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KVM: x86: hyperv: optimize kvm_hv_flush_tlb() for vp_index == vcpu_idx case 

VP inedx almost always matches VCPU and when it does it's faster to walk
the sparse set instead of all vcpus.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hifive-unleashed-5.1
Vitaly Kuznetsov 2018-09-26 19:02:58 +02:00 committed by Paolo Bonzini
parent 0b0a31badb
commit 2cefc5feb8
1 changed files with 53 additions and 45 deletions
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98
arch/x86/kvm/hyperv.c
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@ -1277,32 +1277,37 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host)
return kvm_hv_get_msr(vcpu, msr, pdata, host);
}
static __always_inline int get_sparse_bank_no(u64 valid_bank_mask, int bank_no)
static __always_inline bool hv_vcpu_in_sparse_set(struct kvm_vcpu_hv *hv_vcpu,
u64 sparse_banks[],
u64 valid_bank_mask)
{
int i = 0, j;
int bank = hv_vcpu->vp_index / 64, sbank;
if (!(valid_bank_mask & BIT_ULL(bank_no)))
return -1;
if (bank >= 64)
return false;
for (j = 0; j < bank_no; j++)
if (valid_bank_mask & BIT_ULL(j))
i++;
if (!(valid_bank_mask & BIT_ULL(bank)))
return false;
return i;
/* Sparse bank number equals to the number of set bits before it */
sbank = bitmap_weight((unsigned long *)&valid_bank_mask, bank);
return !!(sparse_banks[sbank] & BIT_ULL(hv_vcpu->vp_index % 64));
}
static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa,
u16 rep_cnt, bool ex)
{
struct kvm *kvm = current_vcpu->kvm;
struct kvm_vcpu_hv *hv_current = &current_vcpu->arch.hyperv;
struct kvm_hv *hv = &kvm->arch.hyperv;
struct kvm_vcpu_hv *hv_vcpu = &current_vcpu->arch.hyperv;
struct hv_tlb_flush_ex flush_ex;
struct hv_tlb_flush flush;
struct kvm_vcpu *vcpu;
unsigned long vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)] = {0};
u64 valid_bank_mask = 0;
u64 valid_bank_mask;
u64 sparse_banks[64];
int sparse_banks_len, i;
int sparse_banks_len, i, bank, sbank;
bool all_cpus;
if (!ex) {
@ -1312,6 +1317,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa,
trace_kvm_hv_flush_tlb(flush.processor_mask,
flush.address_space, flush.flags);
valid_bank_mask = BIT_ULL(0);
sparse_banks[0] = flush.processor_mask;
all_cpus = flush.flags & HV_FLUSH_ALL_PROCESSORS;
} else {
@ -1344,52 +1350,54 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa,
return HV_STATUS_INVALID_HYPERCALL_INPUT;
}
cpumask_clear(&hv_current->tlb_lush);
/*
* 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.
*/
cpumask_clear(&hv_vcpu->tlb_lush);
if (all_cpus) {
kvm_make_vcpus_request_mask(kvm,
KVM_REQ_TLB_FLUSH | KVM_REQUEST_NO_WAKEUP,
NULL, &hv_current->tlb_lush);
NULL, &hv_vcpu->tlb_lush);
goto ret_success;
}
kvm_for_each_vcpu(i, vcpu, kvm) {
struct kvm_vcpu_hv *hv = &vcpu->arch.hyperv;
int bank = hv->vp_index / 64, sbank = 0;
/* Banks >64 can't be represented */
if (bank >= 64)
continue;
/* Non-ex hypercalls can only address first 64 vCPUs */
if (!ex && bank)
continue;
if (ex) {
/*
* Check is the bank of this vCPU is in sparse
* set and get the sparse bank number.
*/
sbank = get_sparse_bank_no(valid_bank_mask, bank);
if (sbank < 0)
continue;
if (atomic_read(&hv->num_mismatched_vp_indexes)) {
kvm_for_each_vcpu(i, vcpu, kvm) {
if (hv_vcpu_in_sparse_set(&vcpu->arch.hyperv,
sparse_banks,
valid_bank_mask))
__set_bit(i, vcpu_bitmap);
}
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
* can't analyze it here, flush TLB regardless of the specified
* address space.
*/
__set_bit(i, vcpu_bitmap);
goto flush_request;
}
/*
* num_mismatched_vp_indexes is zero so every vcpu has
* vp_index == vcpu_idx.
*/
sbank = 0;
for_each_set_bit(bank, (unsigned long *)&valid_bank_mask,
BITS_PER_LONG) {
for_each_set_bit(i,
(unsigned long *)&sparse_banks[sbank],
BITS_PER_LONG) {
u32 vp_index = bank * 64 + i;
/* A non-existent vCPU was specified */
if (vp_index >= KVM_MAX_VCPUS)
return HV_STATUS_INVALID_HYPERCALL_INPUT;
__set_bit(vp_index, vcpu_bitmap);
}
sbank++;
}
flush_request:
kvm_make_vcpus_request_mask(kvm,
KVM_REQ_TLB_FLUSH | KVM_REQUEST_NO_WAKEUP,
vcpu_bitmap, &hv_current->tlb_lush);
vcpu_bitmap, &hv_vcpu->tlb_lush);
ret_success:
/* We always do full TLB flush, set rep_done = rep_cnt. */