linux-kernel - [PATCH 2/2] KVM: vmx/pmu: Add support for selected fixed vPMU enablement for PMU v5

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20230427095333.35038-3-abusse@amazon.com>
Date:   Thu, 27 Apr 2023 09:53:33 +0000
From:   Anselm Busse <abusse@...zon.com>
To:     unlisted-recipients:; (no To-header on input)
CC:     <dwmw@...zon.co.uk>, <hborghor@...zon.de>, <sironi@...zon.de>,
        "Anselm Busse" <abusse@...zon.com>,
        Sean Christopherson <seanjc@...gle.com>,
        "Paolo Bonzini" <pbonzini@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Ingo Molnar" <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>, <kvm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] KVM: vmx/pmu: Add support for selected fixed vPMU enablement for PMU v5

This commits adds virtualization support to enable slected fixed
function PMCs for Intel PMU v5 based on CPUID.0AH.ECX.

Starting with v5, the Intel PMU allows to indicate the available fixed
function PMCs not only through CPUID.0AH.EDX[4:0] but also through a
bit mask in CPUID.0AH.ECX. According to the SDM the OS can consider a
fix function PMC i supported for:

CPUID.0AH.ECX[i] || (CPUID.0AH.EDX[4:0] > i)

This behavior is already supported by the Intel PMU driver. However, KVM
support is missing. Therefore, this commit extends the KVM
implementation by also taking the values in CPUID.0AH.ECX into account
when setting the bitmap of enabled fixed function PMCs.

Signed-off-by: Anselm Busse <abusse@...zon.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 55ff06a9df47..d1fd3472bfd4 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -562,6 +562,13 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
 						  kvm_pmu_cap.bit_width_fixed);
 		pmu->counter_bitmask[KVM_PMC_FIXED] =
 			((u64)1 << edx.split.bit_width_fixed) - 1;
+
+		if (pmu->version >= 5)
+			bitmap_or(pmu->mask_arch_fixed_counters,
+				  pmu->mask_arch_fixed_counters,
+				  (unsigned long *)&entry->ecx,
+				  INTEL_PMC_MAX_FIXED);
+
 		setup_fixed_pmc_eventsel(pmu);
 	}

-- 
2.39.2

Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879