From: Greg Kurz <groug@kaod.org>
To: "Philippe Mathieu-Daudé" <philmd@redhat.com>
Cc: "Laurent Vivier" <lvivier@redhat.com>,
"Peter Maydell" <peter.maydell@linaro.org>,
"Thomas Huth" <thuth@redhat.com>,
"Eduardo Habkost" <ehabkost@redhat.com>,
"QEMU Developers" <qemu-devel@nongnu.org>,
qemu-ppc <qemu-ppc@nongnu.org>,
"Alex Bennée" <alex.bennee@linaro.org>,
"Thiago Jung Bauermann" <bauerman@linux.ibm.com>,
"David Gibson" <david@gibson.dropbear.id.au>
Subject: Re: [PATCH] cpu: Add starts_halted() method
Date: Thu, 9 Jul 2020 15:13:20 +0200 [thread overview]
Message-ID: <20200709151320.720fb0f0@bahia.lan> (raw)
In-Reply-To: <9951d4cb-7aba-bc65-91be-1fe57393d68e@redhat.com>
On Thu, 9 Jul 2020 14:21:04 +0200
Philippe Mathieu-Daudé <philmd@redhat.com> wrote:
> On 7/9/20 12:55 PM, Greg Kurz wrote:
> > On Thu, 9 Jul 2020 12:18:06 +0200
> > Philippe Mathieu-Daudé <philmd@redhat.com> wrote:
> >
[...]
> >>>
> >>> FYI, PAPR requires all vCPUs to be "stopped" by default. It is up to the
> >>> guest to start them explicitly through an RTAS call. The hypervisor is
> >>> only responsible to start a single vCPU (see spapr_cpu_set_entry_state()
> >>> called from spapr_machine_reset()) to be able to boot the guest.
> >>>
> >>> So I'm not sure to see how that would depend on the accelerator...
> >>
> >> $ qemu-system-ppc64 -M pseries-5.0,accel=tcg -d in_asm
> >> qemu-system-ppc64: warning: TCG doesn't support requested feature,
> >> cap-cfpc=workaround
> >> qemu-system-ppc64: warning: TCG doesn't support requested feature,
> >> cap-sbbc=workaround
> >> qemu-system-ppc64: warning: TCG doesn't support requested feature,
> >> cap-ibs=workaround
> >> qemu-system-ppc64: warning: TCG doesn't support requested feature,
> >> cap-ccf-assist=on
> >> ----------------
> >> IN:
> >> 0x00000100: 48003f00 b 0x4000
> >>
> >> ----------------
> >> IN:
> >> 0x00004000: 7c7f1b78 mr r31, r3
> >> 0x00004004: 7d6000a6 mfmsr r11
> >> 0x00004008: 3980a000 li r12, 0xa000
> >> 0x0000400c: 798c83c6 sldi r12, r12, 0x30
> >> 0x00004010: 7d6b6378 or r11, r11, r12
> >> 0x00004014: 7d600164 mtmsrd r11
> >> ...
> >>
> >> The vCPU doesn't seem stopped to me...
> >>
> >> Am I missing something?
> >>
> >
> > Yeah this is the boot vCPU which is required to be started
> > by the platform as explained above, but if you had more
> > vCPUs the other ones would be stopped until the guest OS
> > asks us to start them.
>
> Ah OK, so we are good :)
>
> The machine simply has to set the 'start-powered-off' flag on
> all vCPUS except the 1st one.
>
We only want the first vCPU to start when the platform is
fully configured, so I'd rather put 'start-powered-off' on
every body and explicitly power on the first one during
machine reset as we do now.
next prev parent reply other threads:[~2020-07-09 13:16 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 20:43 [PATCH] cpu: Add starts_halted() method Thiago Jung Bauermann
2020-07-07 21:49 ` Eduardo Habkost
2020-07-07 23:28 ` Thiago Jung Bauermann
2020-07-08 8:38 ` Philippe Mathieu-Daudé
2020-07-08 10:00 ` David Gibson
2020-07-08 13:14 ` Peter Maydell
2020-07-08 15:25 ` Eduardo Habkost
2020-07-08 15:32 ` Peter Maydell
2020-07-08 16:03 ` Eduardo Habkost
2020-07-08 17:09 ` Peter Maydell
2020-07-08 17:36 ` Eduardo Habkost
2020-07-08 20:11 ` Peter Maydell
2020-07-08 21:32 ` Eduardo Habkost
2020-07-09 3:05 ` Thiago Jung Bauermann
2020-07-09 3:26 ` Thiago Jung Bauermann
2020-07-09 10:24 ` Philippe Mathieu-Daudé
2020-07-10 20:02 ` Thiago Jung Bauermann
2020-07-10 20:17 ` Eduardo Habkost
[not found] ` <87k0zdm63s.fsf@linaro.org>
2020-07-10 20:16 ` Thiago Jung Bauermann
2020-07-11 17:55 ` Alex Bennée
2020-07-08 16:45 ` Philippe Mathieu-Daudé
2020-07-08 21:39 ` Eduardo Habkost
2020-07-09 5:11 ` Philippe Mathieu-Daudé
2020-07-09 9:54 ` Greg Kurz
2020-07-09 10:18 ` Philippe Mathieu-Daudé
2020-07-09 10:55 ` Greg Kurz
2020-07-09 12:21 ` Philippe Mathieu-Daudé
2020-07-09 13:13 ` Greg Kurz [this message]
2020-07-09 13:19 ` Philippe Mathieu-Daudé
2020-07-09 13:40 ` Peter Maydell
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=20200709151320.720fb0f0@bahia.lan \
--to=groug@kaod.org \
--cc=alex.bennee@linaro.org \
--cc=bauerman@linux.ibm.com \
--cc=david@gibson.dropbear.id.au \
--cc=ehabkost@redhat.com \
--cc=lvivier@redhat.com \
--cc=peter.maydell@linaro.org \
--cc=philmd@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=qemu-ppc@nongnu.org \
--cc=thuth@redhat.com \
/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.