From: David Gibson <david@gibson.dropbear.id.au>
To: "Cédric Le Goater" <clg@kaod.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
qemu-ppc@nongnu.org, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 06/13] spapr/xive: fix migration of the XiveTCTX under TCG
Date: Tue, 12 Feb 2019 11:22:24 +1100 [thread overview]
Message-ID: <20190212002223.GD1884@umbus.fritz.box> (raw)
In-Reply-To: <36cd0056-a8b6-7128-5bf4-d5a479d99d76@kaod.org>
[-- Attachment #1: Type: text/plain, Size: 1583 bytes --]
On Fri, Feb 08, 2019 at 08:12:12AM +0100, Cédric Le Goater wrote:
> On 2/8/19 6:36 AM, David Gibson wrote:
> > On Mon, Jan 07, 2019 at 07:39:39PM +0100, Cédric Le Goater wrote:
> >> When the thread interrupt management state is retrieved from the KVM
> >> VCPU, word2 is saved under the QEMU XIVE thread context to print out
> >> the OS CAM line under the QEMU monitor.
> >>
> >> This breaks the migration of a TCG guest (and with KVM when
> >> kernel_irqchip=off) because the matching algorithm of the presenter
> >> relies on the OS CAM value. Fix with an extra reset of the thread
> >> contexts to restore the expected value.
> >>
> >> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> >
> > Why is the CAM value you get from KVM different from the one you
> > expect in qemu?
>
> An NVT base identifier is allocated for each VM at the OPAL level
> and each vCPU getd an increment of this value. It is pushed in the
> OS CAM line when the vCPU is scheduled to run.
>
> KVM XIVE names this identifier a VP id.
>
> The QEMU emulation of XIVE uses a fixed value for the NVT base
> identifier.
Ah, I see.
Hmm. Really this highlights why I'm uneasy migrating the whole TCTX
as just a blob of registers, even though only some of them are really
runtime state, and others are machine configuration that can be worked
out separately at the two ends.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
next prev parent reply other threads:[~2019-02-12 1:53 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-07 18:39 [Qemu-devel] [PATCH 00/13] spapr: add KVM support to the XIVE interrupt mode Cédric Le Goater
2019-01-07 18:39 ` [Qemu-devel] [PATCH 01/13] linux-headers: update to 5.0 Cédric Le Goater
2019-01-07 18:39 ` [Qemu-devel] [PATCH 02/13] spapr/xive: add KVM support Cédric Le Goater
2019-02-06 2:39 ` David Gibson
2019-01-07 18:39 ` [Qemu-devel] [PATCH 03/13] spapr/xive: add state synchronization with KVM Cédric Le Goater
2019-02-06 2:42 ` David Gibson
2019-01-07 18:39 ` [Qemu-devel] [PATCH 04/13] spapr/xive: introduce a VM state change handler Cédric Le Goater
2019-02-06 2:49 ` David Gibson
2019-01-07 18:39 ` [Qemu-devel] [PATCH 05/13] spapr/xive: add migration support for KVM Cédric Le Goater
2019-02-07 3:41 ` David Gibson
2019-01-07 18:39 ` [Qemu-devel] [PATCH 06/13] spapr/xive: fix migration of the XiveTCTX under TCG Cédric Le Goater
2019-02-08 5:36 ` David Gibson
2019-02-08 7:12 ` Cédric Le Goater
2019-02-12 0:22 ` David Gibson [this message]
2019-02-12 6:58 ` Cédric Le Goater
2019-01-07 18:39 ` [Qemu-devel] [PATCH 07/13] ppc/xics: introduce a icp_kvm_connect() routine Cédric Le Goater
2019-01-07 18:39 ` [Qemu-devel] [PATCH 08/13] spapr/rtas: modify spapr_rtas_register() to remove RTAS handlers Cédric Le Goater
2019-01-29 5:09 ` Alexey Kardashevskiy
2019-01-29 7:20 ` Cédric Le Goater
2019-01-07 18:39 ` [Qemu-devel] [PATCH 09/13] sysbus: add a sysbus_mmio_unmap() helper Cédric Le Goater
2019-01-07 18:39 ` [Qemu-devel] [PATCH 10/13] spapr: introduce routines to delete the KVM IRQ device Cédric Le Goater
2019-02-12 0:58 ` David Gibson
2019-01-07 18:39 ` [Qemu-devel] [PATCH 11/13] spapr: check for the activation of " Cédric Le Goater
2019-02-12 1:01 ` David Gibson
2019-02-12 7:12 ` Cédric Le Goater
2019-02-13 0:17 ` David Gibson
2019-01-07 18:39 ` [Qemu-devel] [PATCH 12/13] spapr/xics: ignore the lower 4K in the IRQ number space Cédric Le Goater
2019-02-12 1:06 ` David Gibson
2019-02-12 7:05 ` Cédric Le Goater
2019-02-13 1:33 ` David Gibson
2019-02-13 8:03 ` Cédric Le Goater
2019-02-13 11:27 ` [Qemu-devel] [Qemu-ppc] " Greg Kurz
2019-02-13 12:11 ` Greg Kurz
2019-01-07 18:39 ` [Qemu-devel] [PATCH 13/13] spapr: add KVM support to the 'dual' machine Cédric Le Goater
2019-02-12 1:11 ` David Gibson
2019-02-12 7:18 ` Cédric Le Goater
2019-02-13 1:32 ` David Gibson
2019-02-13 8:22 ` Cédric Le Goater
2019-02-13 10:07 ` [Qemu-devel] [Qemu-ppc] " Greg Kurz
2019-02-14 3:35 ` David Gibson
2019-02-14 7:13 ` Cédric Le Goater
2019-02-14 3:29 ` [Qemu-devel] " David Gibson
2019-02-22 12:36 ` Cédric Le Goater
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=20190212002223.GD1884@umbus.fritz.box \
--to=david@gibson.dropbear.id.au \
--cc=benh@kernel.crashing.org \
--cc=clg@kaod.org \
--cc=qemu-devel@nongnu.org \
--cc=qemu-ppc@nongnu.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.