* [PATCH v2 1/4] KVM: x86/pmu: Setup pmc->eventsel for fixed PMCs
2021-11-19 6:48 [PATCH v2 0/4] KVM: x86/pmu: Refactoring code by reusing pmc->eventsel for fixed_counters Like Xu
@ 2021-11-19 6:48 ` Like Xu
2021-11-19 6:48 ` [PATCH v2 2/4] KVM: x86/pmu: Refactoring find_arch_event() to pmc_perf_hw_id() Like Xu
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Like Xu @ 2021-11-19 6:48 UTC (permalink / raw)
To: Paolo Bonzini
Cc: Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
Joerg Roedel, kvm, linux-kernel
From: Like Xu <likexu@tencent.com>
The current pmc->eventsel for fixed counter is underutilised. The
pmc->eventsel can be setup for all known available fixed counters
since we have mapping between fixed pmc index and
the intel_arch_events array.
Either gp or fixed counter, it will simplify the later checks for
consistency between eventsel and perf_hw_id.
Signed-off-by: Like Xu <likexu@tencent.com>
---
arch/x86/kvm/vmx/pmu_intel.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 1b7456b2177b..b7ab5fd03681 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -459,6 +459,21 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
return 1;
}
+static void setup_fixed_pmc_eventsel(struct kvm_pmu *pmu)
+{
+ size_t size = ARRAY_SIZE(fixed_pmc_events);
+ struct kvm_pmc *pmc;
+ u32 event;
+ int i;
+
+ for (i = 0; i < pmu->nr_arch_fixed_counters; i++) {
+ pmc = &pmu->fixed_counters[i];
+ event = fixed_pmc_events[array_index_nospec(i, size)];
+ pmc->eventsel = (intel_arch_events[event].unit_mask << 8) |
+ intel_arch_events[event].eventsel;
+ }
+}
+
static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
{
struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
@@ -506,6 +521,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
edx.split.bit_width_fixed, x86_pmu.bit_width_fixed);
pmu->counter_bitmask[KVM_PMC_FIXED] =
((u64)1 << edx.split.bit_width_fixed) - 1;
+ setup_fixed_pmc_eventsel(pmu);
}
pmu->global_ctrl = ((1ull << pmu->nr_arch_gp_counters) - 1) |
--
2.33.1
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH v2 2/4] KVM: x86/pmu: Refactoring find_arch_event() to pmc_perf_hw_id()
2021-11-19 6:48 [PATCH v2 0/4] KVM: x86/pmu: Refactoring code by reusing pmc->eventsel for fixed_counters Like Xu
2021-11-19 6:48 ` [PATCH v2 1/4] KVM: x86/pmu: Setup pmc->eventsel for fixed PMCs Like Xu
@ 2021-11-19 6:48 ` Like Xu
2021-11-19 6:48 ` [PATCH v2 3/4] KVM: x86/pmu: Reuse pmc_perf_hw_id() and drop find_fixed_event() Like Xu
2021-11-19 6:48 ` [PATCH v2 4/4] KVM: x86/pmu: Add pmc->intr to refactor kvm_perf_overflow{_intr}() Like Xu
3 siblings, 0 replies; 5+ messages in thread
From: Like Xu @ 2021-11-19 6:48 UTC (permalink / raw)
To: Paolo Bonzini
Cc: Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
Joerg Roedel, kvm, linux-kernel
From: Like Xu <likexu@tencent.com>
The find_arch_event() returns a "unsigned int" value,
which is used by the pmc_reprogram_counter() to
program a PERF_TYPE_HARDWARE type perf_event.
The returned value is actually the kernel defined gernic
perf_hw_id, let's rename it to pmc_perf_hw_id() with simpler
incoming parameters for better self-explanation.
