From: Greg KH <gregkh@linuxfoundation.org>
To: Niels Dettenbach <nd@syndicat.com>
Cc: linux-arch@vger.kernel.org, stable@vger.kernel.org, trivial@kernel.org
Subject: Re: [PATCH 1/1] x86: SMT broken on Xen PV DomU since 6.9 (updated)
Date: Thu, 12 Sep 2024 07:21:55 +0200 [thread overview]
Message-ID: <2024091258-quickness-clapping-7418@gregkh> (raw)
In-Reply-To: <3301863.oiGErgHkdL@gongov>
On Wed, Sep 11, 2024 at 05:49:46PM +0200, Niels Dettenbach wrote:
> Am Mittwoch, 11. September 2024, 10:53:30 schrieb Niels Dettenbach:
> > virtual machines under Xen Hypervisor (DomU) running in Xen PV mode use a
> > special, nonstandard synthetized CPU topology which "just works" under
> > kernels 6.9.x while newer kernels assuming a "crash kernel" and disable
> > SMT (reducing to one CPU core) because the newer topology implementation
> > produces a wrong error "[Firmware Bug]: APIC enumeration order not
> > specification compliant" after new topology checks which are improper for
> > Xen PV platform. As a result, the kernel disables SMT and activates just
> > one CPU core within the VM (DomU).
> >
> > The patch disables the regarding checks if it is running in Xen PV
> > mode (only) and bring back SMT / all CPUs as in the past to such DomU
> > VMs.
> >
> > Signed-off-by: Niels Dettenbach <nd@syndicat.com>
> >
>
> Signed-off-by: Niels Dettenbach <nd@syndicat.com>
> ---
>
> A reworked proposal patch which substitutes my initial proposed patch:
>
>
> --- linux/arch/x86/kernel/cpu/topology.c 2024-09-11 17:42:42.699278317 +0200
> +++ linux/arch/x86/kernel/cpu/topology.c.orig 2024-09-11 09:53:16.194095250 +0200
<snip>
Please submit this to the proper developers and maintainers for this
code, as the get_maintainers script will tell you as the documentation
states. As it is, this isn't going anywhere as you did not include them
properly.
good luck!
greg k-h
prev parent reply other threads:[~2024-09-12 5:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-11 8:53 [PATCH 1/1] x86: SMT broken on Xen PV DomU since 6.9 Niels Dettenbach
2024-09-11 15:49 ` [PATCH 1/1] x86: SMT broken on Xen PV DomU since 6.9 (updated) Niels Dettenbach
2024-09-12 5:21 ` Greg KH [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=2024091258-quickness-clapping-7418@gregkh \
--to=gregkh@linuxfoundation.org \
--cc=linux-arch@vger.kernel.org \
--cc=nd@syndicat.com \
--cc=stable@vger.kernel.org \
--cc=trivial@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.