On Thu, Oct 03, 2019 at 02:02:00PM +0200, Greg Kurz wrote: > Support for setting VSMT is available in KVM since linux-4.13. Most distros > that support KVM on POWER already have it. It thus seem reasonable enough > to have the default machine to set VSMT to smp_threads. > > This brings contiguous VCPU ids and thus brings their upper bound down to > the machine's max_cpus. This is especially useful for XIVE KVM devices, > which may thus allocate only one VP descriptor per VCPU. > > Signed-off-by: Greg Kurz <gr...@kaod.org>
Applied to ppc-for-4.2, thanks.
> ---
> hw/ppc/spapr.c | 7 ++++++-
> include/hw/ppc/spapr.h | 1 +
> 2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 8f59f08c102e..473ce1d04775 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -2503,6 +2503,7 @@ static CPUArchId *spapr_find_cpu_slot(MachineState *ms,
> uint32_t id, int *idx)
> static void spapr_set_vsmt_mode(SpaprMachineState *spapr, Error **errp)
> {
> MachineState *ms = MACHINE(spapr);
> + SpaprMachineClass *smc = SPAPR_MACHINE_GET_CLASS(spapr);
> Error *local_err = NULL;
> bool vsmt_user = !!spapr->vsmt;
> int kvm_smt = kvmppc_smt_threads();
> @@ -2529,7 +2530,7 @@ static void spapr_set_vsmt_mode(SpaprMachineState
> *spapr, Error **errp)
> goto out;
> }
> /* In this case, spapr->vsmt has been set by the command line */
> - } else {
> + } else if (!smc->smp_threads_vsmt) {
> /*
> * Default VSMT value is tricky, because we need it to be as
> * consistent as possible (for migration), but this requires
> @@ -2538,6 +2539,8 @@ static void spapr_set_vsmt_mode(SpaprMachineState
> *spapr, Error **errp)
> * overwhelmingly common case in production systems.
> */
> spapr->vsmt = MAX(8, smp_threads);
> + } else {
> + spapr->vsmt = smp_threads;
> }
>
> /* KVM: If necessary, set the SMT mode: */
> @@ -4452,6 +4455,7 @@ static void spapr_machine_class_init(ObjectClass *oc,
> void *data)
> smc->irq = &spapr_irq_dual;
> smc->dr_phb_enabled = true;
> smc->linux_pci_probe = true;
> + smc->smp_threads_vsmt = true;
> }
>
> static const TypeInfo spapr_machine_info = {
> @@ -4519,6 +4523,7 @@ static void
> spapr_machine_4_1_class_options(MachineClass *mc)
>
> spapr_machine_4_2_class_options(mc);
> smc->linux_pci_probe = false;
> + smc->smp_threads_vsmt = false;
> compat_props_add(mc->compat_props, hw_compat_4_1, hw_compat_4_1_len);
> compat_props_add(mc->compat_props, compat, G_N_ELEMENTS(compat));
> }
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index cbd1a4c9f390..2009eb64f9cb 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -122,6 +122,7 @@ struct SpaprMachineClass {
> bool broken_host_serial_model; /* present real host info to the guest */
> bool pre_4_1_migration; /* don't migrate hpt-max-page-size */
> bool linux_pci_probe;
> + bool smp_threads_vsmt; /* set VSMT to smp_threads by default */
>
> void (*phb_placement)(SpaprMachineState *spapr, uint32_t index,
> uint64_t *buid, hwaddr *pio,
>
--
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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