linux-kernel - [PATCH] KVM/x86: pmu: Fix #GP condition check for RDPMC emulation

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Message-Id: <20200708074409.39028-1-like.xu@linux.intel.com>
Date:   Wed,  8 Jul 2020 15:44:09 +0800
From:   Like Xu <like.xu@...ux.intel.com>
To:     Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Joerg Roedel <joro@...tes.org>, linux-kernel@...r.kernel.org,
        Like Xu <like.xu@...ux.intel.com>
Subject: [PATCH] KVM/x86: pmu: Fix #GP condition check for RDPMC emulation

In guest protected mode, if the current privilege level
is not 0 and the PCE flag in the CR4 register is cleared,
we will inject a #GP for RDPMC usage.

Signed-off-by: Like Xu <like.xu@...ux.intel.com>
---
 arch/x86/kvm/pmu.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index b86346903f2e..d080d475c808 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -372,6 +372,11 @@ int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
 	if (!pmc)
 		return 1;
 
+	if ((kvm_x86_ops.get_cpl(vcpu) != 0) &&
+	    !(kvm_read_cr4(vcpu) & X86_CR4_PCE) &&
+	    (kvm_read_cr4(vcpu) & X86_CR0_PE))
+		return 1;
+
 	*data = pmc_read_counter(pmc) & mask;
 	return 0;
 }
-- 
2.21.3