Pkg xen devel - Sep 2022 - Bug#1020787: Bug#1020787: linux-image-5.19.0-2-amd64: After updating to 5.19 kernel the VMs are started without XSAVE CPU flags

Hi Marek,

On dinsdag 27 september 2022 02:16:31 CEST Marek Marczykowski-G?recki
wrote:
> On Tue, Sep 27, 2022 at 01:39:46AM +0200, Diederik de Haas wrote:
> > In kernel 5.19 the following commits were added under
> > ``arch/x86/kernel/fpu/``:
> > 
> > b91c0922bf1ed15b67a6faa404bc64e3ed532ec2 x86/fpu: Cleanup variable
> > shadowing 
> > 8ad7e8f696951f192c6629a0cbda9ac94c773159 x86/fpu/xsave: Support
> > XSAVEC in the kernel 
> > f5c0b4f30416c670408a77be94703d04d22b57df x86/prctl:
> > Remove pointless task argument
8ad7e8f696951f192c6629a0cbda9ac94c773159 seems to be the 'offending'
commit ...
> > Also found this patch which should make the error msg more informative
...
> > https://lore.kernel.org/all/20220810221909.12768-1-andrew.cooper3 at
citrix.c
> > om/ Even though I haven't experienced it (yet?), the language of
this
> > patch seems to indicate you're not alone with it.
> 
> There is also Xen patch fixing the issue:
> https://lore.kernel.org/xen-devel/a4ec41e6-16cd-4452-19c1-5d6d9e3bddf8 at
suse.
> com/
http://xenbits.xen.org/gitweb/?
p=xen.git;a=commit;h=c3bd0b83ea5b7c0da6542687436042eeea1e7909 is where it's 
committed in Xen's master branch. I haven't seen a backport to 4.16
(yet?)

Looking at the patch thread you linked, I get the impression that the change 
in the Linux kernel exposed the problem on the Xen side, but the Linux kernel 
change didn't introduce a bug (Andrew's patch seems to make it more 
informative, not correct a bug).

But I'm not sure that assesment is correct. What's your take on this?

Cheers,
  Diederik
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 228 bytes
Desc: This is a digitally signed message part.
URL:
<http://alioth-lists.debian.net/pipermail/pkg-xen-devel/attachments/20220927/ff2c170c/attachment.sig>

On Tue, Sep 27, 2022 at 01:59:42PM +0200, Diederik de Haas
wrote:
> http://xenbits.xen.org/gitweb/?
> p=xen.git;a=commit;h=c3bd0b83ea5b7c0da6542687436042eeea1e7909 is where
it's
> committed in Xen's master branch. I haven't seen a backport to 4.16
(yet?)
> 
> Looking at the patch thread you linked, I get the impression that the
change
> in the Linux kernel exposed the problem on the Xen side, but the Linux
kernel
> change didn't introduce a bug (Andrew's patch seems to make it more
> informative, not correct a bug).
> 
> But I'm not sure that assesment is correct. What's your take on
this?
Yes, that seems correct.

-- 
Best Regards,
Marek Marczykowski-G?recki
Invisible Things Lab
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: not available
URL:
<http://alioth-lists.debian.net/pipermail/pkg-xen-devel/attachments/20220927/c8af64c9/attachment.sig>

Hi,

On Tue, Sep 27, 2022 at 01:59:42PM +0200, Diederik de Haas
wrote:
> http://xenbits.xen.org/gitweb/?
> p=xen.git;a=commit;h=c3bd0b83ea5b7c0da6542687436042eeea1e7909 is where
it's
> committed in Xen's master branch. I haven't seen a backport to 4.16
(yet?)
Does this mean that all versions of hypervisor need this patch
backported in order to support Linux kernel 5.19+ as dom0 or domU?

Cheers,
Andy

On Tue, Sep 27, 2022 at 12:08:58PM +0000, Andy Smith
wrote:
> Hi,
> 
> On Tue, Sep 27, 2022 at 01:59:42PM +0200, Diederik de Haas wrote:
> > http://xenbits.xen.org/gitweb/?
> > p=xen.git;a=commit;h=c3bd0b83ea5b7c0da6542687436042eeea1e7909 is where
it's
> > committed in Xen's master branch. I haven't seen a backport to
4.16 (yet?)
> 
> Does this mean that all versions of hypervisor need this patch
> backported in order to support Linux kernel 5.19+ as dom0 or domU?
Yes, I think so. I've seen the issue on Xen 4.14 too.

-- 
Best Regards,
Marek Marczykowski-G?recki
Invisible Things Lab
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: not available
URL:
<http://alioth-lists.debian.net/pipermail/pkg-xen-devel/attachments/20220927/ca918308/attachment.sig>