Re: [Qemu-devel] [PATCH 5/5] spapr: drop DIV_ROUND_UP() from xics_max_server_number()

2018-02-15 Thread Greg Kurz
On Thu, 15 Feb 2018 16:54:18 + Daniel P. Berrangé wrote: > On Thu, Feb 15, 2018 at 05:08:57PM +0100, Greg Kurz wrote: > > On Thu, 15 Feb 2018 15:08:18 +1100 > > David Gibson wrote: > > > > > On Wed, Feb 14, 2018 at 08:41:03PM +0100, Greg

Re: [Qemu-devel] [PATCH 5/5] spapr: drop DIV_ROUND_UP() from xics_max_server_number()

2018-02-15 Thread Daniel P . Berrangé
On Thu, Feb 15, 2018 at 05:08:57PM +0100, Greg Kurz wrote: > On Thu, 15 Feb 2018 15:08:18 +1100 > David Gibson wrote: > > > On Wed, Feb 14, 2018 at 08:41:03PM +0100, Greg Kurz wrote: > > > > > > > > > It breaks migration of pre-2.7 machine types with unusual CPU

Re: [Qemu-devel] [PATCH 5/5] spapr: drop DIV_ROUND_UP() from xics_max_server_number()

2018-02-15 Thread Greg Kurz
On Thu, 15 Feb 2018 15:08:18 +1100 David Gibson wrote: > On Wed, Feb 14, 2018 at 08:41:03PM +0100, Greg Kurz wrote: > > > > It breaks migration of pre-2.7 machine types with unusual CPU topologies, > > but I guess this is an acceptable trade-off. > > No, not

Re: [Qemu-devel] [PATCH 5/5] spapr: drop DIV_ROUND_UP() from xics_max_server_number()

2018-02-14 Thread David Gibson
On Wed, Feb 14, 2018 at 08:41:03PM +0100, Greg Kurz wrote: > XICS needs to know the highest VCPU id that may be presented to the > guest plus 1. Commit f303f117fec3 "spapr: ensure we have at least one > XICS server" changed how the maximum is computed from: > > smp_cpus *

[Qemu-devel] [PATCH 5/5] spapr: drop DIV_ROUND_UP() from xics_max_server_number()

2018-02-14 Thread Greg Kurz
XICS needs to know the highest VCPU id that may be presented to the guest plus 1. Commit f303f117fec3 "spapr: ensure we have at least one XICS server" changed how the maximum is computed from: smp_cpus * kvmppc_smt_threads() / smp_threads to: DIV_ROUND_UP(smp_cpus *