linux-kernel - [PATCH v2 09/12] KVM: x86/pmu: Replace pmc_perf_hw_id() with perf_get_hw_event

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Date:   Wed,  2 Mar 2022 19:13:31 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Jim Mattson <jmattson@...gle.com>, kvm@...r.kernel.org,
        Sean Christopherson <seanjc@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Joerg Roedel <joro@...tes.org>, linux-kernel@...r.kernel.org,
        Like Xu <likexu@...cent.com>
Subject: [PATCH v2 09/12] KVM: x86/pmu: Replace pmc_perf_hw_id() with perf_get_hw_event_config()

From: Like Xu <likexu@...cent.com>

With the help of perf_get_hw_event_config(), KVM could query the correct
EVENTSEL_{EVENT, UMASK} pair of a kernel-generic hw event directly from
the different *_perfmon_event_map[] by the kernel's pre-defined perf_hw_id.

Also extend the bit range of the comparison field to
AMD64_RAW_EVENT_MASK_NB to prevent AMD from
defining EventSelect[11:8] into perfmon_event_map[] one day.

Signed-off-by: Like Xu <likexu@...cent.com>
---
 arch/x86/kvm/pmu.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 00e1660c10ca..9fb7d29e5fdd 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -472,13 +472,8 @@ static void kvm_pmu_incr_counter(struct kvm_pmc *pmc)
 static inline bool eventsel_match_perf_hw_id(struct kvm_pmc *pmc,
 	unsigned int perf_hw_id)
 {
-	u64 old_eventsel = pmc->eventsel;
-	unsigned int config;
-
-	pmc->eventsel &= (ARCH_PERFMON_EVENTSEL_EVENT | ARCH_PERFMON_EVENTSEL_UMASK);
-	config = kvm_x86_ops.pmu_ops->pmc_perf_hw_id(pmc);
-	pmc->eventsel = old_eventsel;
-	return config == perf_hw_id;
+	return !((pmc->eventsel ^ perf_get_hw_event_config(perf_hw_id)) &
+		AMD64_RAW_EVENT_MASK_NB);
 }
 
 static inline bool cpl_is_matched(struct kvm_pmc *pmc)
-- 
2.35.1