Signed-off-by: Like Xu <likexu@tencent.com>
---
arch/x86/kvm/pmu.c | 8 +-------
arch/x86/kvm/pmu.h | 3 +--
arch/x86/kvm/svm/pmu.c | 8 ++++----
arch/x86/kvm/vmx/pmu_intel.c | 9 +++++----
4 files changed, 11 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 09873f6488f7..3b3ccf5b1106 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -174,7 +174,6 @@ static bool pmc_resume_counter(struct kvm_pmc *pmc)
void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
{
unsigned config, type = PERF_TYPE_RAW;
- u8 event_select, unit_mask;
struct kvm *kvm = pmc->vcpu->kvm;
struct kvm_pmu_event_filter *filter;
int i;
@@ -206,17 +205,12 @@ void reprogram_gp_counter(struct kvm_pmc *pmc, u64 eventsel)
if (!allow_event)
return;
- event_select = eventsel & ARCH_PERFMON_EVENTSEL_EVENT;
- unit_mask = (eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
-
if (!(eventsel & (ARCH_PERFMON_EVENTSEL_EDGE |
ARCH_PERFMON_EVENTSEL_INV |
ARCH_PERFMON_EVENTSEL_CMASK |
HSW_IN_TX |
HSW_IN_TX_CHECKPOINTED))) {
- config = kvm_x86_ops.pmu_ops->find_arch_event(pmc_to_pmu(pmc),
- event_select,
- unit_mask);
+ config = kvm_x86_ops.pmu_ops->pmc_perf_hw_id(pmc);
if (config != PERF_COUNT_HW_MAX)
type = PERF_TYPE_HARDWARE;
}
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index 59d6b76203d5..dd7dbb1c5048 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -24,8 +24,7 @@ struct kvm_event_hw_type_mapping {
};
struct kvm_pmu_ops {
- unsigned (*find_arch_event)(struct kvm_pmu *pmu, u8 event_select,
- u8 unit_mask);
+ unsigned int (*pmc_perf_hw_id)(struct kvm_pmc *pmc);
unsigned (*find_fixed_event)(int idx);
bool (*pmc_is_enabled)(struct kvm_pmc *pmc);
struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx);
diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index 871c426ec389..3c00a34457d7 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -134,10 +134,10 @@ static inline struct kvm_pmc *get_gp_pmc_amd(struct kvm_pmu *pmu, u32 msr,
return &pmu->gp_counters[msr_to_index(msr)];
}
-static unsigned amd_find_arch_event(struct kvm_pmu *pmu,
- u8 event_select,
- u8 unit_mask)
+static unsigned int amd_pmc_perf_hw_id(struct kvm_pmc *pmc)
{
+ u8 event_select = pmc->eventsel & ARCH_PERFMON_EVENTSEL_EVENT;
+ u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
int i;
for (i = 0; i < ARRAY_SIZE(amd_event_mapping); i++)
@@ -319,7 +319,7 @@ static void amd_pmu_reset(struct kvm_vcpu *vcpu)
}
struct kvm_pmu_ops amd_pmu_ops = {
- .find_arch_event = amd_find_arch_event,
+ .pmc_perf_hw_id = amd_pmc_perf_hw_id,
.find_fixed_event = amd_find_fixed_event,
.pmc_is_enabled = amd_pmc_is_enabled,
.pmc_idx_to_pmc = amd_pmc_idx_to_pmc,
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index b7ab5fd03681..67a0188ecdc5 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -68,10 +68,11 @@ static void global_ctrl_changed(struct kvm_pmu *pmu, u64 data)
reprogram_counter(pmu, bit);
}
-static unsigned intel_find_arch_event(struct kvm_pmu *pmu,
- u8 event_select,
- u8 unit_mask)
+static unsigned int intel_pmc_perf_hw_id(struct kvm_pmc *pmc)
{
+ struct kvm_pmu *pmu = pmc_to_pmu(pmc);
+ u8 event_select = pmc->eventsel & ARCH_PERFMON_EVENTSEL_EVENT;
+ u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
int i;
for (i = 0; i < ARRAY_SIZE(intel_arch_events); i++)
@@ -719,7 +720,7 @@ static void intel_pmu_cleanup(struct kvm_vcpu *vcpu)
}
struct kvm_pmu_ops intel_pmu_ops = {
