[PATCH v2 3/5] KVM: x86: hyperv: use vp_idx_to_vcpu_idx() in kvm_hv_flush_tlb()

Vitaly Kuznetsov
2018-06-28T13:53:11Z

As we now have a fast way to get vCPU index from VP number we can
avoid walking through all vCPUs in kvm_hv_flush_tlb().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
arch/x86/kvm/hyperv.c | 59 ++++++++++++++-------------------------------------
1 file changed, 16 insertions(+), 43 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index d676335a5448..9983304d6664 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1395,20 +1395,6 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
return kvm_hv_get_msr(vcpu, msr, pdata);
}

-static __always_inline int get_sparse_bank_no(u64 valid_bank_mask, int bank_no)
-{
- int i = 0, j;
-
- if (!(valid_bank_mask & BIT_ULL(bank_no)))
- return -1;
-
- for (j = 0; j < bank_no; j++)
- if (valid_bank_mask & BIT_ULL(j))
- i++;
-
- return i;
-}
-
static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa,
u16 rep_cnt, bool ex)
{
@@ -1416,11 +1402,10 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa,
struct kvm_vcpu_hv *hv_current = &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};
- unsigned long valid_bank_mask = 0;
+ unsigned long valid_bank_mask;
u64 sparse_banks[64];
- int sparse_banks_len, i;
+ int sparse_banks_len, bank, i;
bool all_cpus;

if (!ex) {
@@ -1430,6 +1415,7 @@ 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 {
@@ -1470,38 +1456,25 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa,
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;
+ for_each_set_bit(bank, (unsigned long *)&valid_bank_mask,
+ BITS_PER_LONG) {

- /* Banks >64 can't be represented */
- if (bank >= 64)
- continue;
+ for_each_set_bit(i, (unsigned long *)&sparse_banks[bank],
+ BITS_PER_LONG) {
+ u32 vp_index = bank * 64 + i;
+ u32 vcpu_idx = vp_idx_to_vcpu_idx(kvm, vp_index);

- /* Non-ex hypercalls can only address first 64 vCPUs */
- if (!ex && bank)
- continue;
+ /* A non-existent vCPU was specified */
+ if (vcpu_idx >= atomic_read(&kvm->online_vcpus))
+ return HV_STATUS_INVALID_HYPERCALL_INPUT;

- if (ex) {
/*
- * Check is the bank of this vCPU is in sparse
- * set and get the sparse bank number.
+ * 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.
*/
- sbank = get_sparse_bank_no(valid_bank_mask, bank);
-
- if (sbank < 0)
- continue;
+ __set_bit(vcpu_idx, 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);
}

kvm_make_vcpus_request_mask(kvm,
--
2.14.4