On Mon, Mar 23, 2015 at 07:05:58PM +0530, Bharata B Rao wrote: > When supporting CPU hot removal by parking the vCPU fd and reusing > it during hotplug again, there can be cases where we try to reenable > KVM_CAP_IRQ_XICS CAP for the vCPU for which it was already enabled. > Introduce a boolean member in ICPState to track this and don't > reenable the CAP if it was already enabled earlier. > > This change allows CPU hot removal to work for sPAPR. > > Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com>
Why does double enabling the capability cause problems? I would have
expected it to be unnecessary, but harmless.
> ---
> hw/intc/xics_kvm.c | 10 ++++++++++
> include/hw/ppc/xics.h | 1 +
> 2 files changed, 11 insertions(+)
>
> diff --git a/hw/intc/xics_kvm.c b/hw/intc/xics_kvm.c
> index c15453f..5b27bf8 100644
> --- a/hw/intc/xics_kvm.c
> +++ b/hw/intc/xics_kvm.c
> @@ -331,6 +331,15 @@ static void xics_kvm_cpu_setup(XICSState *icp,
> PowerPCCPU *cpu)
> abort();
> }
>
> + /*
> + * If we are reusing a parked vCPU fd corresponding to the CPU
> + * which was hot-removed earlier we don't have to renable
> + * KVM_CAP_IRQ_XICS capability again.
> + */
> + if (ss->cap_irq_xics_enabled) {
> + return;
> + }
> +
> if (icpkvm->kernel_xics_fd != -1) {
> int ret;
>
> @@ -343,6 +352,7 @@ static void xics_kvm_cpu_setup(XICSState *icp, PowerPCCPU
> *cpu)
> kvm_arch_vcpu_id(cs), strerror(errno));
> exit(1);
> }
> + ss->cap_irq_xics_enabled = true;
> }
> }
>
> diff --git a/include/hw/ppc/xics.h b/include/hw/ppc/xics.h
> index a214dd7..355a966 100644
> --- a/include/hw/ppc/xics.h
> +++ b/include/hw/ppc/xics.h
> @@ -109,6 +109,7 @@ struct ICPState {
> uint8_t pending_priority;
> uint8_t mfrr;
> qemu_irq output;
> + bool cap_irq_xics_enabled;
> };
>
> #define TYPE_ICS "ics"
--
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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