linux-kernel - [PATCH v4 05/12] KVM: x86/pmu: Error when user sets the GLOBAL

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Message-Id: <20230214050757.9623-6-likexu@tencent.com>
Date:   Tue, 14 Feb 2023 13:07:50 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4 05/12] KVM: x86/pmu: Error when user sets the GLOBAL_STATUS reserved bits

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

If the user space sets reserved bits when restoring the MSR_CORE_
PERF_GLOBAL_STATUS register, these bits will be accidentally returned
when the guest runs a read access to this register, and cannot be cleared
up inside the guest, which makes the guest's PMI handler very confused.

Signed-off-by: Like Xu <likexu@...cent.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 904f832fc55d..aaea25d2cae8 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -397,7 +397,7 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 			reprogram_fixed_counters(pmu, data);
 		break;
 	case MSR_CORE_PERF_GLOBAL_STATUS:
-		if (!msr_info->host_initiated)
+		if (!msr_info->host_initiated || (data & pmu->global_ovf_ctrl_mask))
 			return 1; /* RO MSR */
 
 		pmu->global_status = data;
-- 
2.39.1