[PATCH] KVM: Emulate multibyte NOP

From: Paolo Bonzini
Date: Thu May 30 2013 - 07:22:58 EST


This is encountered when booting RHEL5.9 64-bit. There is another bug
after this one that is not a simple emulation failure, but this one lets
the boot proceed a bit.

Cc: <stable@xxxxxxxxxxxxxxx> # 3.9
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 48e6abd..aa68106 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3987,7 +3987,8 @@ static const struct opcode twobyte_table[256] = {
DI(ImplicitOps | Priv, invd), DI(ImplicitOps | Priv, wbinvd), N, N,
N, D(ImplicitOps | ModRM), N, N,
/* 0x10 - 0x1F */
- N, N, N, N, N, N, N, N, D(ImplicitOps | ModRM), N, N, N, N, N, N, N,
+ N, N, N, N, N, N, N, N,
+ D(ImplicitOps | ModRM), N, N, N, N, N, N, D(ImplicitOps | ModRM),
/* 0x20 - 0x2F */
DIP(ModRM | DstMem | Priv | Op3264, cr_read, check_cr_read),
DIP(ModRM | DstMem | Priv | Op3264, dr_read, check_dr_read),
@@ -4822,6 +4823,7 @@ twobyte_insn:
case 0x08: /* invd */
case 0x0d: /* GrpP (prefetch) */
case 0x18: /* Grp16 (prefetch/nop) */
+ case 0x1f: /* nop */
break;
case 0x20: /* mov cr, reg */
ctxt->dst.val = ops->get_cr(ctxt, ctxt->modrm_reg);
--
1.8.1.4

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