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Re: [Qemu-ppc] [PATCH 06/13] spapr/xive: fix migration of the XiveTCTX u
From: |
David Gibson |
Subject: |
Re: [Qemu-ppc] [PATCH 06/13] spapr/xive: fix migration of the XiveTCTX under TCG |
Date: |
Fri, 8 Feb 2019 16:36:07 +1100 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
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 <address@hidden>
Why is the CAM value you get from KVM different from the one you
expect in qemu?
> ---
> 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 233c97c5ecd9..ba27d9d8e972 100644
> --- a/hw/ppc/spapr_irq.c
> +++ b/hw/ppc/spapr_irq.c
> @@ -363,7 +363,31 @@ 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(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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- Re: [Qemu-ppc] [PATCH 06/13] spapr/xive: fix migration of the XiveTCTX under TCG,
David Gibson <=