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 <clg@kaod.org>
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_!
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