- .find_arch_event = intel_find_arch_event,
+ .pmc_perf_hw_id = intel_pmc_perf_hw_id,
.find_fixed_event = intel_find_fixed_event,
.pmc_is_enabled = intel_pmc_is_enabled,
.pmc_idx_to_pmc = intel_pmc_idx_to_pmc,
--
2.33.1
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH v2 3/4] KVM: x86/pmu: Reuse pmc_perf_hw_id() and drop find_fixed_event()
2021-11-19 6:48 [PATCH v2 0/4] KVM: x86/pmu: Refactoring code by reusing pmc->eventsel for fixed_counters Like Xu
2021-11-19 6:48 ` [PATCH v2 1/4] KVM: x86/pmu: Setup pmc->eventsel for fixed PMCs Like Xu
2021-11-19 6:48 ` [PATCH v2 2/4] KVM: x86/pmu: Refactoring find_arch_event() to pmc_perf_hw_id() Like Xu
@ 2021-11-19 6:48 ` Like Xu
2021-11-19 6:48 ` [PATCH v2 4/4] KVM: x86/pmu: Add pmc->intr to refactor kvm_perf_overflow{_intr}() Like Xu
3 siblings, 0 replies; 5+ messages in thread
From: Like Xu @ 2021-11-19 6:48 UTC (permalink / raw)
To: Paolo Bonzini
Cc: Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
Joerg Roedel, kvm, linux-kernel
From: Like Xu <likexu@tencent.com>
Since we set the same semantic event value for the fixed counter in
pmc->eventsel, returning the perf_hw_id for the fixed counter via
find_fixed_event() can be painlessly replaced by pmc_perf_hw_id()
with the help of pmc_is_fixed() check.
Signed-off-by: Like Xu <likexu@tencent.com>
---
arch/x86/kvm/pmu.c | 2 +-
arch/x86/kvm/pmu.h | 1 -
arch/x86/kvm/svm/pmu.c | 11 ++++-------
arch/x86/kvm/vmx/pmu_intel.c | 29 ++++++++++++++++-------------
4 files changed, 21 insertions(+), 22 deletions(-)
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 3b3ccf5b1106..b7a1ae28ab87 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -262,7 +262,7 @@ 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->find_fixed_event(idx),
+ kvm_x86_ops.pmu_ops->pmc_perf_hw_id(pmc),
!(en_field & 0x2), /* exclude user */
!(en_field & 0x1), /* exclude kernel */
pmi, false, false);
diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index dd7dbb1c5048..c91d9725aafd 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -25,7 +25,6 @@ struct kvm_event_hw_type_mapping {
struct kvm_pmu_ops {
unsigned int (*pmc_perf_hw_id)(struct kvm_pmc *pmc);
- unsigned (*find_fixed_event)(int idx);
bool (*pmc_is_enabled)(struct kvm_pmc *pmc);
struct kvm_pmc *(*pmc_idx_to_pmc)(struct kvm_pmu *pmu, int pmc_idx);
struct kvm_pmc *(*rdpmc_ecx_to_pmc)(struct kvm_vcpu *vcpu,
diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index 3c00a34457d7..da8aa1e5bff0 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -140,6 +140,10 @@ static unsigned int amd_pmc_perf_hw_id(struct kvm_pmc *pmc)
u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
int i;
+ /* return PERF_COUNT_HW_MAX as AMD doesn't have fixed events */
+ if (WARN_ON(pmc_is_fixed(pmc)))
+ return PERF_COUNT_HW_MAX;
+
for (i = 0; i < ARRAY_SIZE(amd_event_mapping); i++)
if (amd_event_mapping[i].eventsel == event_select
&& amd_event_mapping[i].unit_mask == unit_mask)
@@ -151,12 +155,6 @@ static unsigned int amd_pmc_perf_hw_id(struct kvm_pmc *pmc)
return amd_event_mapping[i].event_type;
}
-/* return PERF_COUNT_HW_MAX as AMD doesn't have fixed events */
-static unsigned amd_find_fixed_event(int idx)
-{
- return PERF_COUNT_HW_MAX;
-}
-
/* check if a PMC is enabled by comparing it against global_ctrl bits. Because
* AMD CPU doesn't have global_ctrl MSR, all PMCs are enabled (return TRUE).
