From 620b2438abf98f09e19802cbc3bc2e98179cdbe2 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Fri, 3 Sep 2021 09:51:41 +0200 Subject: KVM: Make kvm_make_vcpus_request_mask() use pre-allocated cpu_kick_mask kvm_make_vcpus_request_mask() already disables preemption so just like kvm_make_all_cpus_request_except() it can be switched to using pre-allocated per-cpu cpumasks. This allows for improvements for both users of the function: in Hyper-V emulation code 'tlb_flush' can now be dropped from 'struct kvm_vcpu_hv' and kvm_make_scan_ioapic_request_mask() gets rid of dynamic allocation. cpumask_available() checks in kvm_make_vcpu_request() and kvm_kick_many_cpus() can now be dropped as they checks for an impossible condition: kvm_init() makes sure per-cpu masks are allocated. Signed-off-by: Vitaly Kuznetsov Reviewed-by: Sean Christopherson Signed-off-by: Paolo Bonzini Message-Id: <20210903075141.403071-9-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini --- virt/kvm/kvm_main.c | 29 +++++++++-------------------- 1 file changed, 9 insertions(+), 20 deletions(-) (limited to 'virt') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 9cb0fd1723e6..18d245fe2118 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -237,15 +237,8 @@ static void ack_flush(void *_completed) { } -static inline bool kvm_kick_many_cpus(cpumask_var_t tmp, bool wait) +static inline bool kvm_kick_many_cpus(struct cpumask *cpus, bool wait) { - const struct cpumask *cpus; - - if (likely(cpumask_available(tmp))) - cpus = tmp; - else - cpus = cpu_online_mask; - if (cpumask_empty(cpus)) return false; @@ -254,7 +247,7 @@ static inline bool kvm_kick_many_cpus(cpumask_var_t tmp, bool wait) } static void kvm_make_vcpu_request(struct kvm *kvm, struct kvm_vcpu *vcpu, - unsigned int req, cpumask_var_t tmp, + unsigned int req, struct cpumask *tmp, int current_cpu) { int cpu; @@ -264,14 +257,6 @@ static void kvm_make_vcpu_request(struct kvm *kvm, struct kvm_vcpu *vcpu, if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu)) return; - /* - * tmp can be "unavailable" if cpumasks are allocated off stack as - * allocation of the mask is deliberately not fatal and is handled by - * falling back to kicking all online CPUs. - */ - if (!cpumask_available(tmp)) - return; - /* * Note, the vCPU could get migrated to a different pCPU at any point * after kvm_request_needs_ipi(), which could result in sending an IPI @@ -290,22 +275,26 @@ static void kvm_make_vcpu_request(struct kvm *kvm, struct kvm_vcpu *vcpu, } bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req, - unsigned long *vcpu_bitmap, cpumask_var_t tmp) + unsigned long *vcpu_bitmap) { struct kvm_vcpu *vcpu; + struct cpumask *cpus; int i, me; bool called; me = get_cpu(); + cpus = this_cpu_cpumask_var_ptr(cpu_kick_mask); + cpumask_clear(cpus); + for_each_set_bit(i, vcpu_bitmap, KVM_MAX_VCPUS) { vcpu = kvm_get_vcpu(kvm, i); if (!vcpu) continue; - kvm_make_vcpu_request(kvm, vcpu, req, tmp, me); + kvm_make_vcpu_request(kvm, vcpu, req, cpus, me); } - called = kvm_kick_many_cpus(tmp, !!(req & KVM_REQUEST_WAIT)); + called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT)); put_cpu(); return called; -- cgit