[PATCH v1] KVM: arm64: PMU: Restore the guest's EL0 event counting after migration

From: Reiji Watanabe <reijiw@google.com>
To: Marc Zyngier <maz@kernel.org>,
	Oliver Upton <oliver.upton@linux.dev>,
	kvmarm@lists.linux.dev
Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	 James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	 Zenghui Yu <yuzenghui@huawei.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	 Paolo Bonzini <pbonzini@redhat.com>,
	Ricardo Koller <ricarkol@google.com>,
	 Jing Zhang <jingzhangos@google.com>,
	Raghavendra Rao Anata <rananta@google.com>,
	 Will Deacon <will@kernel.org>,
	Reiji Watanabe <reijiw@google.com>,
	stable@vger.kernel.org
Subject: [PATCH v1] KVM: arm64: PMU: Restore the guest's EL0 event counting after migration
Date: Mon, 27 Mar 2023 20:47:25 -0700	[thread overview]
Message-ID: <20230328034725.2051499-1-reijiw@google.com> (raw)

Currently, with VHE, KVM enables the EL0 event counting for the
guest on vcpu_load() or KVM enables it as a part of the PMU
register emulation process, when needed.  However, in the migration
case (with VHE), the same handling is lacking.  So, enable it on the
first KVM_RUN with VHE (after the migration) when needed.

Fixes: d0c94c49792c ("KVM: arm64: Restore PMU configuration on first run")
Cc: stable@vger.kernel.org
Signed-off-by: Reiji Watanabe <reijiw@google.com>
---
 arch/arm64/kvm/pmu-emul.c | 1 +
 arch/arm64/kvm/sys_regs.c | 1 -
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index c243b10f3e15..5eca0cdd961d 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -558,6 +558,7 @@ void kvm_pmu_handle_pmcr(struct kvm_vcpu *vcpu, u64 val)
 		for_each_set_bit(i, &mask, 32)
 			kvm_pmu_set_pmc_value(kvm_vcpu_idx_to_pmc(vcpu, i), 0, true);
 	}
+	kvm_vcpu_pmu_restore_guest(vcpu);
 }
 
 static bool kvm_pmu_counter_is_enabled(struct kvm_pmc *pmc)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 1b2c161120be..34688918c811 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -794,7 +794,6 @@ static bool access_pmcr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
 		if (!kvm_supports_32bit_el0())
 			val |= ARMV8_PMU_PMCR_LC;
 		kvm_pmu_handle_pmcr(vcpu, val);
-		kvm_vcpu_pmu_restore_guest(vcpu);
 	} else {
 		/* PMCR.P & PMCR.C are RAZ */
 		val = __vcpu_sys_reg(vcpu, PMCR_EL0)
-- 
2.40.0.348.gf938b09366-goog


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