linux-kernel - [PATCH v3 11/17] KVM: x86/pmu: Adjust precise_ip to emulate Ice Lake guest PDIR counter

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Date:   Mon,  4 Jan 2021 21:15:36 +0800
From:   Like Xu <like.xu@...ux.intel.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Paolo Bonzini <pbonzini@...hat.com>, eranian@...gle.com,
        kvm@...r.kernel.org
Cc:     Ingo Molnar <mingo@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Andi Kleen <andi@...stfloor.org>,
        Kan Liang <kan.liang@...ux.intel.com>, wei.w.wang@...el.com,
        luwei.kang@...el.com, linux-kernel@...r.kernel.org
Subject: [PATCH v3 11/17] KVM: x86/pmu: Adjust precise_ip to emulate Ice Lake guest PDIR counter

The PEBS-PDIR facility on Ice Lake server is supported on IA31_FIXED0 only.
If the guest configures counter 32 and PEBS is enabled, the PEBS-PDIR
facility is supposed to be used, in which case KVM adjusts attr.precise_ip
to 3 and request host perf to assign the exactly requested counter or fail.

The cpu model check is also required since some platforms may place the
PEBS-PDIR facility in another counter index.

Signed-off-by: Like Xu <like.xu@...ux.intel.com>
---
 arch/x86/kvm/pmu.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 2e81c50323e2..67c20ab81991 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -144,6 +144,8 @@ static void pmc_reprogram_counter(struct kvm_pmc *pmc, u32 type,
 		 * in the PEBS record is calibrated on the guest side.
 		 */
 		attr.precise_ip = 1;
+		if (x86_match_cpu(vmx_icl_pebs_cpu) && pmc->idx == 32)
+			attr.precise_ip = 3;
 	}
 
 	event = perf_event_create_kernel_counter(&attr, -1, current,
-- 
2.29.2