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KVM: x86: hyperv: optimize 'all cpus' case in kvm_hv_flush_tlb() 

We can use 'NULL' to represent 'all cpus' case in
kvm_make_vcpus_request_mask() and avoid building vCPU mask with
all vCPUs.

Suggested-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Vitaly Kuznetsov 2018-08-22 12:18:29 +02:00 committed by Paolo Bonzini
parent 9170200ec0
commit a812297c4f
2 changed files with 25 additions and 23 deletions
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42
arch/x86/kvm/hyperv.c
View File

@ -1325,35 +1325,39 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa,
cpumask_clear(&hv_current->tlb_lush); cpumask_clear(&hv_current->tlb_lush);
if (all_cpus) {
kvm_make_vcpus_request_mask(kvm,
KVM_REQ_TLB_FLUSH | KVM_REQUEST_NO_WAKEUP,
NULL, &hv_current->tlb_lush);
goto ret_success;
}
kvm_for_each_vcpu(i, vcpu, kvm) { kvm_for_each_vcpu(i, vcpu, kvm) {
struct kvm_vcpu_hv *hv = &vcpu->arch.hyperv; struct kvm_vcpu_hv *hv = &vcpu->arch.hyperv;
int bank = hv->vp_index / 64, sbank = 0; int bank = hv->vp_index / 64, sbank = 0;
if (!all_cpus) { /* Banks >64 can't be represented */
/* Banks >64 can't be represented */ if (bank >= 64)
if (bank >= 64) continue;
continue;
/* Non-ex hypercalls can only address first 64 vCPUs */ /* Non-ex hypercalls can only address first 64 vCPUs */
if (!ex && bank) if (!ex && bank)
continue; continue;
if (ex) { if (ex) {
/* /*
* Check is the bank of this vCPU is in sparse * Check is the bank of this vCPU is in sparse
* set and get the sparse bank number. * set and get the sparse bank number.
*/ */
sbank = get_sparse_bank_no(valid_bank_mask, sbank = get_sparse_bank_no(valid_bank_mask, bank);
bank);
if (sbank < 0) if (sbank < 0)
continue;
}
if (!(sparse_banks[sbank] & BIT_ULL(hv->vp_index % 64)))
continue; continue;
} }
if (!(sparse_banks[sbank] & BIT_ULL(hv->vp_index % 64)))
continue;
/* /*
* vcpu->arch.cr3 may not be up-to-date for running vCPUs so we * 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 * can't analyze it here, flush TLB regardless of the specified

6
virt/kvm/kvm_main.c
View File

@ -219,7 +219,7 @@ bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
me = get_cpu(); me = get_cpu();
kvm_for_each_vcpu(i, vcpu, kvm) { kvm_for_each_vcpu(i, vcpu, kvm) {
if (!test_bit(i, vcpu_bitmap)) if (vcpu_bitmap && !test_bit(i, vcpu_bitmap))
continue; continue;
kvm_make_request(req, vcpu); kvm_make_request(req, vcpu);
@ -243,12 +243,10 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
{ {
cpumask_var_t cpus; cpumask_var_t cpus;
bool called; bool called;
static unsigned long vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)]
= {[0 ... BITS_TO_LONGS(KVM_MAX_VCPUS)-1] = ULONG_MAX};
zalloc_cpumask_var(&cpus, GFP_ATOMIC); zalloc_cpumask_var(&cpus, GFP_ATOMIC);
called = kvm_make_vcpus_request_mask(kvm, req, vcpu_bitmap, cpus); called = kvm_make_vcpus_request_mask(kvm, req, NULL, cpus);
free_cpumask_var(cpus); free_cpumask_var(cpus);
return called; return called;