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
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