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From: Nadav Amit <namit@cs.technion.ac.il>
To: pbonzini@redhat.com
Cc: gleb@kernel.org, tglx@linutronix.de, mingo@redhat.com,
	hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, Nadav Amit <namit@cs.technion.ac.il>
Subject: [PATCH v2 3/9] KVM: x86: Inter privilage level ret emulation is not implemeneted
Date: Wed, 18 Jun 2014 17:19:20 +0300	[thread overview]
Message-ID: <1403101166-23616-4-git-send-email-namit@cs.technion.ac.il> (raw)
In-Reply-To: <1403101166-23616-1-git-send-email-namit@cs.technion.ac.il>

Return unhandlable error on inter-privilage level ret instruction.  This is
since the current emulation does not check the privilage level correctly when
loading the CS, and does not pop RSP/SS as needed.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
---
 arch/x86/kvm/emulate.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 3c8d867..0183350 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2019,6 +2019,7 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt)
 {
 	int rc;
 	unsigned long cs;
+	int cpl = ctxt->ops->cpl(ctxt);
 
 	rc = emulate_pop(ctxt, &ctxt->_eip, ctxt->op_bytes);
 	if (rc != X86EMUL_CONTINUE)
@@ -2028,6 +2029,9 @@ static int em_ret_far(struct x86_emulate_ctxt *ctxt)
 	rc = emulate_pop(ctxt, &cs, ctxt->op_bytes);
 	if (rc != X86EMUL_CONTINUE)
 		return rc;
+	/* Outer-privilage level return is not implemented */
+	if (ctxt->mode >= X86EMUL_MODE_PROT16 && (cs & 3) > cpl)
+		return X86EMUL_UNHANDLEABLE;
 	rc = load_segment_descriptor(ctxt, (u16)cs, VCPU_SREG_CS);
 	return rc;
 }
-- 
1.9.1


  parent reply	other threads:[~2014-06-18 14:19 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-15 13:12 [PATCH 0/6] KVM: x86: More emulator bugs Nadav Amit
2014-06-15 13:12 ` [PATCH 1/6] KVM: x86: bit-ops emulation ignores offset on 64-bit Nadav Amit
2014-06-15 13:12 ` [PATCH 2/6] KVM: x86: Wrong emulation on 'xadd X, X' Nadav Amit
2014-06-16 17:38   ` Bandan Das
2014-06-17  5:16     ` Paolo Bonzini
2014-06-17 15:35       ` Bandan Das
2014-06-17 16:49         ` Paolo Bonzini
2014-06-15 13:12 ` [PATCH 3/6] KVM: x86: Inter privilage level ret emulation is not implemeneted Nadav Amit
2014-06-15 13:13 ` [PATCH 4/6] KVM: x86: emulation of dword cmov on long-mode should clear [63:32] Nadav Amit
2014-06-15 13:13 ` [PATCH 5/6] KVM: x86: NOP emulation clears (incorrectly) the high 32-bits of RAX Nadav Amit
2014-06-15 13:13 ` [PATCH 6/6] KVM: x86: check DR6/7 high-bits are clear only on long-mode Nadav Amit
2014-06-16 10:17   ` Paolo Bonzini
2014-06-16 10:33     ` Nadav Amit
2014-06-16 11:09       ` Paolo Bonzini
2014-06-16 11:53         ` Nadav Amit
2014-06-16 14:56           ` Paolo Bonzini
2014-06-16 17:07             ` Nadav Amit
2014-06-18 14:19             ` [PATCH v2 0/9] KVM: x86: More emulator bugs Nadav Amit
2014-06-18 14:19               ` [PATCH v2 1/9] KVM: x86: bit-ops emulation ignores offset on 64-bit Nadav Amit
2014-06-18 14:19               ` [PATCH v2 2/9] KVM: x86: Wrong emulation on 'xadd X, X' Nadav Amit
2014-06-18 14:19               ` Nadav Amit [this message]
2014-06-18 14:19               ` [PATCH v2 4/9] KVM: x86: emulation of dword cmov on long-mode should clear [63:32] Nadav Amit
2014-06-18 14:19               ` [PATCH v2 5/9] KVM: x86: NOP emulation clears (incorrectly) the high 32-bits of RAX Nadav Amit
2014-06-18 14:19               ` [PATCH v2 6/9] KVM: x86: check DR6/7 high-bits are clear only on long-mode Nadav Amit
2014-06-18 14:19               ` [PATCH v2 7/9] KVM: x86: Hypercall handling does not considers opsize correctly Nadav Amit
2014-06-18 14:19               ` [PATCH v2 8/9] KVM: vmx: handle_cr ignores 32/64-bit mode Nadav Amit
2014-06-18 14:19               ` [PATCH v2 9/9] KVM: vmx: vmx instructions handling does not consider cs.l Nadav Amit
2014-06-18 15:41                 ` Paolo Bonzini
2014-06-18 16:01                   ` Nadav Amit
2014-06-18 16:06                     ` Paolo Bonzini
2014-06-18 17:51                       ` Nadav Amit
2014-06-19  9:45                         ` Paolo Bonzini
2014-06-18 15:45               ` [PATCH v2 0/9] KVM: x86: More emulator bugs Paolo Bonzini
2014-06-16 10:18 ` [PATCH 0/6] " Paolo Bonzini

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