[PATCH] KVM: X86: convert bsf/bsr instructions toemulate_2op_SrcV_nobyte()

[Joerg Roedel]

The instruction emulation for bsrw is broken in KVM because
the code always uses bsr with 32 or 64 bit operand size for
emulation. Fix that by using emulate_2op_SrcV_nobyte() macro
to use guest operand size for emulation.

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
 arch/x86/kvm/emulate.c |   26 ++------------------------
 1 file changed, 2 insertions(+), 24 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 0d151e2..a6f8488 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3134,35 +3134,13 @@ static int em_btc(struct x86_emulate_ctxt *ctxt)
 
 static int em_bsf(struct x86_emulate_ctxt *ctxt)
 {
-	u8 zf;
-
-	__asm__ ("bsf %2, %0; setz %1"
-		 : "=r"(ctxt->dst.val), "=q"(zf)
-		 : "r"(ctxt->src.val));
-
-	ctxt->eflags &= ~X86_EFLAGS_ZF;
-	if (zf) {
-		ctxt->eflags |= X86_EFLAGS_ZF;
-		/* Disable writeback. */
-		ctxt->dst.type = OP_NONE;
-	}
+	emulate_2op_SrcV_nobyte(ctxt, "bsf");
 	return X86EMUL_CONTINUE;
 }
 
 static int em_bsr(struct x86_emulate_ctxt *ctxt)
 {
-	u8 zf;
-
-	__asm__ ("bsr %2, %0; setz %1"
-		 : "=r"(ctxt->dst.val), "=q"(zf)
-		 : "r"(ctxt->src.val));
-
-	ctxt->eflags &= ~X86_EFLAGS_ZF;
-	if (zf) {
-		ctxt->eflags |= X86_EFLAGS_ZF;
-		/* Disable writeback. */
-		ctxt->dst.type = OP_NONE;
-	}
+	emulate_2op_SrcV_nobyte(ctxt, "bsr");
 	return X86EMUL_CONTINUE;
 }
 
-- 
1.7.9.5


-- 
AMD Operating System Research Center

Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632

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