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Re: [Qemu-devel] [PATCH v2 07/13] spapr/xive: fix migration of the XiveT
From: |
David Gibson |
Subject: |
Re: [Qemu-devel] [PATCH v2 07/13] spapr/xive: fix migration of the XiveTCTX under TCG |
Date: |
Tue, 26 Feb 2019 12:02:46 +1100 |
User-agent: |
Mutt/1.11.3 (2019-02-01) |
On Fri, Feb 22, 2019 at 02:13:16PM +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 <address@hidden>
As noted elsewhere, I'm not sure this is the right approach to fixing
this. In any case this can be folded into the previous patch.
> ---
> hw/ppc/spapr_irq.c | 26 +++++++++++++++++++++++++-
> 1 file changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
> index 12ecca6264f3..3176098b9f7c 100644
> --- a/hw/ppc/spapr_irq.c
> +++ b/hw/ppc/spapr_irq.c
> @@ -356,7 +356,31 @@ static void
> spapr_irq_cpu_intc_create_xive(sPAPRMachineState *spapr,
>
> static int spapr_irq_post_load_xive(sPAPRMachineState *spapr, int version_id)
> {
> - return spapr_xive_post_load(spapr->xive, version_id);
> + CPUState *cs;
> + int ret;
> +
> + ret = spapr_xive_post_load(spapr->xive, version_id);
> + if (ret) {
> + return ret;
> + }
> +
> + /*
> + * When the states are collected from the KVM XIVE device, word2
> + * of the XiveTCTX is set to print out the OS CAM line under the
> + * QEMU monitor.
> + *
> + * This breaks the migration on a TCG guest (or on KVM with
> + * 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.
> + */
> + CPU_FOREACH(cs) {
> + PowerPCCPU *cpu = POWERPC_CPU(cs);
> +
> + /* (TCG) Set the OS CAM line of the thread interrupt context. */
> + spapr_xive_set_tctx_os_cam(spapr_cpu_state(cpu)->tctx);
> + }
> + return 0;
> }
>
> static void spapr_irq_reset_xive(sPAPRMachineState *spapr, Error **errp)
--
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
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- [Qemu-devel] [PATCH v2 03/13] spapr/xive: activate KVM support, (continued)
- [Qemu-devel] [PATCH v2 03/13] spapr/xive: activate KVM support, Cédric Le Goater, 2019/02/22
- [Qemu-devel] [PATCH v2 01/13] spapr/xive: add KVM support, Cédric Le Goater, 2019/02/22
- [Qemu-devel] [PATCH v2 13/13] spapr/xive: fix device hotplug when VM is stopped, Cédric Le Goater, 2019/02/22
- [Qemu-devel] [PATCH v2 12/13] spapr: add KVM support to the 'dual' machine, Cédric Le Goater, 2019/02/22
- [Qemu-devel] [PATCH v2 02/13] spapr/xive: add hcall support when under KVM, Cédric Le Goater, 2019/02/22
- [Qemu-devel] [PATCH v2 07/13] spapr/xive: fix migration of the XiveTCTX under TCG, Cédric Le Goater, 2019/02/22
- Re: [Qemu-devel] [PATCH v2 07/13] spapr/xive: fix migration of the XiveTCTX under TCG,
David Gibson <=
- [Qemu-devel] [PATCH v2 04/13] spapr/xive: add state synchronization with KVM, Cédric Le Goater, 2019/02/22
- [Qemu-devel] [PATCH v2 09/13] sysbus: add a sysbus_mmio_unmap() helper, Cédric Le Goater, 2019/02/22
- [Qemu-devel] [PATCH v2 06/13] spapr/xive: add migration support for KVM, Cédric Le Goater, 2019/02/22
- [Qemu-devel] [PATCH v2 10/13] spapr: introduce routines to delete the KVM IRQ device, Cédric Le Goater, 2019/02/22