Qemu-devel] [PATCH v2 0/*] xen: xen-domid-restrict improvements Ian Jackson
2017-10-04 16:18 ` Ian Jackson
2017-10-04 16:18 ` [Qemu-devel] [PATCH 1/8] xen: link against xentoolcore Ian Jackson
2017-10-04 16:18 ` Ian Jackson
2017-10-04 16:18 ` [Qemu-devel] [PATCH 2/8] xen: restrict: use xentoolcore_restrict_all Ian Jackson
2017-10-04 16:18 ` Ian Jackson
2017-10-04 16:18 ` [Qemu-devel] [PATCH 3/8] xen: defer call to xen_restrict until after os_setup_post Ian Jackson
2017-10-04 16:18 ` Ian Jackson
2017-10-09 15:50 ` [Qemu-devel] " Anthony PERARD
2017-10-09 15:50 ` Anthony PERARD
2017-10-09 16:58 ` [Qemu-devel] " Ian Jackson
2017-10-09 16:58 ` Ian Jackson
2017-10-10 11:40 ` [Qemu-devel] " Anthony PERARD
2017-10-10 11:40 ` Anthony PERARD
2017-10-10 17:16 ` [Qemu-devel] " Ian Jackson
2017-10-10 17:16 ` Ian Jackson
2017-10-09 17:00 ` Ian Jackson
2017-10-04 16:18 ` [Qemu-devel] [PATCH 4/8] xen: destroy_hvm_domain: Move reason into a variable Ian Jackson
2017-10-04 16:18 ` Ian Jackson
2017-10-04 16:18 ` [Qemu-devel] [PATCH 5/8] xen: move xc_interface compatibility fallback further up the file Ian Jackson
2017-10-04 16:18 ` Ian Jackson
2017-10-04 16:18 ` [Qemu-devel] [PATCH 6/8] xen: destroy_hvm_domain: Try xendevicemodel_shutdown Ian Jackson
2017-10-04 16:18 ` Ian Jackson
2017-10-04 16:18 ` [Qemu-devel] [PATCH 7/8] os-posix: Provide new -runasid option Ian Jackson
2017-10-04 16:18 ` Ian Jackson
2017-10-06 12:47 ` [Qemu-devel] " Ross Lagerwall
2017-10-06 12:47 ` Ross Lagerwall
2017-10-06 14:24 ` [Qemu-devel] " Ian Jackson
2017-10-06 14:24 ` Ian Jackson
2017-10-06 14:39 ` Ian Jackson
2017-10-06 12:59 ` [Qemu-devel] " Peter Maydell
2017-10-06 12:59 ` Peter Maydell
2017-10-06 14:24 ` Ian Jackson
2017-10-06 14:24 ` Ian Jackson
2017-10-06 14:39 ` Ian Jackson
2017-10-09 5:46 ` Markus Armbruster
2017-10-09 5:46 ` Markus Armbruster
2017-10-09 15:05 ` Ian Jackson
2017-10-09 15:05 ` Ian Jackson
2017-10-09 15:24 ` Daniel P. Berrange
2017-10-09 15:24 ` Daniel P. Berrange
2017-10-09 16:52 ` Ian Jackson
2017-10-09 16:52 ` Ian Jackson
2017-10-09 16:59 ` Ian Jackson
2017-10-10 7:43 ` Markus Armbruster
2017-10-10 7:43 ` Markus Armbruster
2017-10-10 17:11 ` Ian Jackson
2017-10-10 17:11 ` Ian Jackson
2017-10-11 9:52 ` Ian Jackson
2017-10-09 15:14 ` Ian Jackson
2017-10-04 16:18 ` [Qemu-devel] [PATCH 8/8] RFC configure: do_compiler: Dump some extra info under bash Ian Jackson
2017-10-04 16:18 ` Ian Jackson
2017-10-06 12:58 ` [Qemu-devel] [PATCH v2 0/*] xen: xen-domid-restrict improvements Ross Lagerwall
2017-10-06 12:58 ` Ross Lagerwall
2017-10-06 13:19 ` [Qemu-devel] [Xen-devel] " Paul Durrant
2017-10-06 13:19 ` Paul Durrant
2017-10-10 13:40 ` Ross Lagerwall [this message]
2017-10-10 13:40 ` Ross Lagerwall
2017-10-10 17:21 ` [Qemu-devel] [Xen-devel] " Ian Jackson
2017-10-10 17:21 ` Ian Jackson
2017-10-06 14:17 ` [Qemu-devel] " Ian Jackson
2017-10-06 14:17 ` Ian Jackson
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