*/
@@ -320,7 +318,6 @@ static void amd_pmu_reset(struct kvm_vcpu *vcpu)
struct kvm_pmu_ops amd_pmu_ops = {
.pmc_perf_hw_id = amd_pmc_perf_hw_id,
- .find_fixed_event = amd_find_fixed_event,
.pmc_is_enabled = amd_pmc_is_enabled,
.pmc_idx_to_pmc = amd_pmc_idx_to_pmc,
.rdpmc_ecx_to_pmc = amd_rdpmc_ecx_to_pmc,
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 67a0188ecdc5..72db4ffb7eb2 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -68,6 +68,19 @@ static void global_ctrl_changed(struct kvm_pmu *pmu, u64 data)
reprogram_counter(pmu, bit);
}
+static inline unsigned int intel_find_fixed_event(int idx)
+{
+ u32 event;
+ size_t size = ARRAY_SIZE(fixed_pmc_events);
+
+ if (idx >= size)
+ return PERF_COUNT_HW_MAX;
+
+ event = fixed_pmc_events[array_index_nospec(idx, size)];
+ return intel_arch_events[event].event_type;
+}
+
+
static unsigned int intel_pmc_perf_hw_id(struct kvm_pmc *pmc)
{
struct kvm_pmu *pmu = pmc_to_pmu(pmc);
@@ -75,6 +88,9 @@ static unsigned int intel_pmc_perf_hw_id(struct kvm_pmc *pmc)
u8 unit_mask = (pmc->eventsel & ARCH_PERFMON_EVENTSEL_UMASK) >> 8;
int i;
+ if (pmc_is_fixed(pmc))
+ return intel_find_fixed_event(pmc->idx - INTEL_PMC_IDX_FIXED);
+
for (i = 0; i < ARRAY_SIZE(intel_arch_events); i++)
if (intel_arch_events[i].eventsel == event_select
&& intel_arch_events[i].unit_mask == unit_mask
@@ -87,18 +103,6 @@ static unsigned int intel_pmc_perf_hw_id(struct kvm_pmc *pmc)
return intel_arch_events[i].event_type;
}
-static unsigned intel_find_fixed_event(int idx)
-{
- u32 event;
- size_t size = ARRAY_SIZE(fixed_pmc_events);
-
- if (idx >= size)
- return PERF_COUNT_HW_MAX;
-
- event = fixed_pmc_events[array_index_nospec(idx, size)];
- return intel_arch_events[event].event_type;
-}
-
/* check if a PMC is enabled by comparing it with globl_ctrl bits. */
static bool intel_pmc_is_enabled(struct kvm_pmc *pmc)
{
@@ -721,7 +725,6 @@ static void intel_pmu_cleanup(struct kvm_vcpu *vcpu)
struct kvm_pmu_ops intel_pmu_ops = {
.pmc_perf_hw_id = intel_pmc_perf_hw_id,
- .find_fixed_event = intel_find_fixed_event,
.pmc_is_enabled = intel_pmc_is_enabled,
.pmc_idx_to_pmc = intel_pmc_idx_to_pmc,
.rdpmc_ecx_to_pmc = intel_rdpmc_ecx_to_pmc,
--
2.33.1
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH v2 4/4] KVM: x86/pmu: Add pmc->intr to refactor kvm_perf_overflow{_intr}()
2021-11-19 6:48 [PATCH v2 0/4] KVM: x86/pmu: Refactoring code by reusing pmc->eventsel for fixed_counters Like Xu
` (2 preceding siblings ...)
