diff options
| author | Paul Mackerras <paulus@ozlabs.org> | 2017-02-06 13:24:41 +1100 |
|---|---|---|
| committer | Paul Mackerras <paulus@ozlabs.org> | 2017-06-19 14:34:20 +1000 |
| commit | 3c313524605a6afd8207448a8e9967f5e8cba734 (patch) | |
| tree | 618ce202f550dccba853ec66b75c973a976cf833 /arch/powerpc/include | |
| parent | 769377f77ca2087baeaf97ce0b7026abeba3b581 (diff) | |
KVM: PPC: Book3S HV: Allow userspace to set the desired SMT mode
This allows userspace to set the desired virtual SMT (simultaneous
multithreading) mode for a VM, that is, the number of VCPUs that
get assigned to each virtual core. Previously, the virtual SMT mode
was fixed to the number of threads per subcore, and if userspace
wanted to have fewer vcpus per vcore, then it would achieve that by
using a sparse CPU numbering. This had the disadvantage that the
vcpu numbers can get quite large, particularly for SMT1 guests on
a POWER8 with 8 threads per core. With this patch, userspace can
set its desired virtual SMT mode and then use contiguous vcpu
numbering.
On POWER8, where the threading mode is "strict", the virtual SMT mode
must be less than or equal to the number of threads per subcore. On
POWER9, which implements a "loose" threading mode, the virtual SMT
mode can be any power of 2 between 1 and 8, even though there is
effectively one thread per subcore, since the threads are independent
and can all be in different partitions.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch/powerpc/include')
| -rw-r--r-- | arch/powerpc/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/kvm_ppc.h | 2 |
2 files changed, 3 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index d3aae32acb54..e8991808ea9c 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -267,6 +267,7 @@ struct kvm_resize_hpt; struct kvm_arch { unsigned int lpid; + unsigned int smt_mode; /* # vcpus per virtual core */ #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE unsigned int tlb_sets; struct kvm_hpt_info hpt; diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index e0d88c38602b..ba5fadd6f3c9 100644 --- a/arch/powerpc/include/asm/kvm_ppc.h +++ b/arch/powerpc/include/asm/kvm_ppc.h @@ -315,6 +315,8 @@ struct kvmppc_ops { struct irq_bypass_producer *); int (*configure_mmu)(struct kvm *kvm, struct kvm_ppc_mmuv3_cfg *cfg); int (*get_rmmu_info)(struct kvm *kvm, struct kvm_ppc_rmmu_info *info); + int (*set_smt_mode)(struct kvm *kvm, unsigned long mode, + unsigned long flags); }; extern struct kvmppc_ops *kvmppc_hv_ops; |