linux-kernel - [PATCH 18/19] KVM: x86 emulator: emulate clflush

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1216123958-10717-19-git-send-email-avi@qumranet.com>
Date:	Tue, 15 Jul 2008 15:12:37 +0300
From:	Avi Kivity <avi@...ranet.com>
To:	kvm@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, Glauber Costa <gcosta@...hat.com>
Subject: [PATCH 18/19] KVM: x86 emulator: emulate clflush

From: Glauber Costa <gcosta@...hat.com>

If the guest issues a clflush in a mmio address, the instruction
can trap into the hypervisor. Currently, we do not decode clflush
properly, causing the guest to hang. This patch fixes this emulating
clflush (opcode 0f ae).

Signed-off-by: Glauber Costa <gcosta@...hat.com>
Signed-off-by: Avi Kivity <avi@...ranet.com>
---
 arch/x86/kvm/x86_emulate.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index 8bc63f6..f2f9046 100644
--- a/arch/x86/kvm/x86_emulate.c
+++ b/arch/x86/kvm/x86_emulate.c
@@ -219,7 +219,7 @@ static u16 twobyte_table[256] = {
 	/* 0xA0 - 0xA7 */
 	0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0,
 	/* 0xA8 - 0xAF */
-	0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0,
+	0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, ModRM, 0,
 	/* 0xB0 - 0xB7 */
 	ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, 0,
 	    DstMem | SrcReg | ModRM | BitOp,
@@ -1947,6 +1947,8 @@ twobyte_insn:
 		c->src.val &= (c->dst.bytes << 3) - 1;
 		emulate_2op_SrcV_nobyte("bts", c->src, c->dst, ctxt->eflags);
 		break;
+	case 0xae:              /* clflush */
+		break;
 	case 0xb0 ... 0xb1:	/* cmpxchg */
 		/*
 		 * Save real source value, then compare EAX against
-- 
1.5.6.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/