From: Nadav Amit <namit@cs.technion.ac.il>
Date: Thu, 18 Sep 2014 19:39:45 +0000 (+0300)
Subject: KVM: x86: Sysexit emulation does not mask RIP/RSP
X-Git-Tag: v3.12.38~22
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=23b4103455d52e2ffdc4758aea29ba6d70d246ca;p=thirdparty%2Fkernel%2Fstable.git

KVM: x86: Sysexit emulation does not mask RIP/RSP

commit bf0b682c9b6a6d6d54adf439bfe953feef7be2e8 upstream.

If the operand size is not 64-bit, then the sysexit instruction should assign
ECX to RSP and EDX to RIP.  The current code assigns the full 64-bits.

Fix it by masking.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index d28104924255d..8ab43ac68f067 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2372,6 +2372,8 @@ static int em_sysexit(struct x86_emulate_ctxt *ctxt)
 		if ((msr_data & 0xfffc) == 0x0)
 			return emulate_gp(ctxt, 0);
 		ss_sel = (u16)(msr_data + 24);
+		rcx = (u32)rcx;
+		rdx = (u32)rdx;
 		break;
 	case X86EMUL_MODE_PROT64:
 		cs_sel = (u16)(msr_data + 32);