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KVM: x86: hyperv: optimize sparse VP set processing
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Rewrite kvm_hv_flush_tlb()/send_ipi_vcpus_mask() making them cleaner and
somewhat more optimal.

hv_vcpu_in_sparse_set() is converted to sparse_set_to_vcpu_mask()
which copies sparse banks u64-at-a-time and then, depending on the
num_mismatched_vp_indexes value, returns immediately or does
vp index to vcpu index conversion by walking all vCPUs.

To support the change and make kvm_hv_send_ipi() look similar to
kvm_hv_flush_tlb() send_ipi_vcpus_mask() is introduced.

Suggested-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Vitaly Kuznetsov authored and Paolo Bonzini committed Oct 16, 2018
1 parent e6b6c48 commit f21dd49
Showing 1 changed file with 67 additions and 98 deletions.
165 changes: 67 additions & 98 deletions arch/x86/kvm/hyperv.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,8 @@

#include "trace.h"

#define KVM_HV_MAX_SPARSE_VCPU_SET_BITS DIV_ROUND_UP(KVM_MAX_VCPUS, 64)

static inline u64 synic_read_sint(struct kvm_vcpu_hv_synic *synic, int sint)
{
return atomic64_read(&synic->sint[sint]);
Expand Down Expand Up @@ -1277,37 +1279,47 @@ 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 bool hv_vcpu_in_sparse_set(struct kvm_vcpu_hv *hv_vcpu,
u64 sparse_banks[],
u64 valid_bank_mask)
static __always_inline unsigned long *sparse_set_to_vcpu_mask(
struct kvm *kvm, u64 *sparse_banks, u64 valid_bank_mask,
u64 *vp_bitmap, unsigned long *vcpu_bitmap)
{
int bank = hv_vcpu->vp_index / 64, sbank;

if (bank >= 64)
return false;
struct kvm_hv *hv = &kvm->arch.hyperv;
struct kvm_vcpu *vcpu;
int i, bank, sbank = 0;

if (!(valid_bank_mask & BIT_ULL(bank)))
return false;
memset(vp_bitmap, 0,
KVM_HV_MAX_SPARSE_VCPU_SET_BITS * sizeof(*vp_bitmap));
for_each_set_bit(bank, (unsigned long *)&valid_bank_mask,
KVM_HV_MAX_SPARSE_VCPU_SET_BITS)
vp_bitmap[bank] = sparse_banks[sbank++];

/* Sparse bank number equals to the number of set bits before it */
sbank = bitmap_weight((unsigned long *)&valid_bank_mask, bank);
if (likely(!atomic_read(&hv->num_mismatched_vp_indexes))) {
/* for all vcpus vp_index == vcpu_idx */
return (unsigned long *)vp_bitmap;
}

return !!(sparse_banks[sbank] & BIT_ULL(hv_vcpu->vp_index % 64));
bitmap_zero(vcpu_bitmap, KVM_MAX_VCPUS);
kvm_for_each_vcpu(i, vcpu, kvm) {
if (test_bit(vcpu_to_hv_vcpu(vcpu)->vp_index,
(unsigned long *)vp_bitmap))
__set_bit(i, vcpu_bitmap);
}
return vcpu_bitmap;
}

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_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 vp_bitmap[KVM_HV_MAX_SPARSE_VCPU_SET_BITS];
DECLARE_BITMAP(vcpu_bitmap, KVM_MAX_VCPUS);
unsigned long *vcpu_mask;
u64 valid_bank_mask;
u64 sparse_banks[64];
int sparse_banks_len, i, bank, sbank;
int sparse_banks_len;
bool all_cpus;

if (!ex) {
Expand Down Expand Up @@ -1350,73 +1362,58 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa,
return HV_STATUS_INVALID_HYPERCALL_INPUT;
}

/*
* 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_flush);

if (all_cpus) {
kvm_make_vcpus_request_mask(kvm,
KVM_REQ_TLB_FLUSH | KVM_REQUEST_NO_WAKEUP,
NULL, &hv_vcpu->tlb_flush);
goto ret_success;
}

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);
}
goto flush_request;
}
vcpu_mask = all_cpus ? NULL :
sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask,
vp_bitmap, vcpu_bitmap);