2021-11-19 6:48 ` [PATCH v2 3/4] KVM: x86/pmu: Reuse pmc_perf_hw_id() and drop find_fixed_event() Like Xu
@ 2021-11-19 6:48 ` Like Xu
3 siblings, 0 replies; 5+ messages in thread
From: Like Xu @ 2021-11-19 6:48 UTC (permalink / raw)
To: Paolo Bonzini
Cc: Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li, Jim Mattson,
Joerg Roedel, kvm, linux-kernel
From: Like Xu <likexu@tencent.com>
Depending on whether intr should be triggered or not, KVM registers
two different event overflow callbacks in the perf_event context.
The code skeleton of these two functions is very similar, so
the pmc->intr can be stored into pmc from pmc_reprogram_counter()
which provides smaller instructions footprint against the
u-architecture branch predictor.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Like Xu <likexu@tencent.com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/pmu.c | 48 ++++++++++++++-------------------
2 files changed, 21 insertions(+), 28 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1fcb345bc107..9fa63499e77e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -496,6 +496,7 @@ struct kvm_pmc {
*/
u64 current_config;
bool is_paused;
+ bool intr;
};
struct kvm_pmu {
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index b7a1ae28ab87..9b52f18f56e0 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -62,36 +62,28 @@ static void kvm_perf_overflow(struct perf_event *perf_event,
struct kvm_pmc *pmc = perf_event->overflow_handler_context;
struct kvm_pmu *pmu = pmc_to_pmu(pmc);
- if (!test_and_set_bit(pmc->idx, pmu->reprogram_pmi)) {
- __set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
- kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
- }
-}
+ /* Ignore counters that have been reprogrammed already. */
+ if (test_and_set_bit(pmc->idx, pmu->reprogram_pmi))
+ return;
-static void kvm_perf_overflow_intr(struct perf_event *perf_event,
- struct perf_sample_data *data,
- struct pt_regs *regs)
-{
- struct kvm_pmc *pmc = perf_event->overflow_handler_context;
- struct kvm_pmu *pmu = pmc_to_pmu(pmc);
+ __set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
+ kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
- if (!test_and_set_bit(pmc->idx, pmu->reprogram_pmi)) {
- __set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
- kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
+ if (!pmc->intr)
+ return;
- /*
- * Inject PMI. If vcpu was in a guest mode during NMI PMI
- * can be ejected on a guest mode re-entry. Otherwise we can't
- * be sure that vcpu wasn't executing hlt instruction at the
- * time of vmexit and is not going to re-enter guest mode until
- * woken up. So we should wake it, but this is impossible from
- * NMI context. Do it from irq work instead.
- */
- if (!kvm_is_in_guest())
- irq_work_queue(&pmc_to_pmu(pmc)->irq_work);
- else
- kvm_make_request(KVM_REQ_PMI, pmc->vcpu);
- }
+ /*
+ * Inject PMI. If vcpu was in a guest mode during NMI PMI
+ * can be ejected on a guest mode re-entry. Otherwise we can't
+ * be sure that vcpu wasn't executing hlt instruction at the
+ * time of vmexit and is not going to re-enter guest mode until
+ * woken up. So we should wake it, but this is impossible from
+ * NMI context. Do it from irq work instead.
+ */
+ if (!kvm_is_in_guest())
+ irq_work_queue(&pmc_to_pmu(pmc)->irq_work);
+ else
+ kvm_make_request(KVM_REQ_PMI, pmc->vcpu);
}
static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type,
@@ -126,7 +118,6 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type,
}
event = perf_event_create_kernel_counter(&attr, -1, current,
- intr ? kvm_perf_overflow_intr :
kvm_perf_overflow, pmc);
if (IS_ERR(event)) {
pr_debug_ratelimited("kvm_pmu: event creation failed %ld for pmc->idx = %d\n",
@@ -138,6 +129,7 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type,
pmc_to_pmu(pmc)->event_count++;
clear_bit(pmc->idx, pmc_to_pmu(pmc)->reprogram_pmi);
pmc->is_paused = false;
+ pmc->intr = intr;
}
static void pmc_pause_counter(struct kvm_pmc *pmc)
--
2.33.1
^ permalink raw reply [flat|nested] 5+ messages in thread