linux-kernel - [PATCH] KVM: SVM: Fix CPL export via SS.DPL

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Message-ID: <53B02CEB.7010607@web.de>
Date:	Sun, 29 Jun 2014 17:12:43 +0200
From:	Jan Kiszka <jan.kiszka@....de>
To:	Paolo Bonzini <pbonzini@...hat.com>
CC:	Gleb Natapov <gleb@...nel.org>, Borislav Petkov <bp@...en8.de>,
	lkml <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Steven Rostedt <rostedt@...dmis.org>, x86-ml <x86@...nel.org>,
	kvm@...r.kernel.org,
	Jörg Rödel 
	<joro@...tes.org>
Subject: [PATCH] KVM: SVM: Fix CPL export via SS.DPL

From: Jan Kiszka <jan.kiszka@...mens.com>

We import the CPL via SS.DPL since ae9fedc793. However, we fail to
export it this way so far. This caused spurious guest crashes, e.g. of
Linux when accessing the vmport from guest user space which triggered
register saving/restoring to/from host user space.

Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
---

Just in time for the next match :D

 arch/x86/kvm/svm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index ec8366c..b5e994a 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1462,6 +1462,7 @@ static void svm_get_segment(struct kvm_vcpu *vcpu,
 		 */
 		if (var->unusable)
 			var->db = 0;
+		var->dpl = to_svm(vcpu)->vmcb->save.cpl;
 		break;
 	}
 }
-- 
1.8.4.5


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