From: Greg Kurz <groug@kaod.org>
To: "Cédric Le Goater" <clg@kaod.org>
Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [PATCH for-6.0 2/8] spapr/xive: Introduce spapr_xive_nr_ends()
Date: Wed, 25 Nov 2020 13:26:03 +0100 [thread overview]
Message-ID: <20201125132603.11a0c08e@bahia.lan> (raw)
In-Reply-To: <be6b856e-1517-eb77-ae27-80a851b78168@kaod.org>
On Wed, 25 Nov 2020 12:34:25 +0100
Cédric Le Goater <clg@kaod.org> wrote:
>
> >>> This complexifies migration because we have to guess at
> >>> post load if we should claim the IPI in KVM or not. The
> >>> simple presence of the vCPU isn't enough : we need to
> >>> guess if the guest actually configured the IPI or not.
> >>
> >> The EAT will be transferred from the source and the call to
> >> kvmppc_xive_source_reset_one() should initialize the KVM
> >> device correctly on the target for all interrupts.
> >>
> >
> > Except that the EAS appears as valid for all IPIs, even
> > though the source didn't claim them at the KVM level.
>
> why ? we would stop claiming IPIs in spapr_irq_init() and so
> they won't appear as being valid anymore, at boot time or
> restore time.
>
If we don't claim the IPIs in spapr_irq_init() anymore then
we must at least claim them on the path of H_INT_GET_SOURCE_INFO
otherwise it will fail with H_P2 and the guest won't even
try to setup the IPI. Even if we do that, we still have a
window where the source is valid in QEMU but not yet at
the KVM level.
>
> C.
next prev parent reply other threads:[~2020-11-25 12:27 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 17:46 [PATCH for-6.0 0/8] spapr: Address the confusion between IPI numbers and vCPU ids Greg Kurz
2020-11-20 17:46 ` [PATCH for-6.0 1/8] spapr/xive: Turn some sanity checks into assertions Greg Kurz
2020-11-23 3:33 ` David Gibson
2020-11-23 8:09 ` Cédric Le Goater
2020-11-20 17:46 ` [PATCH for-6.0 2/8] spapr/xive: Introduce spapr_xive_nr_ends() Greg Kurz
2020-11-23 3:33 ` David Gibson
2020-11-25 22:43 ` Greg Kurz
2020-11-26 0:06 ` David Gibson
2020-11-23 9:46 ` Cédric Le Goater
2020-11-23 11:16 ` Greg Kurz
2020-11-24 13:54 ` Cédric Le Goater
2020-11-24 17:01 ` Greg Kurz
2020-11-24 17:56 ` Cédric Le Goater
2020-11-25 9:33 ` Greg Kurz
2020-11-25 11:34 ` Cédric Le Goater
2020-11-25 12:26 ` Greg Kurz [this message]
2020-11-26 7:06 ` Cédric Le Goater
2020-11-20 17:46 ` [PATCH for-6.0 3/8] spapr/xive: Add "nr-servers" property Greg Kurz
2020-11-23 3:52 ` David Gibson
2020-11-23 9:20 ` Greg Kurz
2020-11-23 9:56 ` Cédric Le Goater
2020-11-23 11:25 ` Greg Kurz
2020-11-24 14:18 ` Cédric Le Goater
2020-11-20 17:46 ` [PATCH for-6.0 4/8] spapr/xive: Add "nr-ipis" property Greg Kurz
2020-11-23 4:10 ` David Gibson
2020-11-23 10:13 ` Cédric Le Goater
2020-11-24 17:18 ` Greg Kurz
2020-11-20 17:46 ` [PATCH for-6.0 5/8] spapr/xics: Drop unused argument to xics_kvm_has_broken_disconnect() Greg Kurz
2020-11-23 4:10 ` David Gibson
2020-11-23 10:15 ` Cédric Le Goater
2020-11-20 17:46 ` [PATCH for-6.0 6/8] spapr/xics: Add "nr-servers" property Greg Kurz
2020-11-23 4:18 ` David Gibson
2020-11-23 9:39 ` Greg Kurz
2020-11-23 10:24 ` Cédric Le Goater
2020-11-20 17:46 ` [PATCH for-6.0 7/8] spapr: Drop "nr_servers" argument of the sPAPR IC activate() operation Greg Kurz
2020-11-23 4:38 ` David Gibson
2020-11-23 9:47 ` Greg Kurz
2020-11-20 17:46 ` [PATCH for-6.0 8/8] spapr: Drop "nr_servers" argument of the sPAPR IC dt() operation Greg Kurz
2020-11-23 8:04 ` [PATCH for-6.0 0/8] spapr: Address the confusion between IPI numbers and vCPU ids Cédric Le Goater
2020-11-23 10:07 ` Greg Kurz
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