On 26/04/2017 09:00, David Gibson wrote:
> From: Cédric Le Goater <c...@kaod.org>
>
> Today, all the ICPs are created before the CPUs, stored in an array
> under the sPAPR machine and linked to the CPU when the core threads
> are realized. This modeling brings some complexity when a lookup in
> the array is required and it can be simplified by allocating the ICPs
> when the CPUs are.
>
> This is the purpose of this proposal which introduces a new 'icp_type'
> field under the machine and creates the ICP objects of the right type
> (KVM or not) before the PowerPCCPU object are.
>
> This change allows more cleanups : the removal of the icps array under
> the sPAPR machine and the removal of the xics_get_cpu_index_by_dt_id()
> helper.
>
> Signed-off-by: Cédric Le Goater <c...@kaod.org>
> Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>
> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
> ---
> hw/intc/xics.c | 11 -----------
> hw/ppc/spapr.c | 47 ++++++++++++++---------------------------------
> hw/ppc/spapr_cpu_core.c | 18 ++++++++++++++----
> include/hw/ppc/spapr.h | 2 +-
> include/hw/ppc/xics.h | 2 --
> 5 files changed, 29 insertions(+), 51 deletions(-)
>
This commit breaks CPU re-hotplugging with KVM
the sequence "device_add, device_del, device_add" brings to the
following error message:
Unable to connect CPUx to kernel XICS: Device or resource busy
It comes from icp_kvm_cpu_setup():
...
ret = kvm_vcpu_enable_cap(cs, KVM_CAP_IRQ_XICS, 0, kernel_xics_fd,
kvm_arch_vcpu_id(cs));
if (ret < 0) {
error_report("Unable to connect CPU%ld to kernel XICS: %s",
kvm_arch_vcpu_id(cs), strerror(errno));
exit(1);
}
..
It should be protected by cap_irq_xics_enabled:
...
/*
* 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 (icp->cap_irq_xics_enabled) {
return;
}
...
ret = kvm_vcpu_enable_cap(...);
...
icp->cap_irq_xics_enabled = true;
...
But since this commit, "icp" is a new object on each call:
spapr_cpu_core_realize_child()
...
obj = object_new(spapr->icp_type);
...
xics_cpu_setup(XICS_FABRIC(spapr), cpu, ICP(obj));
...
icpc->cpu_setup(icp, cpu); -> icp_kvm_cpu_setup()
...
...
and "cap_irq_xics_enabled" is reinitialized.
Any idea how to fix that?
Thanks,
Laurent
