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 --- arch/x86/include/asm/kvm_host.h | 1 - arch/x86/kvm/hyperv.c | 5 +---- arch/x86/kvm/x86.c | 9 +-------- include/linux/kvm_host.h | 2 +- virt/kvm/kvm_main.c | 29 +++++++++-------------------- 5 files changed, 12 insertions(+), 34 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f8f48a7ec577..120ac07e4094 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -581,7 +581,6 @@ struct kvm_vcpu_hv { struct kvm_hyperv_exit exit; struct kvm_vcpu_hv_stimer stimer[HV_SYNIC_STIMER_COUNT]; DECLARE_BITMAP(stimer_pending_bitmap, HV_SYNIC_STIMER_COUNT); - cpumask_t tlb_flush; bool enforce_cpuid; struct { u32 features_eax; /* HYPERV_CPUID_FEATURES.EAX */ diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index b4b432a164ae..6f11cda2bfa4 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1754,7 +1754,6 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool int i; gpa_t gpa; struct kvm *kvm = vcpu->kvm; - struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu); struct hv_tlb_flush_ex flush_ex; struct hv_tlb_flush flush; u64 vp_bitmap[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; @@ -1836,8 +1835,6 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool } } - cpumask_clear(&hv_vcpu->tlb_flush); - /* * vcpu->arch.cr3 may not be up-to-date for running vCPUs so we can't * analyze it here, flush TLB regardless of the specified address space. @@ -1849,7 +1846,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool vp_bitmap, vcpu_bitmap); kvm_make_vcpus_request_mask(kvm, KVM_REQ_TLB_FLUSH_GUEST, - vcpu_mask, &hv_vcpu->tlb_flush); + vcpu_mask); } ret_success: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7212ba654ba2..03568cbbe8bd 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9242,14 +9242,7 @@ static void process_smi(struct kvm_vcpu *vcpu) void kvm_make_scan_ioapic_request_mask(struct kvm *kvm, unsigned long *vcpu_bitmap) { - cpumask_var_t cpus; - - zalloc_cpumask_var(&cpus, GFP_ATOMIC); - - kvm_make_vcpus_request_mask(kvm, KVM_REQ_SCAN_IOAPIC, - vcpu_bitmap, cpus); - - free_cpumask_var(cpus); + kvm_make_vcpus_request_mask(kvm, KVM_REQ_SCAN_IOAPIC, vcpu_bitmap); } void kvm_make_scan_ioapic_request(struct kvm *kvm) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 89e1a0069833..f1b96a2ebaa7 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -160,7 +160,7 @@ static inline bool is_error_page(struct page *page) #define KVM_ARCH_REQ(nr) KVM_ARCH_REQ_FLAGS(nr, 0) bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req, - unsigned long *vcpu_bitmap, cpumask_var_t tmp); + unsigned long *vcpu_bitmap); bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req); bool kvm_make_all_cpus_request_except(struct kvm *kvm, unsigned int req, struct kvm_vcpu *except); 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 v1.2.3