Re: [Xen-devel] Lenovo X200 IOMMU support through Xen 4.6 iommu=no-igfx switch

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Sun, Jun 26, 2016 at 11:48:44PM +0000, Thierry Laurion wrote:
> Sorry for the precedent post that was written a bit too fast. Libreboot was
> flashed when I wrote it, which is the equivalent of a having vt-d
> deactivated (iommu=0). Thanks to a user that read this post and wrote to me
> personally so I could do my mea culpa. Sorry for the precedent misleading
> post.
> 
> Xen on a GM45 chipset and with IGD i915 driver is still getting the system
> hanged when vt-d is activated. I'm willing to borrow a machine to the Xen
> developer that could fix the iommu=no-igfx code for gm45 chipset to
> actually work.

This sounds like http://wiki.xenproject.org/wiki/Paravirtualized_DRM
issues.

Can you try and also attach lspci -v ?


diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index aef87fd..cf31aad 100644
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -35,7 +35,7 @@
 #ifdef CONFIG_INTEL_IOMMU
 #define USE_PCI_DMA_API 1
 #else
-#define USE_PCI_DMA_API 0
+#define USE_PCI_DMA_API 1
 #endif
 
 struct intel_gtt_driver {
@@ -654,6 +654,7 @@ static int intel_gtt_init(void)
 
        intel_private.needs_dmar = USE_PCI_DMA_API && INTEL_GTT_GEN > 2;
 
+       printk("%s: %s DMA ops\n", __func__,intel_private.needs_dmar ? "Using" 
: "Not using");
        ret = intel_gtt_setup_scratch_page();
        if (ret != 0) {
                intel_gtt_cleanup();
> 
> A ticket is opened here with current states of thing:
> https://github.com/QubesOS/qubes-issues/issues/1594#issuecomment-209213917
> 
> Sorry about that (and repost since I wrote the same misleading post to two
> places)
> Thierry
> 
> Le dim. 28 févr. 2016 à 14:03, Thierry Laurion <thierry.laurion@xxxxxxxxx>
> a écrit :
> 
> > The problem wasn't with xen iommu support but kms/drm and i915 driver.
> >
> > Passing to the kernel i915.preliminary_hw_support=1 fixes it all :)
> >
> > Thanks
> >
> > Le mer. 6 janv. 2016 à 22:11, Thierry Laurion <thierry.laurion@xxxxxxxxx>
> > a écrit :
> >
> >> Nope. That commit is present in 4.6 and results in x200 being able to
> >> boot xen.
> >>
> >> Not having that option makes xen hang at boot.
> >>
> >> If present, it works until other vm access pass-through devices, which
> >> I'm not able to troubleshoot even through amt SOL.
> >>
> >> See here for debug logs:
> >> https://groups.google.com/forum/m/#!topic/qubes-users/bHQHjXqinaU
> >>
> >> Le mer. 6 janv. 2016 09:35, Jan Beulich <JBeulich@xxxxxxxx> a écrit :
> >>
> >>> >>> On 22.12.15 at 19:04, <thierry.laurion@xxxxxxxxx> wrote:
> >>> > iommu=no-igfx is a gamechanger for Qubes support through 3.1 RC1
> >>> release,
> >>> > thanks to Xen 4.6 :)
> >>> >
> >>> > The Lenovo X200 supports vt-x, vt-d and TPM as reported and required by
> >>> > Qubes in the HCL attached to this e-mail. The problem is that when
> >>> Qubes
> >>> > launches it's netvm which uses IOMMU to talk to it's network card, it
> >>> > freezes the whole system up. Even when specifying sync_console, I
> >>> don't get
> >>> > much more verbosity. I ordered a PCMCIA to serial adapter which will be
> >>> > shipped to my door late January... Meanwhile, booting with iommu=0
> >>> makes
> >>> > things work, but a potential hardware component being compromised has
> >>> > chances to compromise the whole system since compartmentalization is
> >>> not
> >>> > guaranteed without IOMMU (vt-d).
> >>> >
> >>> > A little more love is needed from xen to make that laptop line
> >>> supported by
> >>> > Qubes and a nice alternative to the costy Librem currently promoted by
> >>> > Qubes-Purism
> >>> > partnership
> >>>
> >>> Is all of the above and below a quite complicated way of expressing
> >>> that you'd like to see commit 146341187a backported to 4.6.x?
> >>>
> >>> Jan
> >>>
> >>> > <
> >>> http://arstechnica.com/gadgets/2015/12/qubes-os-will-ship-pre-installed-on-p
> >>> > urisms-security-focused-librem-13-laptop/>which
> >>> > suggest that the laptop will be Respect Your Freedom compliant in the
> >>> > future with Intel participation in removing ME and AMT
> >>> > <http://libreboot.org/faq/#intelme>, which is not guaranteed at all.
> >>> > <
> >>> http://www.phoronix.com/scan.php?page=news_item&px=Purism-Librem-Still-Blobbe
> >>> > d>
> >>> > If Xen 4.6 can cooperate with Penryn GM45 chipset, it's all MiniFree
> >>> laptops
> >>> > <http://minifree.org/product-category/laptops/> (and Libreboot
> >>> support of
> >>> > those <http://libreboot.org/docs/hcl/x200.html>) that will be
> >>> potential
> >>> > candidates!
> >>> > Please share the love so that the community has a cheap alternative.
> >>> >
> >>> > Requirements to replicate bug:
> >>> > Model: X200 745434U with p8700 CPU running 1067a microcode(important),
> >>> > upgrable to 8go
> >>> > BIOS: Lenovo 3.22/1.07 (latest from 2013
> >>> > <http://support.lenovo.com/ca/en/downloads/ds015007>)
> >>> > Network card supports FLReset+ as requested here
> >>> > <http://wiki.xen.org/wiki/VTd_HowTo>.
> >>> > Bios settings: vt-d and vt-x needs to be enforced.
> >>> > Xen command line option required
> >>> > <http://www.gossamer-threads.com/lists/xen/devel/393647> to boot:
> >>> > iommu=no-igfx
> >>> >
> >>> > Here is the current debug trace/status on Qubes side of things
> >>> > <https://groups.google.com/forum/#!topic/qubes-users/bHQHjXqinaU>.
> >>> > If you have any hint, please contribute :)
> >>> >
> >>> > Help me say happy new years to all security conscious people out there
> >>> :)
> >>> >
> >>> > Merry Christmas all,
> >>> > Thierry Laurion
> >>> >
> >>> >
> >>> >
> >>> >
> >>> >
> >>> > --
> >>> > Thierry Laurion
> >>>
> >>>
> >>>
> >>>

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