linux-kernel - [PATCH v12 03/17] perf/x86/core: Pass "struct kvm

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Date:   Fri,  4 Mar 2022 17:04:13 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Sean Christopherson <seanjc@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v12 03/17] perf/x86/core: Pass "struct kvm_pmu *" to determine the guest values

From: Like Xu <like.xu@...ux.intel.com>

Splitting the logic for determining the guest values is unnecessarily
confusing, and potentially fragile. Perf should have full knowledge and
control of what values are loaded for the guest.

If we change .guest_get_msrs() to take a struct kvm_pmu pointer, then it
can generate the full set of guest values by grabbing guest ds_area and
pebs_data_cfg. Alternatively, .guest_get_msrs() could take the desired
guest MSR values directly (ds_area and pebs_data_cfg), but kvm_pmu is
vendor agnostic, so we don't see any reason to not just pass the pointer.

Suggested-by: Sean Christopherson <seanjc@...gle.com>
Signed-off-by: Like Xu <like.xu@...ux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/events/core.c            | 4 ++--
 arch/x86/events/intel/core.c      | 4 ++--
 arch/x86/events/perf_event.h      | 2 +-
 arch/x86/include/asm/perf_event.h | 4 ++--
 arch/x86/kvm/vmx/vmx.c            | 3 ++-
 5 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 7e3d0a019444..0ce9493cc110 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -693,9 +693,9 @@ void x86_pmu_disable_all(void)
 	}
 }
 
-struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr)
+struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr, void *data)
 {
-	return static_call(x86_pmu_guest_get_msrs)(nr);
+	return static_call(x86_pmu_guest_get_msrs)(nr, data);
 }
 EXPORT_SYMBOL_GPL(perf_guest_get_msrs);
 
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index da4b77f6c6a4..820f9fb9339b 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3951,7 +3951,7 @@ static int intel_pmu_hw_config(struct perf_event *event)
 	return 0;
 }
 
-static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr)
+static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr, void *data)
 {
 	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 	struct perf_guest_switch_msr *arr = cpuc->guest_switch_msrs;
@@ -3984,7 +3984,7 @@ static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr)
 	return arr;
 }
 
-static struct perf_guest_switch_msr *core_guest_get_msrs(int *nr)
+static struct perf_guest_switch_msr *core_guest_get_msrs(int *nr, void *data)
 {
 	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 	struct perf_guest_switch_msr *arr = cpuc->guest_switch_msrs;
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 0998742760c8..bf23cbe4f6cf 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -900,7 +900,7 @@ struct x86_pmu {
 	/*
 	 * Intel host/guest support (KVM)
 	 */
-	struct perf_guest_switch_msr *(*guest_get_msrs)(int *nr);
+	struct perf_guest_switch_msr *(*guest_get_msrs)(int *nr, void *data);
 
 	/*
 	 * Check period value for PERF_EVENT_IOC_PERIOD ioctl.
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 2c9dce37d095..729658f00ee6 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -492,10 +492,10 @@ static inline void perf_check_microcode(void) { }
 #endif
 
 #if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_INTEL)
-extern struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr);
+extern struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr, void *data);
 extern int x86_perf_get_lbr(struct x86_pmu_lbr *lbr);
 #else
-struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr);
+struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr, void *data);
 static inline int x86_perf_get_lbr(struct x86_pmu_lbr *lbr)
 {
 	return -1;
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index b325f99b2177..8fb29bbfe875 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6710,9 +6710,10 @@ static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx)
 {
 	int i, nr_msrs;
 	struct perf_guest_switch_msr *msrs;
+	struct kvm_pmu *pmu = vcpu_to_pmu(&vmx->vcpu);
 
 	/* Note, nr_msrs may be garbage if perf_guest_get_msrs() returns NULL. */
-	msrs = perf_guest_get_msrs(&nr_msrs);
+	msrs = perf_guest_get_msrs(&nr_msrs, (void *)pmu);
 	if (!msrs)
 		return;
 
-- 
2.35.1