/*
* num_mismatched_vp_indexes is zero so every vcpu has
* vp_index == vcpu_idx.
* 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 = 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_vcpu->tlb_flush);
vcpu_mask, &hv_vcpu->tlb_flush);

ret_success:
/* We always do full TLB flush, set rep_done = rep_cnt. */
return (u64)HV_STATUS_SUCCESS |
((u64)rep_cnt << HV_HYPERCALL_REP_COMP_OFFSET);
}

static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector,
unsigned long *vcpu_bitmap)
{
struct kvm_lapic_irq irq = {
.delivery_mode = APIC_DM_FIXED,
.vector = vector
};
struct kvm_vcpu *vcpu;
int i;

kvm_for_each_vcpu(i, vcpu, kvm) {
if (vcpu_bitmap && !test_bit(i, vcpu_bitmap))
continue;

/* We fail only when APIC is disabled */
kvm_apic_set_irq(vcpu, &irq, NULL);
}
}

static u64 kvm_hv_send_ipi(struct kvm_vcpu *current_vcpu, u64 ingpa, u64 outgpa,
bool ex, bool fast)
{
struct kvm *kvm = current_vcpu->kvm;
struct kvm_hv *hv = &kvm->arch.hyperv;
struct hv_send_ipi_ex send_ipi_ex;
struct hv_send_ipi send_ipi;
struct kvm_vcpu *vcpu;
u64 vp_bitmap[KVM_HV_MAX_SPARSE_VCPU_SET_BITS];
DECLARE_BITMAP(vcpu_bitmap, KVM_MAX_VCPUS);
unsigned long *vcpu_mask;
unsigned long valid_bank_mask;
u64 sparse_banks[64];
int sparse_banks_len, bank, i, sbank;
struct kvm_lapic_irq irq = {.delivery_mode = APIC_DM_FIXED};
int sparse_banks_len;
u32 vector;
bool all_cpus;

if (!ex) {
Expand All @@ -1425,18 +1422,18 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *current_vcpu, u64 ingpa, u64 outgpa,
sizeof(send_ipi))))
return HV_STATUS_INVALID_HYPERCALL_INPUT;
sparse_banks[0] = send_ipi.cpu_mask;
irq.vector = send_ipi.vector;
vector = send_ipi.vector;
} else {
/* 'reserved' part of hv_send_ipi should be 0 */
if (unlikely(ingpa >> 32 != 0))
return HV_STATUS_INVALID_HYPERCALL_INPUT;
sparse_banks[0] = outgpa;
irq.vector = (u32)ingpa;
vector = (u32)ingpa;
}
all_cpus = false;
valid_bank_mask = BIT_ULL(0);

trace_kvm_hv_send_ipi(irq.vector, sparse_banks[0]);
trace_kvm_hv_send_ipi(vector, sparse_banks[0]);
} else {
if (unlikely(kvm_read_guest(kvm, ingpa, &send_ipi_ex,
sizeof(send_ipi_ex))))
Expand All @@ -1446,7 +1443,7 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *current_vcpu, u64 ingpa, u64 outgpa,
send_ipi_ex.vp_set.format,
send_ipi_ex.vp_set.valid_bank_mask);

irq.vector = send_ipi_ex.vector;
vector = send_ipi_ex.vector;
valid_bank_mask = send_ipi_ex.vp_set.valid_bank_mask;
sparse_banks_len = bitmap_weight(&valid_bank_mask, 64) *
sizeof(sparse_banks[0]);
Expand All @@ -1465,42 +1462,14 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *current_vcpu, u64 ingpa, u64 outgpa,
return HV_STATUS_INVALID_HYPERCALL_INPUT;
}

if ((irq.vector < HV_IPI_LOW_VECTOR) ||
(irq.vector > HV_IPI_HIGH_VECTOR))
if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR))
return HV_STATUS_INVALID_HYPERCALL_INPUT;

if (all_cpus || atomic_read(&hv->num_mismatched_vp_indexes)) {
kvm_for_each_vcpu(i, vcpu, kvm) {
if (all_cpus || hv_vcpu_in_sparse_set(
&vcpu->arch.hyperv, sparse_banks,
valid_bank_mask)) {
/* We fail only when APIC is disabled */
kvm_apic_set_irq(vcpu, &irq, NULL);
}
}
goto ret_success;
}
vcpu_mask = all_cpus ? NULL :
sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask,
vp_bitmap, vcpu_bitmap);

/*
* 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, 64) {
for_each_set_bit(i, (unsigned long *)&sparse_banks[sbank], 64) {
u32 vp_index = bank * 64 + i;
struct kvm_vcpu *vcpu =
get_vcpu_by_vpidx(kvm, vp_index);

/* Unknown vCPU specified */
if (!vcpu)
continue;

/* We fail only when APIC is disabled */
kvm_apic_set_irq(vcpu, &irq, NULL);
}
sbank++;
}
kvm_send_ipi_to_many(kvm, vector, vcpu_mask);

ret_success:
return HV_STATUS_SUCCESS;
Expand Down

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