[PATCH v3 2/4] KVM: x86: Copy kvm_pmu_ops by value to eliminate layer of indirection

From: Like Xu
Date: Mon Mar 07 2022 - 06:59:44 EST

From: Like Xu <likexu@xxxxxxxxxxx>

Replace the kvm_pmu_ops pointer in common x86 with an instance of the
struct to save one pointer dereference when invoking functions. Copy the
struct by value to set the ops during kvm_init().

Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
---
arch/x86/kvm/pmu.c | 44 +++++++++++++++++++++++---------------------
arch/x86/kvm/pmu.h | 4 +++-
arch/x86/kvm/x86.c | 1 +
3 files changed, 27 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index b1a02993782b..771edc4f4494 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -49,6 +49,8 @@
* * AMD: [0 .. AMD64_NUM_COUNTERS-1] <=> gp counters
*/

+struct kvm_pmu_ops kvm_pmu_ops __read_mostly;
+
static void kvm_pmi_trigger_fn(struct irq_work *irq_work)
{
struct kvm_pmu *pmu = container_of(irq_work, struct kvm_pmu, irq_work);
@@ -215,7 +217,7 @@ void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
ARCH_PERFMON_EVENTSEL_CMASK |
HSW_IN_TX |
HSW_IN_TX_CHECKPOINTED))) {
- config = kvm_x86_ops.pmu_ops->pmc_perf_hw_id(pmc);
+ config = kvm_pmu_ops.pmc_perf_hw_id(pmc);
if (config != PERF_COUNT_HW_MAX)
type = PERF_TYPE_HARDWARE;
}
@@ -267,7 +269,7 @@ void reprogram_fixed_counter(struct kvm_pmc *pmc, u8 ctrl, int idx)

pmc->current_config = (u64)ctrl;
pmc_reprogram_counter(pmc, PERF_TYPE_HARDWARE,
- kvm_x86_ops.pmu_ops->pmc_perf_hw_id(pmc),
+ kvm_pmu_ops.pmc_perf_hw_id(pmc),
!(en_field & 0x2), /* exclude user */
!(en_field & 0x1), /* exclude kernel */
pmi, false, false);
@@ -276,7 +278,7 @@ EXPORT_SYMBOL_GPL(reprogram_fixed_counter);

void reprogram_counter(struct kvm_pmu *pmu, int pmc_idx)
{
- struct kvm_pmc *pmc = kvm_x86_ops.pmu_ops->pmc_idx_to_pmc(pmu, pmc_idx);
+ struct kvm_pmc *pmc = kvm_pmu_ops.pmc_idx_to_pmc(pmu, pmc_idx);

if (!pmc)
return;
@@ -298,7 +300,7 @@ void kvm_pmu_handle_event(struct kvm_vcpu *vcpu)
int bit;

for_each_set_bit(bit, pmu->reprogram_pmi, X86_PMC_IDX_MAX) {
- struct kvm_pmc *pmc = kvm_x86_ops.pmu_ops->pmc_idx_to_pmc(pmu, bit);
+ struct kvm_pmc *pmc = kvm_pmu_ops.pmc_idx_to_pmc(pmu, bit);

if (unlikely(!pmc || !pmc->perf_event)) {
clear_bit(bit, pmu->reprogram_pmi);
@@ -320,7 +322,7 @@ void kvm_pmu_handle_event(struct kvm_vcpu *vcpu)
/* check if idx is a valid index to access PMU */
bool kvm_pmu_is_valid_rdpmc_ecx(struct kvm_vcpu *vcpu, unsigned int idx)
{
- return kvm_x86_ops.pmu_ops->is_valid_rdpmc_ecx(vcpu, idx);
+ return kvm_pmu_ops.is_valid_rdpmc_ecx(vcpu, idx);
}

bool is_vmware_backdoor_pmc(u32 pmc_idx)
@@ -370,7 +372,7 @@ int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
if (is_vmware_backdoor_pmc(idx))
return kvm_pmu_rdpmc_vmware(vcpu, idx, data);

- pmc = kvm_x86_ops.pmu_ops->rdpmc_ecx_to_pmc(vcpu, idx, &mask);
+ pmc = kvm_pmu_ops.rdpmc_ecx_to_pmc(vcpu, idx, &mask);
if (!pmc)
return 1;

@@ -386,22 +388,22 @@ int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
void kvm_pmu_deliver_pmi(struct kvm_vcpu *vcpu)
{
if (lapic_in_kernel(vcpu)) {
- if (kvm_x86_ops.pmu_ops->deliver_pmi)
- kvm_x86_ops.pmu_ops->deliver_pmi(vcpu);
+ if (kvm_pmu_ops.deliver_pmi)
+ kvm_pmu_ops.deliver_pmi(vcpu);
kvm_apic_local_deliver(vcpu->arch.apic, APIC_LVTPC);
}
}

bool kvm_pmu_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
{
- return kvm_x86_ops.pmu_ops->msr_idx_to_pmc(vcpu, msr) ||
- kvm_x86_ops.pmu_ops->is_valid_msr(vcpu, msr);
+ return kvm_pmu_ops.msr_idx_to_pmc(vcpu, msr) ||
+ kvm_pmu_ops.is_valid_msr(vcpu, msr);
}

