All of lore.kernel.org
 help / color / mirror / Atom feed
From: Dario Faggioli <dfaggioli@suse.com>
To: Julien Grall <julien.grall@arm.com>,
	Mirela Simonovic <mirela.simonovic@aggios.com>
Cc: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Davorin Mista <dm@aggios.com>,
	Xen Devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH v3 10/10] xen/arm: Enable errata for secondary CPU on hotplug after the boot
Date: Fri, 11 May 2018 15:12:53 +0200	[thread overview]
Message-ID: <51bc496593c99d77909dd5193dd2c9c0c969667e.camel@suse.com> (raw)
In-Reply-To: <51febc3c-c55a-6512-1d32-0d2bb0a64df7@arm.com>


[-- Attachment #1.1: Type: text/plain, Size: 1456 bytes --]

On Fri, 2018-05-11 at 11:54 +0100, Julien Grall wrote:
> On 11/05/18 11:41, Mirela Simonovic wrote:
> "We should really avoid to use panic(...) if this is something the 
> system can survive. In that specific case, it would only affect the 
> current CPU. So it would be better to return an error and let the
> caller 
> decide what to do."
> 
> To summarize:
> 	1) Notifiers should only report an error and let the upper
> caller (here 
> notify_cpu_starting()) deciding what to do.
> 	2) I am OK with the BUG_ON in notify_cpu_starting() for now.
> 
And, in general, I agree with all this.

However (and I think I'm repeating this concept for, what, the 10th
time now?!?! :-P), in this specific case, the reason why none of the
existing CPU_STARTING callbacks report an error, is that the CPU
bringup process is, AFAICT, built around the assumption that once we
reached CPU_STARTING, things can't fail.

For this very reason, whatever new CPU_STARTING callback is introduced,
in this series or everywhere else, _can't_ fail, and _can't_ return any
error.

If we need to have a CPU_STARTING callback that can fail, we need to
change the CPU bringup process accordingly.

Regards,
Dario
-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Software Engineer @ SUSE https://www.suse.com/

[-- Attachment #1.2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

[-- Attachment #2: Type: text/plain, Size: 157 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

  parent reply	other threads:[~2018-05-11 13:12 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-27 17:12 [PATCH v3 00/10] xen/arm64: Suspend preconditions and CPU hotplug fixes Mirela Simonovic
2018-04-27 17:12 ` [PATCH v3 01/10] xen/arm64: Added handling of the trapped access to OSLSR register Mirela Simonovic
2018-04-27 17:12 ` [PATCH v3 02/10] xen/arm: Ignore write to GICD_ISACTIVERn registers (vgic-v2) Mirela Simonovic
2018-04-30 14:32   ` Julien Grall
2018-04-27 17:12 ` [PATCH v3 03/10] xen/arm: Implement CPU_OFF PSCI call (physical interface) Mirela Simonovic
2018-04-30 14:36   ` Julien Grall
2018-04-27 17:12 ` [PATCH v3 04/10] xen/arm: Remove __initdata and __init to enable CPU hotplug Mirela Simonovic
2018-04-27 17:12 ` [PATCH v3 05/10] xen/arm: Setup virtual paging for non-boot CPUs on hotplug/resume Mirela Simonovic
2018-04-30 14:47   ` Julien Grall
2018-05-07 14:55     ` Mirela Simonovic
2018-05-08 14:14       ` Julien Grall
2018-05-08 14:28         ` Mirela Simonovic
2018-05-09 10:32           ` Julien Grall
2018-04-27 17:12 ` [PATCH v3 06/10] xen/common: Restore IRQ affinity when hotplugging a pCPU Mirela Simonovic
2018-05-10  7:33   ` Dario Faggioli
2018-04-27 17:12 ` [PATCH v3 07/10] xen/arm: Release maintenance interrupt when CPU is hot-unplugged Mirela Simonovic
2018-04-30 14:51   ` Julien Grall
2018-04-27 17:12 ` [PATCH v3 08/10] xen/arm: Release timer interrupts " Mirela Simonovic
2018-04-30 15:58   ` Julien Grall
2018-05-07 15:33     ` Mirela Simonovic
2018-04-27 17:12 ` [PATCH v3 09/10] xen/arm: Free memory allocated for sibling/core maps on CPU hot-unplug Mirela Simonovic
2018-04-30 15:55   ` Julien Grall
2018-04-27 17:12 ` [PATCH v3 10/10] xen/arm: Enable errata for secondary CPU on hotplug after the boot Mirela Simonovic
2018-04-30 16:09   ` Julien Grall
2018-05-09 15:48     ` Mirela Simonovic
2018-05-09 16:32       ` Julien Grall
2018-05-10 11:57         ` Mirela Simonovic
2018-05-10 13:24           ` Mirela Simonovic
2018-05-10 13:29             ` Julien Grall
2018-05-10 14:12               ` Mirela Simonovic
2018-05-10 14:35                 ` Julien Grall
2018-05-10 14:25             ` Dario Faggioli
2018-05-10 15:00               ` Mirela Simonovic
2018-05-10 15:13                 ` Julien Grall
2018-05-10 15:49                   ` Mirela Simonovic
2018-05-10 16:02                     ` Julien Grall
2018-05-10 16:21                       ` Dario Faggioli
2018-05-10 16:24                     ` Dario Faggioli
2018-05-11 10:41                       ` Mirela Simonovic
2018-05-11 10:54                         ` Julien Grall
2018-05-11 12:07                           ` Mirela Simonovic
2018-05-11 12:20                             ` Mirela Simonovic
2018-05-11 13:08                               ` Julien Grall
2018-05-11 13:31                                 ` Dario Faggioli
     [not found]                                   ` <CAKPH-Nj2znmdcjZEfFf83WmrcBS_u4R33yPOxAPWw37RHVZ38g@mail.gmail.com>
2018-05-11 14:14                                     ` Dario Faggioli
2018-05-11 21:47                                   ` Stefano Stabellini
2018-05-14  9:44                                     ` Julien Grall
2018-05-14 16:59                                       ` Stefano Stabellini
2018-05-15 11:45                                         ` Mirela Simonovic
2018-05-11 13:12                           ` Dario Faggioli [this message]
2018-05-11 13:01                         ` Dario Faggioli
2018-05-10 16:12                   ` Dario Faggioli
2018-05-10 13:33           ` Dario Faggioli

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=51bc496593c99d77909dd5193dd2c9c0c969667e.camel@suse.com \
    --to=dfaggioli@suse.com \
    --cc=dm@aggios.com \
    --cc=edgar.iglesias@xilinx.com \
    --cc=julien.grall@arm.com \
    --cc=mirela.simonovic@aggios.com \
    --cc=sstabellini@kernel.org \
    --cc=xen-devel@lists.xen.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.