From 81f982e5cdc741ea15b8d143cf5f1ee7831920ee Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 31 Dec 2020 11:18:03 +0000
Subject: [PATCH] FROMGIT: KVM: arm64: Fix AArch32 PMUv3 capping

We shouldn't expose *any* PMU capability when no PMU has been
configured for this VM.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
(cherry picked from commit cb95914685ca6514da9a1592b19255fe679557eb
 git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git next)
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: I59a410fc2390f407ff8dd5ecf6883e0a4428cb9f
Bug: 178098380
Test: atest VirtualizationHostTestCases on an EL2-enabled device
---
 arch/arm64/kvm/sys_regs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 2bf56cf1c777..724d8a9c4a9a 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1056,8 +1056,8 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
 	} else if (id == SYS_ID_DFR0_EL1) {
 		/* Limit guests to PMUv3 for ARMv8.1 */
 		val = cpuid_feature_cap_perfmon_field(val,
-						ID_DFR0_PERFMON_SHIFT,
-						ID_DFR0_PERFMON_8_1);
+						      ID_DFR0_PERFMON_SHIFT,
+						      kvm_vcpu_has_pmu(vcpu) ? ID_DFR0_PERFMON_8_1 : 0);
 	}
 
 	return val;