static void kvm_pmu_mark_pmc_in_use(struct kvm_vcpu *vcpu, u32 msr)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
- struct kvm_pmc *pmc = kvm_x86_ops.pmu_ops->msr_idx_to_pmc(vcpu, msr);
+ struct kvm_pmc *pmc = kvm_pmu_ops.msr_idx_to_pmc(vcpu, msr);

if (pmc)
__set_bit(pmc->idx, pmu->pmc_in_use);
@@ -409,13 +411,13 @@ static void kvm_pmu_mark_pmc_in_use(struct kvm_vcpu *vcpu, u32 msr)

int kvm_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
- return kvm_x86_ops.pmu_ops->get_msr(vcpu, msr_info);
+ return kvm_pmu_ops.get_msr(vcpu, msr_info);
}

int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
kvm_pmu_mark_pmc_in_use(vcpu, msr_info->index);
- return kvm_x86_ops.pmu_ops->set_msr(vcpu, msr_info);
+ return kvm_pmu_ops.set_msr(vcpu, msr_info);
}

/* refresh PMU settings. This function generally is called when underlying
@@ -424,7 +426,7 @@ int kvm_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
*/
void kvm_pmu_refresh(struct kvm_vcpu *vcpu)
{
- kvm_x86_ops.pmu_ops->refresh(vcpu);
+ kvm_pmu_ops.refresh(vcpu);
}

void kvm_pmu_reset(struct kvm_vcpu *vcpu)
@@ -432,7 +434,7 @@ void kvm_pmu_reset(struct kvm_vcpu *vcpu)
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);

irq_work_sync(&pmu->irq_work);
- kvm_x86_ops.pmu_ops->reset(vcpu);
+ kvm_pmu_ops.reset(vcpu);
}

void kvm_pmu_init(struct kvm_vcpu *vcpu)
@@ -440,7 +442,7 @@ void kvm_pmu_init(struct kvm_vcpu *vcpu)
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);

memset(pmu, 0, sizeof(*pmu));
- kvm_x86_ops.pmu_ops->init(vcpu);
+ kvm_pmu_ops.init(vcpu);
init_irq_work(&pmu->irq_work, kvm_pmi_trigger_fn);
pmu->event_count = 0;
pmu->need_cleanup = false;
@@ -472,14 +474,14 @@ void kvm_pmu_cleanup(struct kvm_vcpu *vcpu)
pmu->pmc_in_use, X86_PMC_IDX_MAX);

for_each_set_bit(i, bitmask, X86_PMC_IDX_MAX) {
- pmc = kvm_x86_ops.pmu_ops->pmc_idx_to_pmc(pmu, i);
+ pmc = kvm_pmu_ops.pmc_idx_to_pmc(pmu, i);

if (pmc && pmc->perf_event && !pmc_speculative_in_use(pmc))
pmc_stop_counter(pmc);
}

- if (kvm_x86_ops.pmu_ops->cleanup)
- kvm_x86_ops.pmu_ops->cleanup(vcpu);
+ if (kvm_pmu_ops.cleanup)
+ kvm_pmu_ops.cleanup(vcpu);

bitmap_zero(pmu->pmc_in_use, X86_PMC_IDX_MAX);
}
@@ -509,7 +511,7 @@ static inline bool eventsel_match_perf_hw_id(struct kvm_pmc *pmc,
unsigned int config;

pmc->eventsel &= (ARCH_PERFMON_EVENTSEL_EVENT | ARCH_PERFMON_EVENTSEL_UMASK);
- config = kvm_x86_ops.pmu_ops->pmc_perf_hw_id(pmc);
+ config = kvm_pmu_ops.pmc_perf_hw_id(pmc);
pmc->eventsel = old_eventsel;
return config == perf_hw_id;
}
@@ -537,7 +539,7 @@ void kvm_pmu_trigger_event(struct kvm_vcpu *vcpu, u64 perf_hw_id)
int i;

for_each_set_bit(i, pmu->all_valid_pmc_idx, X86_PMC_IDX_MAX) {
- pmc = kvm_x86_ops.pmu_ops->pmc_idx_to_pmc(pmu, i);
+ pmc = kvm_pmu_ops.pmc_idx_to_pmc(pmu, i);

if (!pmc || !pmc_is_enabled(pmc) || !pmc_speculative_in_use(pmc))
continue;
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 7a7b8d5b775e..7032d3ebf8f4 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -17,6 +17,8 @@

#define MAX_FIXED_COUNTERS 3

+extern struct kvm_pmu_ops kvm_pmu_ops;
+
struct kvm_event_hw_type_mapping {
u8 eventsel;
u8 unit_mask;
@@ -90,7 +92,7 @@ static inline bool pmc_is_fixed(struct kvm_pmc *pmc)

static inline bool pmc_is_enabled(struct kvm_pmc *pmc)
{
- return kvm_x86_ops.pmu_ops->pmc_is_enabled(pmc);
+ return kvm_pmu_ops.pmc_is_enabled(pmc);
}

static inline bool kvm_valid_perf_global_ctrl(struct kvm_pmu *pmu,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7b4e84d80b57..dcaeedeef675 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11536,6 +11536,7 @@ int kvm_arch_hardware_setup(void *opaque)
return r;

memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops));
+ memcpy(&kvm_pmu_ops, kvm_x86_ops.pmu_ops, sizeof(kvm_pmu_ops));
kvm_ops_static_call_update();

kvm_register_perf_callbacks(ops->handle_intel_pt_intr);
--
2.35.1