diff options
| author | Wanpeng Li <wanpengli@tencent.com> | 2019-06-11 15:23:49 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-07-02 19:56:04 +0300 |
| commit | 715062970f3748fbbf55c1a8cb495051760a65c1 (patch) | |
| tree | a2443ef6acff1492eea3cd89caa7130f6130a88d /arch/x86/kvm/x86.c | |
| parent | f85f6e7bc9682a6d8b342c010cd6aa58521fdeec (diff) | |
| download | linux-715062970f3748fbbf55c1a8cb495051760a65c1.tar.xz | |
KVM: X86: Implement PV sched yield hypercall
The target vCPUs are in runnable state after vcpu_kick and suitable
as a yield target. This patch implements the sched yield hypercall.
17% performance increasement of ebizzy benchmark can be observed in an
over-subscribe environment. (w/ kvm-pv-tlb disabled, testing TLB flush
call-function IPI-many since call-function is not easy to be trigged
by userspace workload).
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 721af7b46b24..2e302e977dac 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7193,6 +7193,23 @@ void kvm_vcpu_deactivate_apicv(struct kvm_vcpu *vcpu) kvm_x86_ops->refresh_apicv_exec_ctrl(vcpu); } +static void kvm_sched_yield(struct kvm *kvm, unsigned long dest_id) +{ + struct kvm_vcpu *target = NULL; + struct kvm_apic_map *map; + + rcu_read_lock(); + map = rcu_dereference(kvm->arch.apic_map); + + if (likely(map) && dest_id <= map->max_apic_id && map->phys_map[dest_id]) + target = map->phys_map[dest_id]->vcpu; + + rcu_read_unlock(); + + if (target) + kvm_vcpu_yield_to(target); +} + int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) { unsigned long nr, a0, a1, a2, a3, ret; @@ -7239,6 +7256,10 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) case KVM_HC_SEND_IPI: ret = kvm_pv_send_ipi(vcpu->kvm, a0, a1, a2, a3, op_64_bit); break; + case KVM_HC_SCHED_YIELD: + kvm_sched_yield(vcpu->kvm, a0); + ret = 0; + break; default: ret = -KVM_ENOSYS; break; |