Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Paolo Bonzini <pbonzini@redhat.com>
Subject: [PATCH 5.5 158/176] KVM: x86: Remove spurious kvm_mmu_unload() from vcpu destruction path
Date:   Tue,  3 Mar 2020 18:43:42 +0100
Message-Id: <20200303174322.678712535@linuxfoundation.org>
In-Reply-To: <20200303174304.593872177@linuxfoundation.org>
References: <20200303174304.593872177@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Sean Christopherson <sean.j.christopherson@intel.com>

commit 9d979c7e6ff43ca3200ffcb74f57415fd633a2da upstream.

x86 does not load its MMU until KVM_RUN, which cannot be invoked until
after vCPU creation succeeds.  Given that kvm_arch_vcpu_destroy() is
called if and only if vCPU creation fails, it is impossible for the MMU
to be loaded.

Note, the bogus kvm_mmu_unload() call was added during an unrelated
refactoring of vCPU allocation, i.e. was presumably added as an
opportunstic "fix" for a perceived leak.

Fixes: fb3f0f51d92d1 ("KVM: Dynamically allocate vcpus")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/kvm/x86.c |    4 ----
 1 file changed, 4 deletions(-)

--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9229,10 +9229,6 @@ void kvm_arch_vcpu_destroy(struct kvm_vc
 {
 	vcpu->arch.apf.msr_val = 0;
 
-	vcpu_load(vcpu);
-	kvm_mmu_unload(vcpu);
-	vcpu_put(vcpu);
-
 	kvm_arch_vcpu_free(vcpu);
 }