Received-SPF: softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Maxim Levitsky <mlevitsk@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Paolo Bonzini <pbonzini@redhat.com>
Subject: [PATCH 5.18 22/67] KVM: x86: fix typo in __try_cmpxchg_user causing non-atomicness
Date:   Fri,  3 Jun 2022 19:43:23 +0200
Message-Id: <20220603173821.365331799@linuxfoundation.org>
In-Reply-To: <20220603173820.731531504@linuxfoundation.org>
References: <20220603173820.731531504@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Maxim Levitsky <mlevitsk@redhat.com>

commit 33fbe6befa622c082f7d417896832856814bdde0 upstream.

This shows up as a TDP MMU leak when running nested.  Non-working cmpxchg on L0
relies makes L1 install two different shadow pages under same spte, and one of
them is leaked.

Fixes: 1c2361f667f36 ("KVM: x86: Use __try_cmpxchg_user() to emulate atomic accesses")
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220512101420.306759-1-mlevitsk@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/kvm/x86.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7268,7 +7268,7 @@ static int emulator_cmpxchg_emulated(str
 		goto emul_write;
 
 	hva = kvm_vcpu_gfn_to_hva(vcpu, gpa_to_gfn(gpa));
-	if (kvm_is_error_hva(addr))
+	if (kvm_is_error_hva(hva))
 		goto emul_write;
 
 	hva += offset_in_page(gpa);